Canine Cardiology Quiz
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Canine Cardiology Quiz

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@LighterAmber

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Questions and Answers

Which clinical sign is indicative of right-sided heart failure?

  • Normal pulse quality
  • Cough (correct)
  • Weight loss
  • Exercise intolerance

    • What distinguishing physical examination finding might indicate tricuspid regurgitation?

  • Systolic left apical murmur
  • Normal to pale mucous membrane color
  • Jugular venous distension (correct)
  • Gallop rhythm

    • Which of the following is a common sign that may remain unnoticed in these dogs?

  • Arrhythmia
  • Ascites
  • Sudden death
  • Exercise intolerance (correct)

    • Which of the following breeds is commonly affected by fatty or fibro-fatty infiltration of the right ventricle?

    <p>Dachshund</p> Signup and view all the answers

    Which diagnostic method is most effective for assessing left atrial enlargement?

    <p>Echocardiogram</p> Signup and view all the answers

    Which symptom is NOT typically associated with lethargy in affected dogs?

    <p>Normal blood pressure</p> Signup and view all the answers

    Which of the following gastro-intestinal symptoms might coincide with heart failure in small breeds?

    <p>Vomiting</p> Signup and view all the answers

    What does a mid-systolic click typically indicate in canine cardiac assessments?

    <p>Mitral regurgitation</p> Signup and view all the answers

    What is the most common clinical sign observed in dogs with cardiac anomalies?

    <p>Exercise intolerance</p> Signup and view all the answers

    Which breed is NOT commonly associated with congenital heart disease?

    <p>Golden retriever</p> Signup and view all the answers

    Which diagnostic tool would best indicate left ventricular enlargement?

    <p>Echocardiogram</p> Signup and view all the answers

    What characteristic is associated with aortic regurgitation during physical examination?

    <p>Diastolic left basilar murmur</p> Signup and view all the answers

    Which of the following is true regarding prognosis after surgical ligation of the ligamentum arteriosum?

    <p>Residual esophageal damage may occur.</p> Signup and view all the answers

    What does the presence of tall R waves in lead II suggest during an electrocardiogram?

    <p>Left ventricular hypertrophy</p> Signup and view all the answers

    What is a common complication following myocardial disease in dogs?

    <p>Arrhythmias</p> Signup and view all the answers

    What underlying condition may contribute to the development of dilated cardiomyopathy in dogs?

    <p>Genetic predisposition</p> Signup and view all the answers

    What is the primary factor that leads to an increase in norepinephrine levels?

    <p>Decrease in cardiac output</p> Signup and view all the answers

    Which of the following conditions is characterized by dilated atrial or ventricular chambers?

    <p>Dilated cardiomyopathy</p> Signup and view all the answers

    What type of hypertrophy results from volume overload in the heart?

    <p>Eccentric hypertrophy</p> Signup and view all the answers

    Which diagnostic test is primarily used to evaluate the electrical activity of the heart?

    <p>Electrocardiography</p> Signup and view all the answers

    What does systemic vascular resistance primarily resist?

    <p>Blood flow through the systemic arterioles</p> Signup and view all the answers

    Which heart condition is associated with concentric hypertrophy?

    <p>Systemic hypertension</p> Signup and view all the answers

    Which diagnostic tool provides continuous monitoring of heart activity over an extended period?

    <p>Holter monitor</p> Signup and view all the answers

    Which condition is not typically involved in the establishment of eccentric hypertrophy?

    <p>Aortic stenosis</p> Signup and view all the answers

    Which of the following conditions is indicated by right ventricular enlargement?

    <p>Tricuspid regurgitation</p> Signup and view all the answers

    What is the most common valve affected in valvular endocarditis?

    <p>Aortic valve</p> Signup and view all the answers

    Which of the following signs indicates the presence of right heart enlargement?

    <p>Signs of pulmonary artery enlargement</p> Signup and view all the answers

    Which of the following is a potential cause of thickened valve leaflets?

    <p>Aortic stenosis</p> Signup and view all the answers

    What abnormal finding might be observed on an echocardiogram indicative of right atrial enlargement?

    <p>Pleural effusion</p> Signup and view all the answers

    Which organism is most commonly associated with valvular endocarditis?

    <p>Staphylococcus aureus</p> Signup and view all the answers

    Which of the following is a common consequence of tricuspid regurgitation?

    <p>Right atrial enlargement</p> Signup and view all the answers

    What does the presence of a wide P wave in lead II suggest?

    <p>Left atrial enlargement</p> Signup and view all the answers

    Which symptom is NOT typically associated with right-sided heart failure?

    <p>Palpitations</p> Signup and view all the answers

    What arrhythmia is commonly linked with elevated right ventricular pressures due to pulmonary hypertension?

    <p>Systolic right heart murmur of tricuspid regurgitation</p> Signup and view all the answers

    Which finding in electrocardiography suggests right atrial enlargement?

    <p>Tall P waves in lead II</p> Signup and view all the answers

    What condition can occur when heartworms migrate into the vena cava?

    <p>Caval syndrome</p> Signup and view all the answers

    What type of pulmonary pattern may indicate complications of heartworm disease?

    <p>Bronchointerstitial to alveolar pulmonary pattern</p> Signup and view all the answers

    Which laboratory finding is typically NOT associated with caval syndrome?

    <p>Leukopenia</p> Signup and view all the answers

    What physical examination finding suggests the presence of right ventricular enlargement in an ECG?

    <p>Deep S waves in leads I, II, III, and aVf</p> Signup and view all the answers

    Which sign is indicative of tricuspid regurgitation in heart disease?

    <p>Systolic murmur</p> Signup and view all the answers

    What is a treatment option that can be used for managing thromboembolism in patients?

    <p>Clopidogrel</p> Signup and view all the answers

    Which of the following is a characteristic finding in patients with moderate prognosis in cardiomyopathy?

    <p>May develop clinical signs</p> Signup and view all the answers

    Which option best describes chronic heart failure (CHF) in the context of medical management?

    <p>Often requires diuretics for fluid management</p> Signup and view all the answers

    What is a significant risk associated with valvular endocardiosis in small breed dogs?

    <p>Acute decompensation due to valve rupture</p> Signup and view all the answers

    Which of the following treatments is indicated for managing congestive heart failure?

    <p>Administering oxygen</p> Signup and view all the answers

    Which statement accurately reflects the prognosis for patients with severe heart conditions?

    <p>Severe cases typically yield a poor prognosis</p> Signup and view all the answers

    What is a common consequence of untreated arrhythmogenic right ventricular cardiomyopathy?

    <p>Sudden cardiac arrest due to arrhythmias</p> Signup and view all the answers

    Which of the following is a true statement regarding the commonality of heart diseases in cats?

    <p>Hypertrophic cardiomyopathy is less common in cats</p> Signup and view all the answers

    What physiological change is primarily associated with an increase in norepinephrine levels?

    <p>Decreased cardiac output</p> Signup and view all the answers

    Which type of hypertrophy is characterized by ventricular wall thickening due to a pressure overload?

    <p>Concentric hypertrophy</p> Signup and view all the answers

    Which heart condition is an example of eccentric hypertrophy?

    <p>Dilated cardiomyopathy</p> Signup and view all the answers

    Which diagnostic test is primarily used to assess the structure and function of the heart?

    <p>Echocardiography</p> Signup and view all the answers

    Which of the following conditions can lead to concentric hypertrophy due to pressure overload?

    <p>Aortic stenosis</p> Signup and view all the answers

    Which diagnostic test provides continuous monitoring of heart activity over an extended duration?

    <p>Holter monitor</p> Signup and view all the answers

    What does systemic vascular resistance primarily resist in the circulatory system?

    <p>Blood flow through the systemic arterioles</p> Signup and view all the answers

    What type of changes are typically observed in echocardiography indicative of eccentric hypertrophy?

    <p>Dilated chambers with normal wall thickness</p> Signup and view all the answers

    Which nutrient deficiency has been associated with hypertrophic cardiomyopathy in cats and is favorable with supplementation?

    <p>Taurine</p> Signup and view all the answers

    What type of hypertrophy is characterized by a dynamic obstruction to blood flow in the left ventricular outflow tract?

    <p>Hypertrophic obstructive cardiomyopathy</p> Signup and view all the answers

    Which breed is noted for having an autosomal dominant inheritance pattern in relation to hypertrophic cardiomyopathy?

    <p>Maine Coon</p> Signup and view all the answers

    What secondary cause can lead to ventricular hypertrophy in feline patients?

    <p>Systemic hypertension</p> Signup and view all the answers

    Which clinical sign is commonly associated with hypertrophic cardiomyopathy in Irish Wolfhounds?

    <p>Atrial fibrillation</p> Signup and view all the answers

    In which dog breed is X-linked muscular dystrophy associated with myocardial lesions before one year of age?

    <p>Great Dane</p> Signup and view all the answers

    Which of the following diseases would NOT be considered a secondary cause of ventricular hypertrophy in cats?

    <p>Bacterial infections</p> Signup and view all the answers

    Which breed variation of hypertrophic cardiomyopathy is linked to both taurine and L-carnitine deficiency?

    <p>Cocker Spaniel</p> Signup and view all the answers

    What is the primary benefit of using Melarsomine (Immiticide) over thiacetarsamide?

    <p>It is safer for the patient.</p> Signup and view all the answers

    What is the recommended protocol for administering Melarsomine (Immiticide)?

    <p>Two intramuscular injections 24 hours apart.</p> Signup and view all the answers

    Which of the following statements about the split protocol for heartworm treatment is true?

    <p>It is preferred when financial issues arise.</p> Signup and view all the answers

    What is the purpose of concurrent administration of anti-inflammatory corticosteroids during heartworm treatment?

    <p>To manage side effects of heartworm disease.</p> Signup and view all the answers

    How long should a dog be under cage confinement after receiving Melarsomine treatment?

    <p>4 weeks with the standard protocol.</p> Signup and view all the answers

    What is a key recommendation regarding aspirin therapy during heartworm treatment?

    <p>It is not recommended.</p> Signup and view all the answers

    What should be done 4 to 6 months following heartworm treatment?

    <p>A recheck heartworm antigen test is required.</p> Signup and view all the answers

    Which type of dogs might claim the benefit of split protocol treatment?

    <p>Dogs displaying no clinical signs.</p> Signup and view all the answers

    What is a likely consequence of a severe congenital lack of ductal smooth muscle?

    <p>Risk of sudden death</p> Signup and view all the answers

    Which diagnostic result is most indicative of right ventricular enlargement?

    <p>Deep S waves in electrocardiogram leads</p> Signup and view all the answers

    Which physical examination finding is consistent with a diagnosis of ASD?

    <p>Split second heart sound</p> Signup and view all the answers

    What clinical sign may be observed with a large defect associated with ASD?

    <p>Increased exercise intolerance</p> Signup and view all the answers

    Which breed is commonly associated with the development of ASD?

    <p>Shetland sheepdog</p> Signup and view all the answers

    What is a significant echocardiographic finding in the diagnosis of ASD?

    <p>Funnel-shaped narrowing at the pulmonary artery</p> Signup and view all the answers

    Which of the following clinical signs is typically absent in mild cases of congenital heart defects?

    <p>Clinical signs altogether</p> Signup and view all the answers

    Which group of symptoms may signify the presence of right-sided heart failure with large defects?

    <p>Ascites and jugular venous distension</p> Signup and view all the answers

    What is a common treatment option for managing congestive heart failure in dogs?

    <p>Diuretics</p> Signup and view all the answers

    Which diagnostic method can indicate left atrial enlargement?

    <p>Echocardiogram</p> Signup and view all the answers

    Which statement about ACE inhibitors in the treatment of heart disease is accurate?

    <p>They are commonly used to delay disease progression.</p> Signup and view all the answers

    What does left ventricular enlargement typically suggest in a patient?

    <p>Aortic stenosis</p> Signup and view all the answers

    Which symptom is associated with systemic hypertension in cardiac conditions?

    <p>Left ventricular hypertrophy</p> Signup and view all the answers

    What ECG finding may indicate left atrial enlargement?

    <p>Wide P waves in lead II</p> Signup and view all the answers

    In assessing aortic regurgitation, which echocardiographic finding is expected?

    <p>Thickened aortic valve leaflets</p> Signup and view all the answers

    What might elevated transaortic velocities on an echocardiogram indicate?

    <p>Aortic stenosis</p> Signup and view all the answers

    Which of the following statements about the prognosis of patent ductus arteriosus (PDA) is true?

    <p>Small PDA cases have a favorable prognosis and may not develop clinical signs.</p> Signup and view all the answers

    What is the primary outcome of untreated right-to-left shunting PDA?

    <p>Severe hypoxemia and death.</p> Signup and view all the answers

    Which diagnostic method is most useful for assessing structural heart conditions associated with pulmonic stenosis?

    <p>Echocardiogram.</p> Signup and view all the answers

    What clinical sign is commonly associated with significant pulmonic valvular regurgitation?

    <p>Diastolic left basilar murmur.</p> Signup and view all the answers

    In managing polycythemia attributed to hypoxemia, what treatment is often considered?

    <p>Phlebotomy or hydroxyurea.</p> Signup and view all the answers

    What finding might be observed on an electrocardiogram indicative of right ventricular hypertrophy?

    <p>Tall R waves in lead V1.</p> Signup and view all the answers

    Which echocardiographic finding best suggests the presence of poststenotic dilation of the main pulmonary artery?

    <p>Interventricular septal flattening.</p> Signup and view all the answers

    Which complication is a concern when considering closure of a right-to-left shunting PDA?

    <p>Severe hypoxemia.</p> Signup and view all the answers

    What method is used to detect heartworm antigens specifically in female worms?

    <p>ELISA tests</p> Signup and view all the answers

    What could explain the absence of microfilaria in a dog despite a heartworm infection?

    <p>All-female infection</p> Signup and view all the answers

    What is a common laboratory finding associated with heartworm disease?

    <p>Eosinophilia</p> Signup and view all the answers

    In heartworm disease, what radiographic change is likely to be observed?

    <p>Enlarged main pulmonary artery</p> Signup and view all the answers

    What treatment method is considered for managing the presence of microfilaria?

    <p>Microfilaricidal treatment</p> Signup and view all the answers

    Which laboratory finding in the biochemistry panel could indicate heartworm infection?

    <p>Elevated serum alkaline phosphatase</p> Signup and view all the answers

    What important consideration should be taken before administering treatment for microfilaria?

    <p>Use of corticosteroids prior to treatment</p> Signup and view all the answers

    Which of the following is a limitation of the heartworm antibody test when used in dogs?

    <p>Nonspecific and not widely used</p> Signup and view all the answers

    What diagnostic imaging finding is commonly associated with severe pulmonic stenosis in dogs?

    <p>Rounding of the sternal border</p> Signup and view all the answers

    Which clinical sign is most typically observed in dogs with right ventricular enlargement?

    <p>Deep S waves in leads I and III</p> Signup and view all the answers

    What anatomical abnormality could possibly cause pulmonic stenosis in dogs?

    <p>Anomalous left coronary artery</p> Signup and view all the answers

    What is a typical treatment option for managing valvular pulmonic stenosis in dogs?

    <p>Balloon valvuloplasty</p> Signup and view all the answers

    Which breed is most commonly affected by congenital pulmonic stenosis?

    <p>English Bulldog</p> Signup and view all the answers

    What finding in a thoracic radiograph might indicate the presence of right atrial enlargement?

    <p>Enlarged caudal vena cava</p> Signup and view all the answers

    What characteristic appears on an electrocardiogram for dogs with significant right ventricular overload?

    <p>Right axis deviation</p> Signup and view all the answers

    What is a typical change in the pulmonary artery observed on thoracic radiographs due to pulmonic stenosis?

    <p>Poststenotic dilation</p> Signup and view all the answers

    Which breed is primarily noted for presenting with arrhythmias related to hypertrophic cardiomyopathy?

    <p>Boxer</p> Signup and view all the answers

    What is a significant consequence of hypertrophic obstructive cardiomyopathy (HOCM) in cats?

    <p>Dynamic obstruction to the left ventricular outflow tract</p> Signup and view all the answers

    What inheritance pattern is associated with hypertrophic cardiomyopathy in Maine coon cats?

    <p>Autosomal dominant</p> Signup and view all the answers

    Which of the following conditions is NOT considered a secondary cause of ventricular hypertrophy?

    <p>Hypothyroidism</p> Signup and view all the answers

    Which cat breed is commonly associated with both taurine and L-carnitine deficiencies impacting hypertrophic cardiomyopathy?

    <p>Cocker spaniel</p> Signup and view all the answers

    A trial of taurine supplementation is likely to be effective in reversing hypertrophic cardiomyopathy in which specific condition?

    <p>Taurine deficiency</p> Signup and view all the answers

    Which of the following is a common clinical manifestation in cats with hypertrophic cardiomyopathy?

    <p>Exercise intolerance</p> Signup and view all the answers

    What primary issue leads to myocardial lesions at a young age in certain breeds like the golden retriever?

    <p>Genetic mutations</p> Signup and view all the answers

    What is the primary function of the heartworm antigen test in dogs?

    <p>Identifies antigen from gravid female heartworms</p> Signup and view all the answers

    What is a notable limitation of the heartworm antigen test in cats?

    <p>Less than 50% of heartworm-positive cats test positive</p> Signup and view all the answers

    Which microfilaria test is mentioned as a method for detecting circulating microfilaria in dogs and cats?

    <p>Modified Knott test</p> Signup and view all the answers

    What is one potential finding from thoracic radiographs in a dog suspected of heartworm disease?

    <p>Normal appearance without any abnormalities</p> Signup and view all the answers

    What is the characteristic effect of milbemycin in the context of heartworm treatment?

    <p>Gradually kills microfilaria</p> Signup and view all the answers

    What is the most likely diagnostic approach to evaluate congenital heart disease in dogs?

    <p>Echocardiogram</p> Signup and view all the answers

    Which of the following clinical signs may not be immediately apparent in patients with heart disease?

    <p>Lethargy</p> Signup and view all the answers

    Which of these options is NOT typically found during a physical examination of a dog with aortic regurgitation?

    <p>Systolic right sternal murmur</p> Signup and view all the answers

    What is the primary treatment for a patent ductus arteriosus in dogs?

    <p>Surgical ligation of the ligamentum arteriosum</p> Signup and view all the answers

    Which breed of dogs is particularly noted for potential heritable dilated cardiomyopathy?

    <p>Boxer</p> Signup and view all the answers

    What characteristic on an electrocardiogram suggests left atrial enlargement?

    <p>Wide P waves in lead II</p> Signup and view all the answers

    Which clinical sign is most commonly associated with left ventricular enlargement in dogs?

    <p>Exertional dyspnea</p> Signup and view all the answers

    In dogs, which condition is characterized by the prominence of small ventricular septal defects?

    <p>Acquired heart disease</p> Signup and view all the answers

    Which of the following indicators might still appear normal in a cat with early-stage cardiomegaly?

    <p>Thoracic radiographs</p> Signup and view all the answers

    What type of therapy is used in the medical management of congestive heart failure (CHF)?

    <p>Diuretics</p> Signup and view all the answers

    In the context of heart diseases in cats, which condition is characterized by left and/or right atrial enlargement?

    <p>Generalized cardiomegaly</p> Signup and view all the answers

    Which statement about the prognosis for cats receiving taurine supplementation is true?

    <p>Prognosis is favorable with taurine supplementation</p> Signup and view all the answers

    Which specific treatment might be necessary in the case of pleural effusion during CHF management?

    <p>Pleurocentesis</p> Signup and view all the answers

    What is a typical characteristic observed on thoracic radiographs that can indicate severe heart disease in cats?

    <p>Left atrial dilation</p> Signup and view all the answers

    What complication may arise from untreated thromboembolism in cats?

    <p>Pulmonary edema</p> Signup and view all the answers

    Which treatment is recommended for managing arrhythmias in cats diagnosed with cardiomyopathy?

    <p>Antiarrhythmic therapy</p> Signup and view all the answers

    What is the primary purpose of a heartworm antigen test?

    <p>Identifies the presence of female heartworm antigens</p> Signup and view all the answers

    Which of the following is a reason for the absence of microfilaria in a test result?

    <p>An all-female infection</p> Signup and view all the answers

    What common finding might be observed in thoracic radiographs of a dog with advanced heartworm disease?

    <p>Enlarged main pulmonary artery</p> Signup and view all the answers

    When interpreting a biochemical panel for a dog suspected of having heartworm disease, which of the following findings could indicate liver involvement?

    <p>Elevated serum alanine transferase</p> Signup and view all the answers

    Which treatment option is typically employed for microfilaricidal action in heartworm-infected dogs?

    <p>Preventative doses of ivermectin or milbemycin oxime</p> Signup and view all the answers

    Which laboratory finding is often associated with heartworm disease in dogs?

    <p>Thrombocytopenia</p> Signup and view all the answers

    What is a notable disadvantage of using heartworm antibody tests in dogs?

    <p>They are no longer in use</p> Signup and view all the answers

    Which of the following symptoms might be present in a clinic evaluation of a dog suspected of heartworm disease?

    <p>Eosinophilia</p> Signup and view all the answers

    What is a potential clinical sign that may indicate the presence of left-sided heart failure?

    <p>Gallop rhythm</p> Signup and view all the answers

    Which diagnostic method is primarily useful for assessing pulmonary congestion related to heart failure?

    <p>Echocardiography</p> Signup and view all the answers

    Which of the following options accurately describes a consequence associated with untreated congestive heart failure (CHF)?

    <p>Development of arrhythmias</p> Signup and view all the answers

    What physical examination finding is indicative of right heart involvement in heart disease?

    <p>Fluid accumulation in the abdominal cavity</p> Signup and view all the answers

    Which of the following factors is NOT typically monitored during the medical management of cardiac patients?

    <p>Systolic blood pressure</p> Signup and view all the answers

    What characteristic in the physical examination may suggest significant heart dysfunction?

    <p>Irregular rhythms</p> Signup and view all the answers

    In evaluating for right ventricular enlargement, which clinical sign would be the most relevant?

    <p>Right atrial enlargement</p> Signup and view all the answers

    Which treatment option is currently under investigation for its effectiveness in managing heart conditions?

    <p>Beta-blockers</p> Signup and view all the answers

    What is the prognosis for patients with severe diastolic dysfunction?

    <p>Poor, with developed clinical signs</p> Signup and view all the answers

    Which of the following diagnostic tools may show generalized cardiomegaly associated with advanced heart disease?

    <p>Thoracic radiographs</p> Signup and view all the answers

    Which clinical signs are most similar to hypertrophic cardiomyopathy?

    <p>Diastolic dysfunction and rapid heart rate</p> Signup and view all the answers

    What condition might be indicated by the presence of pleural effusion in a feline patient?

    <p>Left-sided congestive heart failure</p> Signup and view all the answers

    Which of the following findings is commonly associated with early stages of heart disease in cats?

    <p>Normal electrocardiography results</p> Signup and view all the answers

    What is a common diagnostic finding in cases of myocarditis?

    <p>Marked biatrial enlargement</p> Signup and view all the answers

    What might an echocardiogram reveal in a feline patient with heart failure?

    <p>Mitral valve abnormalities</p> Signup and view all the answers

    Which of the following elements does NOT contribute to the severity of diastolic dysfunction?

    <p>Patient's age</p> Signup and view all the answers

    Which complication is primarily associated with hypoxemia in Tetralogy of Fallot?

    <p>Polycythemia</p> Signup and view all the answers

    What is the role of the Blalock Taussig shunt in the management of Tetralogy of Fallot?

    <p>To create a communication between systemic and pulmonary circulation</p> Signup and view all the answers

    Which of the following breeds is notably associated with Tetralogy of Fallot?

    <p>Keeshond</p> Signup and view all the answers

    What is a significant clinical sign observed during a physical examination of a dog with Tetralogy of Fallot?

    <p>Cyanosis with exercise</p> Signup and view all the answers

    Which type of heart defect is primarily identified in Tetralogy of Fallot?

    <p>Pulmonary stenosis</p> Signup and view all the answers

    What management strategy is crucial for maintaining packed cell volume (PCV) in a patient with Tetralogy of Fallot?

    <p>Phlebotomy to reduce red blood cells</p> Signup and view all the answers

    Which of the following is a proposed medical treatment to manage polycythemia in affected dogs?

    <p>Hydroxyurea</p> Signup and view all the answers

    What characteristic finding might you expect during auscultation of a dog with Tetralogy of Fallot?

    <p>Systolic murmur</p> Signup and view all the answers

    What is a potential risk associated with prolonged monthly use of Ivermectin in dogs?

    <p>Right ventricular enlargement</p> Signup and view all the answers

    Which laboratory finding is commonly associated with microfilaremic dogs after receiving diethylcarbamazine?

    <p>Eosinophilia</p> Signup and view all the answers

    When considering prognosis for heartworm disease, which of the following scenarios is deemed most severe?

    <p>Severe disease with clinical signs present</p> Signup and view all the answers

    Which echocardiogram finding is particularly sensitive for detecting heartworms in feline patients?

    <p>Increased right ventricular wall thickness</p> Signup and view all the answers

    Which of the following treatments is administered daily for effective heartworm prevention?

    <p>Ivermectin</p> Signup and view all the answers

    What could potentially happen to microfilaria-positive cats undergoing treatment?

    <p>Significant risk of severe side effects</p> Signup and view all the answers

    In cases of caval syndrome, which finding most accurately reflects the advanced state of heartworm disease?

    <p>Presence of heartworms in the right atrium</p> Signup and view all the answers

    What is the expected prepatent period for heartworms in cats?

    <p>8 months</p> Signup and view all the answers

    What type of management is commonly indicated for severe or symptomatic valvular pulmonic stenosis?

    <p>Balloon valvuloplasty</p> Signup and view all the answers

    Which of the following is the most significant risk factor for a shortened lifespan due to pulmonic stenosis?

    <p>High peak transpulmonic velocities</p> Signup and view all the answers

    What finding on electrocardiography suggests right ventricular enlargement?

    <p>Deep S waves in leads I, II, III, aVf</p> Signup and view all the answers

    In cases of pulmonic stenosis, which surgical option is characterized by especially high difficulty?

    <p>Resection of the stenotic area</p> Signup and view all the answers

    Which condition is most likely to result from untreated moderate to severe pulmonic stenosis?

    <p>Sudden death</p> Signup and view all the answers

    What is a significant change observed in electrocardiography specifically indicative of right atrial enlargement?

    <p>Tall P waves in lead II</p> Signup and view all the answers

    What medical management is part of the treatment protocol for congestive right-sided heart failure?

    <p>Increased oxygen supply</p> Signup and view all the answers

    What anatomical or functional abnormality is introduced by a conduit bypassing a stenosis?

    <p>Restricted motion of pulmonic valve leaflets</p> Signup and view all the answers

    What is a common outcome of constrictive pericardial disease in cats?

    <p>Syncope and sudden death</p> Signup and view all the answers

    Which diagnostic tool is preferable to perform prior to pericardiocentesis if the patient is stable?

    <p>Echocardiogram</p> Signup and view all the answers

    What is the primary characteristic of pericardial effusion in cats?

    <p>Impaired ventricular filling</p> Signup and view all the answers

    Which of the following is NOT a clinical sign associated with pericardial effusion?

    <p>Palpitations</p> Signup and view all the answers

    What is the treatment approach for symptomatic patients with constrictive pericardial disease?

    <p>Surgical repair of the pericardium</p> Signup and view all the answers

    Which type of fluid is typically found in pericardial effusion?

    <p>Transudate</p> Signup and view all the answers

    What can complicate the surgical repair of constrictive pericardial disease?

    <p>Pericardial adhesions</p> Signup and view all the answers

    In which demographic is pericardial effusion more commonly observed?

    <p>Middle-aged to older, large-breed dogs</p> Signup and view all the answers

    What is the primary clinical presentation associated with a vascular ring anomaly?

    <p>Esophageal obstruction leading to regurgitation</p> Signup and view all the answers

    In the context of Trypanosoma cruzi infection, which of the following describes its life cycle stages?

    <p>The trypomastigote stage is responsible for transmission</p> Signup and view all the answers

    Which of the following clinical signs in dogs may indicate a heart condition related to Toxoplasma gondii?

    <p>Hepatosplenomegaly</p> Signup and view all the answers

    What is the expected outcome for puppies affected by Parvovirus in the historical context of the 1970s and 1980s?

    <p>Shortened life span without any defects</p> Signup and view all the answers

    Which statement accurately reflects the treatment approach for conditions caused by Toxoplasma gondii?

    <p>Symptomatic treatment is the primary strategy</p> Signup and view all the answers

    What describes the primary role of afterload in the cardiovascular system?

    <p>The force opposing ventricular contraction</p> Signup and view all the answers

    Which of the following best characterizes positive inotropy?

    <p>Increased myocardial contractility</p> Signup and view all the answers

    What does negative chronotropy signify?

    <p>A decrease in heart rate</p> Signup and view all the answers

    What can result from left-sided heart failure?

    <p>Pulmonary edema</p> Signup and view all the answers

    Which consequence is associated with forward heart failure?

    <p>Decreased cardiac output</p> Signup and view all the answers

    Which physiological change is primarily driven by the activation of the renin angiotensin aldosterone system (RAAS)?

    <p>Increased sodium chloride retention</p> Signup and view all the answers

    What condition is indicated by right-sided heart failure?

    <p>Hepatomegaly and ascites</p> Signup and view all the answers

    What is the term for the relaxation phase of the heart chambers?

    <p>Diastole</p> Signup and view all the answers

    What factor is commonly associated with the prognosis of a patient diagnosed with an esophageal condition due to congenital heart disease?

    <p>Residual esophageal functional and structural damage</p> Signup and view all the answers

    Which diagnostic method provides a comprehensive view of left ventricular enlargement and potential structural defects?

    <p>Echocardiogram</p> Signup and view all the answers

    Which clinical sign might suggest a need for further investigation in a patient with suspected myocardial disease?

    <p>Diastolic left basilar murmur</p> Signup and view all the answers

    What finding on an electrocardiogram might indicate a potential issue with left atrial enlargement?

    <p>Wide P waves in lead II</p> Signup and view all the answers

    Which breed is more commonly affected by dilated cardiomyopathy due to genetic predisposition?

    <p>Great Dane</p> Signup and view all the answers

    In dogs, which echocardiographic finding may indicate the presence of a ventricular septal defect?

    <p>Left atrial enlargement</p> Signup and view all the answers

    What is the primary treatment approach for managing a significant ductus arteriosus in a patient?

    <p>Surgical ligation of the ligamentum arteriosum</p> Signup and view all the answers

    What is a common consequence of aortic valve leaflet prolapse in an echocardiographic assessment?

    <p>Diastolic left basilar murmur</p> Signup and view all the answers

    What is a potential complication of congenital heart defects in dogs?

    <p>Ventricular systolic dysfunction</p> Signup and view all the answers

    Which breed is least likely to be affected by congenital heart disease?

    <p>Beagle</p> Signup and view all the answers

    What is a notable challenge associated with performing patch graft surgery for heart defects?

    <p>Requires specialized equipment</p> Signup and view all the answers

    What is an acute physiological response of the heart to a persistently fast heart rate?

    <p>Myocardial dysfunction</p> Signup and view all the answers

    Which treatment is classified as medical management for congestive left-sided heart failure?

    <p>Oxygen therapy</p> Signup and view all the answers

    What factor might influence a dog's prognosis after surgical intervention for congenital heart defects?

    <p>Presence of clinical signs before surgery</p> Signup and view all the answers

    Which clinical finding might indicate the presence of heart failure related to tachycardia?

    <p>Enlargement of all four heart chambers</p> Signup and view all the answers

    What is a characteristic of the arrhythmias induced by Adriamycin treatment in dogs?

    <p>Accompanied by myocardial failure</p> Signup and view all the answers

    What characterizes hypertrophic cardiomyopathy in dogs?

    <p>Idiopathic concentric hypertrophy of the ventricle</p> Signup and view all the answers

    Which treatment option is appropriate for managing atrial fibrillation in dogs?

    <p>Antiarrhythmic medication such as sotalol</p> Signup and view all the answers

    What is a common prognosis for dogs with tachycardia-induced complications?

    <p>Favorable with adequate heart rate control</p> Signup and view all the answers

    Which symptom is less likely to be seen in infectious myocarditis in dogs?

    <p>Favorable prognosis</p> Signup and view all the answers

    Which of the following is NOT a secondary cause to rule out for ventricular hypertrophy?

    <p>Degenerative mitral disease</p> Signup and view all the answers

    How is endocrine-related ventricular hypertrophy typically managed in dogs?

    <p>Thyroid supplementation</p> Signup and view all the answers

    What may increase the risk of sudden death in dogs with cardiovascular disorders?

    <p>High-risk arrhythmias</p> Signup and view all the answers

    What is the most effective method to alleviate dyspnea in dogs with heart failure?

    <p>Administration of ACE inhibitors</p> Signup and view all the answers

    Which clinical signs may indicate the presence of right-sided heart failure?

    <p>Weight loss and ascites</p> Signup and view all the answers

    What is a common physical examination finding you might expect during an assessment of a dog with tricuspid regurgitation?

    <p>Jugular venous distension</p> Signup and view all the answers

    Which of the following breeds is least likely to be associated with fibro-fatty infiltration of the right ventricle?

    <p>German Shepherd</p> Signup and view all the answers

    Which of the following clinical signs is NOT commonly associated with heart failure in small breed dogs?

    <p>Weight gain</p> Signup and view all the answers

    During a physical examination, which finding would indicate potential pulmonary hypertension?

    <p>Jugular venous distension with ascites</p> Signup and view all the answers

    What diagnostic method is primarily used to identify left atrial enlargement in affected dogs?

    <p>Echocardiogram</p> Signup and view all the answers

    Which of the following might NOT be a direct result of right-sided heart failure?

    <p>Heart murmur</p> Signup and view all the answers

    In what situation would you expect to hear a mid-systolic click during heart examination?

    <p>When assessing mitral regurgitation</p> Signup and view all the answers

    What does positive hepatojugular reflex typically indicate?

    <p>Right-sided heart failure</p> Signup and view all the answers

    What is a potential outcome for patients with severe heart conditions, characterized by clinical signs?

    <p>Shortened lifespan and risk of sudden death</p> Signup and view all the answers

    Which of the following is a characteristic feature of mitral valve dysplasia in affected breeds?

    <p>Exercise intolerance</p> Signup and view all the answers

    Which prognosis is associated with moderate cardiomyopathy cases?

    <p>Clinical signs may develop</p> Signup and view all the answers

    What specific finding might be noted on an echocardiogram in dogs with tricuspid valve dysplasia?

    <p>Right ventricular enlargement</p> Signup and view all the answers

    What abnormal finding in an ECG may suggest right atrial enlargement?

    <p>Tall P waves in lead II</p> Signup and view all the answers

    Which type of diagnostic imaging might reveal caudal vena cava enlargement due to heart conditions?

    <p>Thoracic radiographs</p> Signup and view all the answers

    What commonality exists between tricuspid valve dysplasia and mitral valve dysplasia?

    <p>Commonly affect large breeds</p> Signup and view all the answers

    Which clinical sign is least likely to be observed in a dog with myocardial disease?

    <p>Normal pulse quality</p> Signup and view all the answers

    What is a common diagnostic tool used to evaluate ventricular septal defects in dogs?

    <p>Echocardiogram</p> Signup and view all the answers

    Which of the following breed(s) is NOT commonly associated with dilated cardiomyopathy?

    <p>Beagle</p> Signup and view all the answers

    In cats, which of the following types of cardiomyopathy is least commonly associated?

    <p>Dilated cardiomyopathy</p> Signup and view all the answers

    What does successful closure of a left-to-right shunt generally require?

    <p>Surgical intervention</p> Signup and view all the answers

    Which clinical sign is most indicative of aortic insufficiency during a physical examination?

    <p>Diastolic left basilar murmur</p> Signup and view all the answers

    Which finding on an electrocardiogram may suggest left ventricular enlargement?

    <p>Tall R waves in lead II</p> Signup and view all the answers

    Which notable residual effect may persist even after treatment for congenital heart disease?

    <p>Structural damage to the esophagus</p> Signup and view all the answers

    What does an echocardiogram revealing global left ventricular wall thickening of more than 6 mm indicate?

    <p>Cardiomyopathy</p> Signup and view all the answers

    Which of the following physical examination findings might suggest the presence of a diastolic dysfunction?

    <p>Gallop rhythm</p> Signup and view all the answers

    Which diagnostic test would most likely show evidence of pleural effusion in an affected dog?

    <p>Thoracic radiographs</p> Signup and view all the answers

    What kind of arrhythmias might be observed during an electrocardiogram in a dog with left atrial enlargement?

    <p>Supraventricular arrhythmias</p> Signup and view all the answers

    What is the most significant implication of decreased fractional shortening observed in an echocardiogram?

    <p>Cardiac dilation</p> Signup and view all the answers

    Which symptom is most commonly associated with sudden death in dogs experiencing heart issues?

    <p>Hypothermia</p> Signup and view all the answers

    Which finding might be evident during a physical examination of a dog with significant left and/or right atrial enlargement?

    <p>Jugular venous distension</p> Signup and view all the answers

    Which of the following is a likely consequence observed on thoracic radiographs in cases of severe heart disease?

    <p>Pulmonary edema</p> Signup and view all the answers

    Which of the following accurately describes the impact of pulmonic stenosis in Tetralogy of Fallot?

    <p>It creates an obstruction to blood flow into the pulmonary artery.</p> Signup and view all the answers

    What is a common clinical consequence of Tetralogy of Fallot related to blood composition?

    <p>Polycythemia resulting from chronic hypoxemia.</p> Signup and view all the answers

    Which breed is significantly associated with the occurrence of Tetralogy of Fallot?

    <p>Keeshond</p> Signup and view all the answers

    Which procedure can create a temporary solution to improve blood flow in Tetralogy of Fallot patients?

    <p>Blalock Taussig shunt connecting the left subclavian artery to the pulmonary artery.</p> Signup and view all the answers

    Which treatment is NOT typically considered in the medical management of Tetralogy of Fallot?

    <p>Exercise tolerance training for improved cardiac output.</p> Signup and view all the answers

    What characterizes the genetic inheritance pattern of Tetralogy of Fallot?

    <p>Simple autosomal recessive trait.</p> Signup and view all the answers

    Which of the following clinical signs might be observed in a dog with Tetralogy of Fallot?

    <p>Lethargy, syncope, and exercise intolerance.</p> Signup and view all the answers

    Which of these is NOT a component of the clinical management for Tetralogy of Fallot?

    <p>Immediate surgical intervention for all diagnosed cases.</p> Signup and view all the answers

    What is the term used for the resistance to blood flow through the systemic arterioles?

    <p>Systemic vascular resistance</p> Signup and view all the answers

    Which diagnostic test is used to analyze the electrical activity and rhythm of the heart?

    <p>Electrocardiography</p> Signup and view all the answers

    Which condition is characterized by increased ventricular wall thickness due to pressure overload?

    <p>Concentric hypertrophy</p> Signup and view all the answers

    What does an elevation of norepinephrine levels typically indicate?

    <p>A decrease in cardiac output</p> Signup and view all the answers

    Which diagnostic method is primarily used to assess heart size and shape in patients suspected of heart failure?

    <p>Thoracic radiographs</p> Signup and view all the answers

    Which of the following conditions is NOT typically associated with eccentric hypertrophy?

    <p>Pulmonary hypertension</p> Signup and view all the answers

    What type of hypertrophy is most commonly caused by systemic hypertension?

    <p>Concentric hypertrophy</p> Signup and view all the answers

    Which diagnostic procedure involves placing catheters into peripheral vessels for heart evaluation?

    <p>Cardiac catheterization and angiography</p> Signup and view all the answers

    Which physical examination finding is characterized by an abnormal pulse quality that may suggest heart dysfunction?

    <p>Normal to decreased pulse quality</p> Signup and view all the answers

    What laboratory analysis is primarily used to evaluate thyroid function in suspected cardiac patients?

    <p>Thyroid panel (thyroxine [T4])</p> Signup and view all the answers

    Which symptom is most indicative of fluid accumulation due to heart failure?

    <p>Dyspnea</p> Signup and view all the answers

    Which condition is characterized by the presence of congestive heart failure (CHF)?

    <p>Left- and right-sided heart failure</p> Signup and view all the answers

    What finding on an echocardiogram is likely indicative of left atrial enlargement?

    <p>Enlarged pulmonary veins</p> Signup and view all the answers

    What is a classic sign of volume overload associated with cardiac abnormalities?

    <p>Ascites</p> Signup and view all the answers

    Which treatment option is commonly under investigation for managing cardiac conditions?

    <p>Beta-blockers</p> Signup and view all the answers

    What would likely increase as a physiological response due to severe heart conditions?

    <p>Norepinephrine levels</p> Signup and view all the answers

    Which treatment is NOT typically used in managing congestive heart failure (CHF)?

    <p>Therapeutic ultrasound</p> Signup and view all the answers

    What is the expected life span of an adult heartworm?

    <p>Approximately 5 years</p> Signup and view all the answers

    What characteristic distinguishes Dirofilaria immitis microfilaria from Dipetalonema reconditum using a modified Knott's test?

    <p>Dirofilaria immitis has a straight body</p> Signup and view all the answers

    In which scenario might clinical signs of heartworm disease remain unnoticed?

    <p>In asymptomatic dogs with no previous history</p> Signup and view all the answers

    Which option accurately describes microfilaria transmission in dogs?

    <p>Microfilaria can be passed from mother to offspring</p> Signup and view all the answers

    What is a typical clinical sign of severe heartworm disease?

    <p>Severe lethargy</p> Signup and view all the answers

    What is indicated by a prognosis classified as guarded to poor in heart disease cases?

    <p>There is limited expectation for recovery or improvement</p> Signup and view all the answers

    What physical examination finding may indicate the presence of enlarged and tortuous caudal structures?

    <p>Distended abdomen with fluid accumulation</p> Signup and view all the answers

    What is the maximum lifespan of an adult heartworm?

    <p>Less than 4 years</p> Signup and view all the answers

    Which clinical sign is most likely associated with heartworm infection?

    <p>Anorexia</p> Signup and view all the answers

    What is a recommended medication for monthly heartworm prevention?

    <p>Selamectin</p> Signup and view all the answers

    Which method is advised for managing clinical signs of heartworm disease?

    <p>Corticosteroids</p> Signup and view all the answers

    Which heartworm treatment is associated with significant adverse effects?

    <p>Melarsomine</p> Signup and view all the answers

    What is the typical heartworm burden in infected dogs?

    <p>One to nine worms</p> Signup and view all the answers

    Which physical examination finding might suggest heart disease?

    <p>Gallop rhythm</p> Signup and view all the answers

    What is typically true about the prognosis for heartworm-infected dogs?

    <p>Generally guarded</p> Signup and view all the answers

    What is the primary characteristic of Ivermectin when used for heartworm treatment?

    <p>It is administered as a single IM injection followed by another IM injection after a month.</p> Signup and view all the answers

    What is one reason why Ivermectin is not routinely recommended as adulticide therapy?

    <p>It can cause ongoing pulmonary and myocardial damage.</p> Signup and view all the answers

    What is the consequence of administering melarsomine injections in heartworm treatment?

    <p>Adverse effects usually occur 5 to 7 days after injection.</p> Signup and view all the answers

    In what scenario is surgery recommended for heartworm treatment?

    <p>When caval syndrome is present with heartworms in the right atrium.</p> Signup and view all the answers

    Which of the following is a requirement for treatment with Ivermectin?

    <p>Dogs must have clinical signs and abnormal diagnostic tests.</p> Signup and view all the answers

    Which statement is true about the administration schedule of Ivermectin?

    <p>An initial IM injection is followed by two IM injections 24 hours apart after 4 to 6 weeks.</p> Signup and view all the answers

    How does prolonged administration of Ivermectin affect heartworm treatment?

    <p>It may lead to improvement over a period of approximately 31 months.</p> Signup and view all the answers

    What is a significant drawback of using melarsomine compared to Ivermectin?

    <p>It necessitates a longer period of confinement post-administration.</p> Signup and view all the answers

    Study Notes

    Right Ventricular Endocardiosis

    • Characterized by fatty or fibrofatty infiltration of the right ventricle
    • Common breeds: dachshund, miniature poodle, cocker spaniel, Pomeranian, Miniature schnauzer, Boston terrier, Chihuahua
    • May be normal, exercise intolerance, lethargy, anorexia, weight loss, right-sided heart failure (cough, dyspnea, ascites), syncope, sudden death
    • Physical exam findings: systolic left apical murmur with mitral regurgitation, systolic right heart murmur with tricuspid regurgitation, mid-systolic click, normal pulse quality, arrhythmia, gallop, dyspnea, normal to pale mucous membrane color, ascites, positive hepatojugular reflex, jugular venous distension, hypothermia
    • Diagnosis: echocardiogram, EKG, thoracic radiographs

    ### Pulmonary Hypertension

    • Increased pulmonary artery pressure
    • May be primary or secondary
    • Secondary causes: heartworm disease, pulmonary thromboembolism, mitral valve disease, tricuspid valve disease, left ventricular failure, lung diseases (fibrosis, pulmonary edema, pneumonia),
    • Clinical signs: May be normal, exercise intolerance, lethargy, anorexia, weight loss, right-sided heart failure (cough, dyspnea, ascites), syncope, sudden death
    • Physical exam findings: systolic left apical murmur with mitral regurgitation, systolic right heart murmur with tricuspid regurgitation, mid-systolic click, normal pulse quality, arrhythmia, gallop, dyspnea, normal to pale mucous membrane color, ascites, positive hepatojugular reflex, jugular venous distension, hypothermia, signs of right-sided heart failure if tricuspid endocardiosis or pulmonary hypertension (ascites, positive hepatojugular reflex, jugular venous distension)
    • Diagnosis: Echocardiogram, EKG, thoracic radiographs

    Patent Ductus Arteriosus (PDA)

    • Persistent connection between the aorta and the pulmonary artery
    • Blood shunts from the aorta to the pulmonary artery
    • Spontaneous closure rarely occurs
    • Typically shunt left to right
    • Common breeds: English springer spaniel, English Bulldog
    • Clinical signs: May be normal, exercise intolerance, lethargy, cough, dyspnea
    • Physical exam findings: Systolic right sternal or left basilar murmur (Loud murmurs are associated with small ventricular septal defects), Diastolic left basilar murmur associated with aortic regurgitation if aortic valve leaflet prolapses into USD, Normal pulse quality
    • Diagnosis: Echocardiogram (Left ventricular enlargement, left atrial enlargement, ventricular septal defect, aortic insufficiency), EKG (Tall R waves in lead II suggestive of left ventricular enlargement, Wide P waves in lead II suggestive of left atrial enlargement), Thoracic radiographs (Normal in dogs with small septal defects), angiography, esophageal endoscopy
    • Treatment: Surgical ligation of the ligamentum arteriosum
    • Prognosis: Good to guarded; Residual esophageal functional and structural damage may persist

    ### Ventricular Septal Defect (VSD)

    • Hole in the septum between the right and left ventricles
    • May be small or large
    • Diagnosis: Echocardiogram (Right ventricular enlargement, right atrial enlargement, tricuspid regurgitation, pleural effusion, pericardial effusion), EKG (Sinus arrhythmia, Sinus tachycardia. Tall R waves in lead II suggestive of left ventricular enlargement, Wide P waves in lead II suggestive of left atrial enlargement), Thoracic radiographs (Normal in dogs with small septal defects, Right ventricular enlargement, right atrial enlargement, pulmonary artery enlargement, blunting of the caudal pulmonary arteries, right ventricular enlargement, bronchointerstitial to alveolar pulmonary pattern), Electrocardiography (Deep S waves in leads I, II, III, aVf suggestive of right ventricular enlargement, Right axis deviation, Tall P waves in lead II suggestive of right atrial enlargement), Echocardiogram (May be normal, Right ventricular enlargement, Main pulmonary artery enlargement, Tricuspid regurgitation, Pulmonic regurgitation, Heartworms within the right atrium, ventricle, or pulmonary artery)
    • Clinical signs: May be normal, exercise intolerance, lethargy, cough, dyspnea, abnormal bronchovesicular sounds, systolic right heart murmur of tricuspid regurgitation. Caused by elevated right ventricular pressures secondary to pulmonary hypertension, the physical presence of the heartworms across the tricuspid valve, or tricuspid valve endocardiosis, arrhythmias, split-second heart sound, fever, right-sided heart failure (ascites, positive hepatojugular reflex, jugular venous distension)
    • Caval syndrome: occurs when the heartworms migrate into the right atrium, right ventricle and vena cava; Patients may have port wine-colored urine with hemoglobinuria, Patients often develop renal and hepatic failure, congestive right heart failure, and disseminated intravascular coagulation
    • Diagnosis: CBC (May be normal, Anemia, Neutrophilia)

    ### Dilated Cardiomyopathy (DCM)

    • Heritable in some breeds: boxer, Doberman pinscher, Great Dane, Newfoundland
    • More common in male dogs
    • Preclinical: Denoted by the presence of left ventricular dilation, left ventricular systolic dysfunction, left ventricular enlargement, normal, increased, or decreased systolic function, normal left ventricular wall thickness, thickened valve leaflets, prolapse or flail of the valve leaflets, mitral regurgitation, normal transaortic and transpulmonic velocities, signs of right heart enlargement with tricuspid endocardiosis or pulmonary hypertension (right atrial enlargement, right ventricular enlargement, tricuspid regurgitation, pulmonic regurgitation, pulmonary artery enlargement)
    • Diagnosis: Echocardiogram (Right ventricular enlargement, right atrial enlargement, tricuspid regurgitation, pleural effusion, pericardial effusion)
    • Clinical signs: May be normal, exercise intolerance, lethargy, cough, dyspnea, abnormal bronchovesicular sounds, systolic right heart murmur of tricuspid regurgitation. Caused by elevated right ventricular pressures secondary to pulmonary hypertension, the physical presence of the heartworms across the tricuspid valve, or tricuspid valve endocardiosis, arrhythmias, split-second heart sound, fever, right-sided heart failure (ascites, positive hepatojugular reflex, jugular venous distension)
    • EKG: Sinus arrhythmia, Sinus tachycardia, Tall R waves in lead II suggestive of left ventricular enlargement, Wide P waves in lead II suggestive of left atrial enlargement
    • Treatment: Digoxin, furosemide, pimobendan, angiotensin-converting enzyme (ACE) inhibitors, spironolactone, vasodilators, antiarrhythmic therapy, Surgery: Valvular repair or replacement (requires special equipment, costly, not readily available)
    • Prognosis: Dependent on progression and severity of the disease; Cavalier King Charles spaniels may have a faster rate of progression

    Valvular Endocardiosis

    • Incidence is higher in large breed dogs and dogs with congenital heart disease (aortic stenosis and ventricular septal defects)
    • Most common valves affected are aortic, mitral
    • Most common infectious organisms are Escherichia coli, Staphylococcus aureus, Streptococcus spp.
    • May be normal
    • Clinical signs: May be normal, exercise intolerance, lethargy, cough, dyspnea, abnormal bronchovesicular sounds, systolic right heart murmur of tricuspid regurgitation. Caused by elevated right ventricular pressures secondary to pulmonary hypertension, the physical presence of the heartworms across the tricuspid valve, or tricuspid valve endocardiosis, arrhythmias, split-second heart sound, fever, right-sided heart failure (ascites, positive hepatojugular reflex, jugular venous distension)
    • Physical exam findings: systolic left apical murmur with mitral regurgitation, systolic right heart murmur with tricuspid regurgitation, mid-systolic click, normal pulse quality, arrhythmia, gallop, dyspnea, normal to pale mucous membrane color, ascites, positive hepatojugular reflex, jugular venous distension, hypothermia, signs of right-sided heart failure if tricuspid endocardiosis or pulmonary hypertension (ascites, positive hepatojugular reflex, jugular venous distension)
    • Diagnosis: EKG (Sinus arrhythmia, Sinus tachycardia, Tall R waves in lead II suggestive of left ventricular enlargement, Wide P waves in lead II suggestive of left atrial enlargement), Thoracic radiographs (Normal in dogs with small septal defects, Right ventricular enlargement, right atrial enlargement, pulmonary artery enlargement, blunting of the caudal pulmonary arteries, right ventricular enlargement, bronchointerstitial to alveolar pulmonary pattern), Echocardiogram (May be normal, Right ventricular enlargement, Main pulmonary artery enlargement, Tricuspid regurgitation, Pulmonic regurgitation, Heartworms within the right atrium, ventricle, or pulmonary artery)
    • Treatment: Antibiotics, Surgery: Valve repair or replacement (requires special equipment, costly, not readily available)
    • Prognosis: Good to guarded; Dependent on progression and severity of the disease; Cavalier King Charles spaniels may have a faster rate of progression

    ### Heartworm Disease

    • Caused by the parasitic nematode Dirofilaria immitis
    • Mosquito-borne
    • Clinical signs: May be normal, exercise intolerance, lethargy, cough, dyspnea, abnormal bronchovesicular sounds, systolic right heart murmur of tricuspid regurgitation. Caused by elevated right ventricular pressures secondary to pulmonary hypertension, the physical presence of the heartworms across the tricuspid valve, or tricuspid valve endocardiosis, arrhythmias, split-second heart sound, fever, right-sided heart failure (ascites, positive hepatojugular reflex, jugular venous distension), Caval syndrome (port wine-colored urine with hemoglobinuria, renal and hepatic failure, congestive right heart failure, and disseminated intravascular coagulation)
    • Physical exam findings: systolic left apical murmur with mitral regurgitation, systolic right heart murmur with tricuspid regurgitation, mid-systolic click, normal pulse quality, arrhythmia, gallop, dyspnea, normal to pale mucous membrane color, ascites, positive hepatojugular reflex, jugular venous distension, hypothermia, signs of right-sided heart failure if tricuspid endocardiosis or pulmonary hypertension (ascites, positive hepatojugular reflex, jugular venous distension)
    • Diagnosis: Thoracic radiographs (Right ventricular enlargement, right atrial enlargement, pulmonary artery enlargement, blunting of the caudal pulmonary arteries, right ventricular enlargement, bronchointerstitial to alveolar pulmonary pattern), Echocardiogram (May be normal, Right ventricular enlargement, Main pulmonary artery enlargement, Tricuspid regurgitation, Pulmonic regurgitation, Heartworms within the right atrium, ventricle, or pulmonary artery), CBC (May be normal, Anemia, Neutrophilia)
    • Treatment: Heartworm medication, Surgery: Surgical removal of the adult worms
    • Prognosis: Good to guarded; Dependent on progression and severity of the disease; Cavalier King Charles spaniels may have a faster rate of progression

    Hypertrophic Cardiomyopathy (HCM)

    • Thickening of the ventricular walls
    • May be inherited or idiopathic
    • Common breeds: Maine Coon cats, Ragdoll cats, Sphynx cats, Persian cats, Siamese cats, Abyssinian cats, American Shorthair cats
    • Clinical signs: May be normal, exercise intolerance, lethargy, cough, dyspnea, abnormal bronchovesicular sounds, systolic right heart murmur of tricuspid regurgitation. Caused by elevated right ventricular pressures secondary to pulmonary hypertension, the physical presence of the heartworms across the tricuspid valve, or tricuspid valve endocardiosis, arrhythmias, split-second heart sound, fever, right-sided heart failure (ascites, positive hepatojugular reflex, jugular venous distension), Caval syndrome (port wine-colored urine with hemoglobinuria, renal and hepatic failure, congestive right heart failure, and disseminated intravascular coagulation)
    • Physical exam findings: systolic left apical murmur with mitral regurgitation, systolic right heart murmur with tricuspid regurgitation, mid-systolic click, normal pulse quality, arrhythmia, gallop, dyspnea, normal to pale mucous membrane color, ascites, positive hepatojugular reflex, jugular venous distension, hypothermia, signs of right-sided heart failure if tricuspid endocardiosis or pulmonary hypertension (ascites, positive hepatojugular reflex, jugular venous distension)
    • Diagnosis: Echocardiogram (Right ventricular enlargement, right atrial enlargement, tricuspid regurgitation, pleural effusion, pericardial effusion)
    • Treatment: Diuretics, antiarrhythmic drugs, vasodilators, surgery
    • Prognosis: Guarded; Dependent on progression and severity of the disease; Caval King Charles spaniels may have a faster rate of progression

    Restrictive Cardiomyopathy

    • Stiffening of the ventricular walls
    • May be inherited or idiopathic
    • Common breeds: Maine Coon cats, Ragdoll cats, Sphynx cats, Persian cats, Siamese cats, Abyssinian cats, American Shorthair cats
    • Clinical signs: May be normal, exercise intolerance, lethargy, cough, dyspnea, abnormal bronchovesicular sounds, systolic right heart murmur of tricuspid regurgitation. Caused by elevated right ventricular pressures secondary to pulmonary hypertension, the physical presence of the heartworms across the tricuspid valve, or tricuspid valve endocardiosis, arrhythmias, split-second heart sound, fever, right-sided heart failure (ascites, positive hepatojugular reflex, jugular venous distension), Caval syndrome (port wine-colored urine with hemoglobinuria, renal and hepatic failure, congestive right heart failure, and disseminated intravascular coagulation)
    • Physical exam findings: systolic left apical murmur with mitral regurgitation, systolic right heart murmur with tricuspid regurgitation, mid-systolic click, normal pulse quality, arrhythmia, gallop, dyspnea, normal to pale mucous membrane color, ascites, positive hepatojugular reflex, jugular venous distension, hypothermia, signs of right-sided heart failure if tricuspid endocardiosis or pulmonary hypertension (ascites, positive hepatojugular reflex, jugular venous distension)
    • Diagnosis: Echocardiogram (Right ventricular enlargement, right atrial enlargement, tricuspid regurgitation, pleural effusion, pericardial effusion)
    • Treatment: Diuretics, antiarrhythmic drugs, vasodilators, surgery
    • Prognosis: Guarded; Dependent on progression and severity of the disease; Cavalier King Charles spaniels may have a faster rate of progression

    Arrythmogenic Right Ventricular Cardiomyopathy (ARVC)

    • Inherited disorder
    • Characterized by fatty degeneration and fibrosis of the right ventricle
    • Common breeds: Boxer, Doberman Pinscher, Great Dane, Newfoundland
    • Clinical signs: May be normal, exercise intolerance, lethargy, cough, dyspnea, abnormal bronchovesicular sounds, systolic right heart murmur of tricuspid regurgitation. Caused by elevated right ventricular pressures secondary to pulmonary hypertension, the physical presence of the heartworms across the tricuspid valve, or tricuspid valve endocardiosis, arrhythmias, split-second heart sound, fever, right-sided heart failure (ascites, positive hepatojugular reflex, jugular venous distension), Caval syndrome (port wine-colored urine with hemoglobinuria, renal and hepatic failure, congestive right heart failure, and disseminated intravascular coagulation)
    • Physical exam findings: systolic left apical murmur with mitral regurgitation, systolic right heart murmur with tricuspid regurgitation, mid-systolic click, normal pulse quality, arrhythmia, gallop, dyspnea, normal to pale mucous membrane color, ascites, positive hepatojugular reflex, jugular venous distension, hypothermia, signs of right-sided heart failure if tricuspid endocardiosis or pulmonary hypertension (ascites, positive hepatojugular reflex, jugular venous distension)
    • Diagnosis: Echocardiogram (Right ventricular enlargement, right atrial enlargement, tricuspid regurgitation, pleural effusion, pericardial effusion)
    • Treatment: Antiarrhythmic drugs, implantable cardioverter-defibrillator (ICD)
    • Prognosis: Guarded; Dependent on progression and severity of the disease; Cavalier King Charles spaniels may have a faster rate of progression

    ### Diagnostic Tests

    • Echocardiography: Ultrasound of the heart used to evaluate structure and function
    • Electrocardiography: Records the electrical activity of the heart for analysis of heart rate and rhythm, conduction abnormalities, and chamber enlargement patterns
    • Holter monitor: Records an electrocardiogram (ECG) over an extended period
    • Thoracic radiographs: Used to evaluate heart size and shape, to assess pulmonary and mediastinal structures, and to evaluate for congestive heart failure (CHF)
    • Blood pressure: Systolic; mean and diastolic systemic arterial pressure can be measured invasively (direct) or noninvasively (indirect)
    • Cardiac catheterization and angiography: Catheters placed into peripheral vessels are used to evaluate

    Cardiomyopathy

    • Positive inotropic support
      • Treatment for cardiomyopathy
    • ACE inhibitor
      • Treatment for cardiomyopathy
    • CHF
      • Treatment for cardiomyopathy
      • Oxygen, diuretics, pleurocentesis, abdominocentesis, antiarrhythmic therapy
    • Antiarrhythmic therapy
      • Treatment for cardiomyopathy
    • Thromboembolism
      • Treatment for cardiomyopathy
      • Aspirin, clopidogrel, pain medication, physical therapy
    • Prognosis
      • Mild: Favorable; rarely develop clinical signs
      • Moderate: May develop clinical signs
      • Severe: Develop clinical signs; prognosis is poor

    Arrhythmogenic Right Ventricular Cardiomyopathy In Cats

    • Cardiac output is the combination of stroke volume and heart rate.
    • Systemic vascular resistance is the resistance to blood flow through the systemic arterioles.
    • Blood pressure is a combination of cardiac output and systemic vascular resistance.
    • Eccentric hypertrophy: Dilated atrial or ventricular chambers with normal to decreased wall thickness caused by a volume overload.
      • Dilated cardiomyopathy
      • Valvular endocardiosis
      • Patent ductus arteriosus (PDA)
      • Ventricular septal defect
      • Atrial septal defect (ASD)
    • Concentric hypertrophy: Ventricular wall thickening caused by a pressure overload.
      • Systemic hypertension
      • Pulmonary hypertension
      • Pulmonic stenosis
      • Aortic stenosis

    Valvular Endocardiosis

    • Common acquired heart disease in middle-aged to older dogs
    • Occurs with less frequency in cats
    • Myxomatous degeneration of the atrioventricular valves (mitral valve more frequently than tricuspid valve)
    • Progression to heart failure is highly variable
    • Acute decompensation occurs with chordae tendinae rupture, left atrial rupture, and the onset of arrhythmias.
    • More common in small breed dogs, but does occur in large and giant breeds
    • Common breeds: Cavalier King Charles spaniel.
    • Norepinephrine levels increase in response to a decrease in cardiac output resulting in tachycardia and vasoconstriction.

    Diagnostic Tests

    • Echocardiography: Ultrasound of the heart used to evaluate structure and function
    • Electrocardiography: Records the electrical activity of the heart for analysis of hear rate and rhythm, conduction abnormalities, and chamber enlargement patterns
    • Holter monitor: Records an electocardiogram (ECG) over an extended period.
    • Thoracic radiographs: Used to evaluate heart size and shape, to assess pulmonary and mediastinal structures, and to evaluate for CHF
    • Blood pressure: Systolic, mean, and diastolic systemic arterial pressure can be measured invasively (direct) or noninvasively (indirect)
    • Cardiac catheterization and angiography: Catheters placed into peripheral vessels are used to evaluate heart and blood vessels

    Patent Ductus Arteriosus (PDA)

    • Results from congenital lack of ductal smooth muscle
    • Typically left to right shunting
    • Common breeds: Miniature poodle, Maltese, German shepherd, Yorkshire terrier, Shetland sheepdog, collie Pomeranian, Labrador retriever, bichon frise
    • Clinical signs: May be normal; exercise intolerance, lethargy, cough, dyspnea
    • Physical examination
      • Continuous left basilar murmur
      • Systolic left apical murmur of mitral regurgitation
      • Increased (hyperkinetic) pulse quality results from a large difference in systolic and diastolic pulse pressure
      • Dyspnea
    • Diagnosis
      • Echocardiogram:
        • Left ventricular enlargement
        • Left atrial enlargement
        • Continuous color flow within the main pulmonary artery
        • Visualization of the PDA. Typically funnel shaped with narrowing at the pulmonary artery side
        • Hypertrophic cardiomyopathy in cats
          • Characterized by concentric hypertrophy of the ventricle.
          • Hypertrophic obstructive cardiomyopathy (HOCM) occurs when there is a dynamic obstruction to blood entering the left ventricular outflow tract secondary to systolic anterior motion of the mitral valve
          • Inheritance patterns: Autosomal dominant in Maine Coon cats
          • Common breeds: Maine Coon, Persian ragdoll, American shorthair, domestic shorthair, domestic longhair
          • Secondary causes of ventricular hypertrophy
            • Aortic stenosis
            • Systemic hypertension
            • Hyperthyroidism
            • Significant dehydration
            • Infiltrative neoplasia
            • Acromegaly
          • Clinical signs: May be normal, exercise intolerance, and include cough, anorexia, and fever

    Atrial Septal Defect (ASD)

    • Occurs in dogs and cats
    • Typically shunts left to right
    • Common breeds: Boxer, standard poodle
    • Clinical signs: May be normal; exercise intolerance, lethargy, syncope, right heart sided heart that failure with large defects, ascites
    • Physical examination
      • Systolic left basilar murmur
      • Split second heart sound
      • Normal pulse quality
      • Right-sided heart failure with large defects: Ascites, jugular venous distension, positive hepatojugular reflex
    • Diagnosis
      • Echocardiogram
        • Right ventricular enlargement
        • Right atrial enlargement
        • ASD
      • Electrocardiography
        • Deep S waves in leads I, II, III, aVf

    Dilated Cardiomyopathy

    • Taurine deficiency: Favorable with taurine supplementation
    • L-carnitine deficiency: Favorable with carnitine supplementation
    • Idiopathic: Poor
    • Boxer: Present primarily with arrhythmias
    • Cocker spaniels: Associated with taurine and L-carnitine deficiency
    • Golden retriever:
      • Canine x-linked muscular dystrophy
      • Myocardial lesions develop before 1 year of age
      • Prognosis is guarded to poor
    • Great Dane: X-linked inheritance pattern
    • Irish wolfhound:
      • Frequently present with atrial fibrillation
      • Often have biventricular heart failure
    • Adulticidal:
      • Melarsomine (Immiticide)
        • Arsenic-based compound
        • Safer than its predecessor, thiacetarsamide
        • Standard protocol
          • Consists of two intramuscular (IM) injections 24 hours apart
          • Seroconversion to a negative antigen test reaches approximately 75%
          • May be selected in cases with financial issues or for dogs without clinical signs and with essentially normal diagnostic test (thoracic radiographs and blood work)
        • Split protocol (Preferred):
          • Consists of 3 IM injections
          • 1st given at the start of treatment
          • 2nd given 2 weeks after the 1st treatment
          • 3rd given 2 weeks after the 2nd treatment
          • Seroconversion to a negative antigen test reaches approximately 90%
          • May be selected in cases with financial issues or for dogs without clinical signs and with essentially normal diagnostic test (thoracic radiographs and blood work) - At home care: - Strict cage confinement for 4 weeks with the standard protocol and 8 weeks with the split protocol - Concurrent administration of anti-inflammatory corticosteroids - Aspirin therapy is not recommended - Concurrent corticosteroid and nonsteroidal anti-inflammatory medication is contraindicated - Recheck heartworm antigen test 4 to 6 months following treatment

    Systolic Left Basilar Murmur

    • Positive inotropic support and Nitroglycerin ointment can be used as treatment
    • ACE Inhibitors can be used as both treatment for preclinical conditions and patients with congestive heart failure

    Diastolic Left Basilar Murmur

    • Can be associated with significant pulmonic valvular regurgitation

    Prognosis for Patent Ductus Arteriosus (PDA)

    • Small PDA: Favorable, might not develop clinical signs
    • Moderate to large PDA: Develop clinical signs, favorable with ductal occlusion-ligation; shortened life span without treatment

    Right-to-left Shunting PDA

    • Attributed to increased pulmonary vascular resistance
    • Patients develop hypoxemia, exercise intolerance, collapse, tachypnea, dyspnea, and ascites
    • Polycythemia results from hypoxemia and managed with phlebotomy or hydroxyurea
    • PDA closure is contraindicated and will result in severe hypoxemia and death
    • Prognosis is poor

    Pulmonic Stenosis

    • Valvular pulmonic stenosis is a common congenital heart disease in dogs
    • Severity can increase until a dog reaches mature body weight
    • An aberrant left coronary artery encircles the right ventricular outflow tract and pulmonic valve causing pulmonic stenosis, this occurs most often in the English bulldog and boxer

    Diagnosis of Pulmonic Stenosis

    • Echocardiogram:
      • Right ventricular hypertrophy
      • Interventricular septal flattening
      • Right atrial enlargement
      • Poststenotic dilation of main pulmonary artery
      • Thickened pulmonic valve leaflets
      • Restricted motion of pulmonic valve leaflets
      • Pulmonic regurgitation
      • Elevated peak transpulmonic velocities
      • Hypoplastic pulmonic valve annulus
      • Aberrant coronary artery
    • Electrocardiogram:
      • Deep S waves in leads I, II, III, aVf suggestive of right ventricular enlargement
      • Right axis deviation
      • Tall P waves in lead II suggestive of right atrial enlargement
    • Thoracic radiographs:
      • Normal in dogs with mild disease
      • Right ventricular enlargement
      • Right atrial enlargement
      • Poststenotic dilation of main pulmonary artery
      • Enlarged caudal vena cava

    Treatment of Pulmonic Stenosis

    • Balloon valvuloplasty:
      • For valvular pulmonic stenosis
      • Hypertrophic cardiomyopathy in cats
        • Taurine deficiency: Favorable with taurine supplementation
        • L-carnitine deficiency: Favorable with carnitine supplementation
      • Idiopathic: Poor
    • Boxer: Present primarily with arrhythmias
    • Cocker spaniels: Associated with taurine and L-carnitine deficiency
    • Golden retriever:
      • Canine X-linked muscular dystrophy
      • Myocardial lesions develop before 1 year of age
      • Prognosis is guarded to poor
    • Great Dane: X-linked inheritance pattern
    • Irish wolfhound:
      • Frequently present with atrial fibrillation
      • Often have biventricular heart failure

    Treatment of Hypertrophic Cardiomyopathy

    • Medical management:
      • Preclinical:
        • No medication shown to delay the progression of the disease
        • ACE inhibitors frequently prescribed
        • The use of beta-blockers is under investigation
      • CHF:
        • Oxygen
        • Diuretics
        • Positive inotropic support
        • Nitroglycerin ointment
        • ACE inhibitor
        • Pleurocentesis
        • Abdominocentesis
      • Mainstem bronchial compression:
        • Cough suppressant such as hydrocodone, butorphanol, or dextromethorphan
        • Bronchodilator such as theophylline
      • Systemic hypertension: Afterload reducers such as hydralazine, amlodipine, or ACE inhibitors

    Diagnosis of Hypertrophic Cardiomyopathy

    • Echocardiogram:
      • Left ventricular dilation
      • Left atrial enlargement
      • Normal to increased left ventricular wall thickness (increased with aortic stenosis)
      • Mitral regurgitation
      • Aortic regurgitation
      • Normal to increased transaortic velocities
      • Vegetative valvular lesions
      • Thickened aortic valve leaflets
    • Electrocardiogram:
      • Tall R waves in lead II suggestive of left ventricular enlargement
      • Wide P waves in lead II suggestive of left atrial enlargement
      • Ventricular arrhythmias
      • Supraventricular premature beats
      • Atrial fibrillation
    • Thoracic radiographs:
      • Normal in dogs with an early stage of the disease
      • Left atrial enlargement
      • Left ventricular enlargement
      • Enlarged pulmonary veins

    Heartworm Disease

    • Clinical Signs:
      • Cough
      • Exercise intolerance
      • Weight loss
      • Lethargy
      • Dyspnea
      • Syncope
    • Diagnostic Tests:
      • Heartworm antigen test: Detects antigen found in the uterus of female worms (ELISA tests are highly sensitive and specific)
      • Heartworm antibody test: Nonspecific and no longer used in dogs
      • Microfilaria test:
        • Microfilaria are present in 70% to 80% of dogs
        • Reasons for absence of microfilaria:
          • Testing within prepatent period
          • Low worm burden
          • All-male infection
          • Immunologic destruction by the host
          • Receiving macrolide preventative
      • Thoracic radiographs:
        • May be normal
        • Enlarged main pulmonary artery
    • Other Tests:
      • Complete blood count:
        • Anemia
        • Leukocytosis
        • Neutrophilia
        • Monocytosis
        • Lymphopenia
        • Eosinophila
        • Basophilia
        • Circulating microfilaria
        • Thrombocytopenia
      • Biochemistry panel:
        • May be normal
        • Elevated serum alanine transferase, serum alkaline phosphatase
        • Hyperglobulinemia
        • Azotemia
      • Urinalysis: Proteinuria

    Treatment of Heartworm Disease

    • Microfilariacidal:
      • Slow kill rate with preventative doses of ivermectin, milbemycin oxime, and selamectin
      • Corticosteroids, antihistamines, or both may be administered 1 hour before microfilaricide to decrease the chance for adverse effects
    • Adult heartworm treatment:
      • Melarsomine dihydrochloride:
        • Requires hospitalization and monitoring
        • Risk of adverse effects
        • Multiple injections over several weeks
        • Not suitable for all dogs, especially very young or very old patients, or those with severe heart disease
    • Preventative medications:
      • Ivermectin
      • Milbemycin oxime
      • Selamectin
      • Moxidectin
      • Heartgard (ivermectin) and Trifexis (milbemycin oxime)

    Life Cycle of Heartworm

    • L1 microfilariae are ingested by a mosquito
    • Mosquito injects L3 larvae into a dog
    • L3 larvae develop into adult worms in the heart and pulmonary arteries within 6 months
    • Adult female heartworms release microfilariae into the bloodstream
    • Microfilariae are ingested by mosquitoes
    • Cycle repeats

    Key Points of Heartworm Disease in Dogs

    • Dirofilaria immitis (heartworm) is a parasitic nematode that infects the heart and pulmonary arteries of dogs.
    • The disease is transmitted by mosquitoes.
    • Symptoms of heartworm disease can include coughing, difficulty breathing, weight loss, lethargy, and syncope.
    • The disease can be diagnosed with a heartworm antigen test, a microfilaria test, or a combination of both.
    • Treatment for heartworm disease is available but can be challenging.
    • Prevention is the best way to protect dogs against heartworm disease.

    Patent Ductus Arteriosus

    • Rarely closes spontaneously
    • Blood shunts from the aorta to the pulmonary artery
    • Common in English Springer Spaniel, English Bulldog breeds
    • Clinical signs can be normal; however, exercise intolerance, lethargy, cough, and dyspnea can occur
    • Physical examination may reveal a systolic right sternal or left basilar murmur. Loud murmurs are associated with small ventricular septal defects
    • Diagnosis can be achieved through thoracic radiographs, angiography, or esophageal endoscopy.
    • Surgical ligation of the ligamentum arteriosum is required to treat the condition
    • Prognosis is good to guarded. Residual esophageal damage can persist

    Acquired Heart Disease

    • Myocardial Disease

      • Dogs
        • Dilated cardiomyopathy
        • Arrhythmogenic right ventricular cardiomyopathy
        • Hypertrophic cardiomyopathy
      • Cats
        • Hypertrophic cardiomyopathy
        • Dilated cardiomyopathy
        • Restrictive cardiomyopathy
        • Arrhythmogenic right ventricular cardiomyopathy

    • Dilated Cardiomyopathy in Dogs

      • Heritable in some breeds including boxer, Doberman pinscher, Great Dane, and Newfoundland
      • More common in male dogs
      • Preclinical:
        • Left ventricular dilation
        • Left ventricular systolic dysfunction
        • Left atrial enlargement
        • Right atrial enlargement
        • Right ventricular enlargement
        • Enlarged pericardium and pericardial effusion
        • Enlarged pulmonary veins
        • Pulmonary edema
        • Pleural effusion

    • Diagnosis of Dilated Cardiomyopathy in Dogs

      • Echocardiogram
      • Electrocardiography
      • Thoracic radiographs
      • Plasma taurine levels
      • Thyroid panel (T4, free T4, TSH)
      • Chagas titer

    • Treatment

      • Preclinical
        • ACE inhibitor
        • Beta blockers are under investigation
      • Congestive Heart Failure (CHF)
        • Oxygen
        • Diuretics
        • ACE inhibitor
        • Pleurocentesis
        • Abdominocentesis
      • Antiarrhythmic therapy
      • Thromboembolism
        • Aspirin, clopidogrel
        • Pain medication
        • Physical therapy

    • Restrictive Cardiomyopathy in Cats

      • Classified as normal to mildly increased ventricular wall thickness with atrial enlargement.
      • Clinical signs:
        • Exercise intolerance
        • Lethargy
        • Dyspnea
        • Right- and left-sided heart failure
        • Cough
        • Dyspnea
        • Ascites
        • Syncope
        • Sudden death
        • Anorexia
        • Weight loss
      • Physical examination
        • Systolic left or right heart murmur associated with atrioventricular valvular regurgitation
        • Gallop
        • Arrhythmia
        • Normal to decreased pulse quality
        • Pulse deficits
        • Normal to pale mucous membrane color
      • Thoracic radiographs
        • Generalized cardiomegaly
        • Left and/or right atrial enlargement
        • Left ventricular enlargement
        • Enlarged pulmonary veins
        • Pulmonary edema
        • Pleural effusion
      • Laboratory Tests
        • Complete blood count (CBC):
          • Anemia
          • Lymphopenia
          • Eosinophilia
          • Basophilia
          • Circulating microfilaria
          • Thrombocytopenia
        • Biochemistry panel:
          • May be normal
          • Elevated serum alanine transferase, serum alkaline phosphatase
          • Hyperglobulinemia
          • Azotemia
        • Urinalysis
          • Proteinuria

    • Treatment

      • Microfilaricidal
        • Slow kill rate with preventative doses of ivermectin, milbemycin oxime, and selamectin
        • Corticosteroids, antihistamines, or both may be used 1 hour before microfilaricides to decrease the chance of adverse effects
      • Positive inotropic therapy
      • Taurine supplementation
      • ACE inhibitor
      • CHF
        • Oxygen
        • Diuretics
        • Pleurocentesis
        • Abdominocentesis
      • Antiarrhythmic therapy
      • Thromboembolism
        • Aspirin, clopidogrel
        • Pain medication
        • Physical therapy

    . Prognosis

    • Favorable with taurine supplementation
    • Poor if idiopathic

    Heartworm Disease in Dogs

    • Heartworm antigen test can detect antigen in the uterus of female heartworms.
    • ELISA tests are highly sensitive and specific.
    • Heartworm antibody test is nonspecific and no longer used in dogs.
    • Microfilaria tests (e.g., DiFil or modified Knott) are used to identify circulating microfilaria.
    • Thoracic radiographs can reveal enlarged main pulmonary artery.
    • Prevention of heartworm disease should start at 6-8 weeks of age, especially in endemic locations.
    • Macrolide lactones such as ivermectin, milbemycin oxime, and selamectin are used for preventing heartworm disease.
    • Macrolides have microfilaricidal properties
    • Treatment for heartworm disease involves using melarsomine, which kills adult heartworms.
    • Melarsomine can induce a hemolytic anemia in dogs
    • Melarsomine can be administered intravenously or subcutaneously
    • Surgical removal of adult heartworms may be necessary.
    • Dogs require melarsomine treatment after surgical removal of the heartworms.

    Heartworm Disease in Cats

    • Heartworm antigen test detects antigen found in the uterus of gravid female heartworms.
    • Heartworm antigen tests are not particularly sensitive for detecting heartworms in cats.
    • Microfilaria test such as the DiFil or modified Knott test is used to identify circulating microfilaria.
    • Thoracic radiographs can reveal pulmonary artery enlargement, bronchointerstitial to alveolar pulmonary pattern, generalized heart enlargement, and pleural effusion.

    Pulmonic Stenosis

    • Occurs when the pulmonic valve does not open fully, restricting blood flow from the right ventricle to the pulmonary artery.
    • Leads to right ventricular hypertrophy and reduced cardiac output.
    • Clinical signs can be mild or severe.
    • Prognosis is favorable in mild to moderate cases, but guarded to poor in severe cases.

    Treatments

    • Balloon valvuloplasty: For severe or symptomatic valvular pulmonic stenosis.
    • Surgery:
      • Resection of the stenotic area and replacement with a patch graft.
      • Conduit around stenosis, especially if aberrant coronary artery.
    • Medical management:
      • β-blocker therapy.
      • Congestive right-sided heart failure management:
        • Oxygen.
        • Diuretics.
        • ACE inhibitors.
        • Pleurocentesis.
        • Abdominocentesis.

    Diagnosis

    • Echocardiogram: Evaluates the severity of stenosis, valve morphology, and right ventricular function.
    • Electrocardiogram: Reveals right ventricular hypertrophy, right axis deviation, and tall P waves in lead II suggestive of right atrial enlargement.
    • Thoracic radiographs: Show right ventricular enlargement, decreased pulmonary vasculature, and poststenotic dilation of the main pulmonary artery.
    • Packed cell volume (PCV): Monitors for polycythemia.
    • Arterial blood gas: Monitors for hypoxemia.

    Tetralogy of Fallot

    • A congenital heart defect characterized by ventricular septal defect, pulmonic stenosis, overriding aorta, and right ventricular hypertrophy.
    • Pulmonic stenosis causes obstruction to blood flow into the pulmonary artery, leading to deoxygenated blood delivered to the systemic circulation, resulting in hypoxemia.
    • Most common cyanotic congenital heart defect in dogs.
    • May lead to polycythemia.
    • Inherited as a simple autosomal recessive trait.
    • Common breeds: Keeshond, English bulldog.

    Clinical Signs

    • May be normal in early stages.
    • Exercise intolerance.
    • Lethargy.
    • Syncope.
    • Seizures (resulting from polycythemia).
    • Dyspnea (resulting from hypoxemia).
    • Ascites.

    Physical Examination

    • Cyanosis with and without exercise.
    • Systolic left or right basilar murmur of pulmonic stenosis.
    • Normal pulse quality.
    • Highly variable depending on ventricular wall thickness, atrial enlargement, and presence of clinical signs.

    Treatments

    • Balloon valvuloplasty: For severe or symptomatic valvular pulmonic stenosis.
    • Surgery:
      • Resection of the pulmonic stenosis and replacement with a patch graft.
      • Patch graft of the ventricular septal defect.
      • Blalock Taussig shunt: Connects the left subclavian artery to the pulmonary artery to create a communication between the pulmonary and systemic circulation.
    • Medical management:
      • Phlebotomy: PCV should be maintained below 60% to 65% to reduce polycythemia.
      • Hydroxyurea: Treats polycythemia, but has side effects related to myelosuppression.
      • β-Blockers: Relieve hypoxemic episodes associated with sympathetic drive.
      • Congestive heart failure (CHF) management:
        • Oxygen.
        • Diuretics.
        • ACE inhibitors.
        • Pleurocentesis.
        • Abdominocentesis.

    Prognosis

    • Mild: Favorable, rarely develop clinical signs
    • Moderate: May develop clinical signs
    • Severe: Develop clinical signs, prognosis is poor

    Feline Hypertrophic Cardiomyopathy (HCM)

    • Increased risk in male cats.
    • Prepatent period is 8 months.
    • Most common causes in cats.

    Clinical Signs

    • Similar to hypertrophic cardiomyopathy in dogs: Weakness, lethargy, anorexia, weight loss, ascites, syncope, sudden death.

    Physical Examination

    • Muffled heart sounds.
    • Jugular venous distension.
    • Weak or varying pulse quality.
    • Arrhythmia.
    • Pulse deficits.
    • Normal to pale mucous membrane color.
    • Ascites.
    • Dyspnea.

    Diagnosis

    • Echocardiogram:
      • Normal to mild left ventricular wall thickening.
      • Diastolic ventricular dysfunction.
      • Biatrial enlargement.
      • Mitral regurgitation.
      • Pleural effusion.
      • Pericardial effusion.
    • Electrocardiogram: Similar to hypertrophic cardiomyopathy in dogs, creating a potential risk of adverse reactions.
    • Thoracic radiographs:
      • Normal in cats with an early stage of the disease.
      • Generalized cardiomegaly.
      • Pleural effusion.

    Treatment

    • Echocardiogram:
      • May be normal.
      • Right ventricular enlargement.
      • Main pulmonary artery enlargement.
      • Tricuspid regurgitation.
      • Heartworms within the right atrium, ventricle, or pulmonary artery.
      • Considered a sensitive test for detecting the presence of heartworms in cats.
    • Complete blood count (CBC):
      • May be normal.
      • Anemia.
      • Neutrophilia.
      • Lymphopenia.
      • Eosinophilia.
      • Basophilia.
      • Circulating microfilaria.
      • Thrombocytopenia.
    • Biochemistry panel:
      • May be normal.
      • Hyperglobulinemia.
      • Azotemia.
    • Urinalysis: Proteinuria.

    Treatment for Heartworm Disease

    • Microfilaricide: Microfilaria-positive cats are rarely encountered.
    • Surgery: Surgical repair in symptomatic patients.
    • Prognosis: Excellent unless adhesions complicate the surgical repair.

    Acquired Disorders

    • Constrictive pericardial disease: Fibrosis of the pericardium leads to restriction of cardiac filling and a reduction in cardiac output.
      • Idiopathic or inflammatory.
      • Difficult to diagnose.
      • Treatment consists of surgically stripping the pericardium from the myocardium, and is associated with increased morbidity and mortality.
    • Pericardial effusion: Results in impaired ventricular filling and decreased cardiac output.
      • Occurs more often in middle-aged to older large breed dogs.
      • Causes:
        • Neoplasia:
          • Hemangiosarcoma.
        • Inflammatory conditions:
          • Feline infectious peritonitis.
        • CHF.

    Clinical Signs

    • Weakness, lethargy, anorexia, weight loss, ascites, syncope, sudden death.

    Physical Examination

    • Highly suggestive of pericardial effusion:
      • Muffled heart sounds.
      • Jugular venous distension.
      • Weak or varying pulse quality.
    • Arrhythmia.
    • Pulse deficits.
    • Normal to pale mucous membrane color.
    • Ascites.
    • Dyspnea.

    Diagnosis

    • Echocardiogram: Preferably performed before pericardiocentesis if the patient is stable.
    • Pericardiocentesis:
      • Fluid analysis:
        • Transudate.
        • Modified transudate.
        • Exudate.
        • Hemorrhagic.
        • Chylous.

    Treatment

    • Surgical repair: In symptomatic patients.
      • Prognosis: Excellent unless adhesions complicate the surgical repair
      • This is a complex procedure, and is associated with high morbidity and mortality.

    Heartworm Treatment in Dogs

    • Heartgard Plus:
      • Safe for use in Collies at the preventative dose.
      • Contains ivermectin and pyrantel.
      • Ivermectin has adulticide effect after prolonged continuous monthly use.
    • Oral medications:
      • Ivermectin (Heartgard): Effective against the adult stage of heartworms.
      • Milbemycin oxime (Interceptor): Effective against L3 and L4 larvae.
    • Topical medications:
      • Selamectin (Revolution): Provides adulticidal coverage.
      • Moxidectin (Advantage Multi): Provides adulticidal coverage.
    • Diethylcarbamazine:
      • Administered daily.
      • Effective against L3 and early L4 larvae, but not effective against adults.
      • Caution: Administration to microfilaremic dogs can lead to anaphylactic reaction and death.
    • Prognosis:
      • Favorable in mild to moderate cases.
      • Guarded if severe disease with clinical signs.
      • Guarded to poor with caval syndrome.

    Cardiovascular Physiology Definitions

    • Afterload: Force on the ventricle during contraction.
    • Preload: Blood volume in ventricle at the end of diastole.
    • Chronotropy: Heart rate.
      • Positive chronotropy: Increased heart rate
      • Negative chronotropy: Decreased heart rate
    • Inotropy: Myocardial contractility.
      • Positive inotropy: Increased contractility.
      • Negative inotropy: Decreased contractility.
    • Systole: Heart chamber contraction.
    • Diastole: Period of heart chamber relaxation.

    Congestive Heart Failure

    • Backward: Blood backs up in the circulatory system.
    • Forward: Reduced cardiac output.
    • Left-sided: Pulmonary edema.
    • Right-sided: Hepatomegaly, ascites, pleural effusion, and pericardial effusion.
    • Neuroendocrine consequences:
      • Renin-angiotensin-aldosterone system (RAAS) activation: Decreased cardiac output triggers renin release, leading to angiotensin I conversion, angiotensin II production, and subsequent vascular smooth muscle constriction and increased blood volume.
      • Sympathetic nervous system activation: Increased heart rate and contractility.

    Patent Ductus Arteriosus (PDA)

    • A connection between the aorta and pulmonary artery that fails to close after birth.
    • Spontaneous closure: Rare.
    • Left to right shunt: Blood flows from the aorta to the pulmonary artery.
    • Common breeds: English Springer Spaniel, English Bulldog.
    • Clinical signs: May be normal, exercise intolerance, lethargy, cough, dyspnea.
    • Physical examination:
      • Systolic right sternal or left basilar murmur: Loud murmurs indicate smaller ventricular septal defects.
      • Diastolic left basilar murmur: Aortic regurgitation if aortic valve leaflet prolapses into the ventricular septal defect.
      • Normal pulse quality.
    • Diagnosis:
      • Echocardiogram: Left ventricular enlargement, left atrial enlargement, ventricular septal defect, aortic insufficiency.
      • Electrocardiography: Tall R waves in lead II (left ventricular enlargement), wide P waves in lead II (left atrial enlargement).
      • Thoracic radiographs: Normal in dogs with small septal defects, left atrial enlargement, left ventricular enlargement, pulmonary overcirculation, pulmonary edema.
    • Treatment:
      • Interventional catheterization: Device closes large ventricular septal defects.
      • Surgery:
        • Pulmonary artery banding.
        • Patch graft (difficult, requires special equipment, costly, not readily available).
      • Medical management:
        • Oxygen.
        • Diuretics.
        • Positive inotropic support.
        • Nitroglycerin ointment.
        • ACE inhibitor.
    • Prognosis:
      • Small defects: Favorable, rarely develop clinical signs.
      • Moderate to large defects: Develop clinical signs, shortened life span without defect closure.

    Vascular Ring Anomaly: Persistent Right Fourth Aortic Arch

    • The esophagus is surrounded by the pulmonary artery, ligamentum arteriosum, right aortic arch, heart base, and trachea.
    • Common breeds: German Shepherd, Irish Setter, Great Dane.
    • Clinical signs: Regurgitation due to esophageal obstruction.
    • Diagnosis: Thoracic radiographs, angiography, or esophageal endoscopy.
    • Treatment: Surgical ligation of the ligamentum arteriosum.
    • Prognosis: Good to guarded. Residual esophageal functional and structural damage may persist.

    Acquired Heart Disease

    Myocardial Disease

    Dogs

    • Dilated cardiomyopathy:
      • Heritable in some breeds (Boxer, Doberman Pinscher, Great Dane, Newfoundland).
      • More common in male dogs.
      • Preclinical: Left ventricular dilation, left ventricular systolic dysfunction, and ventricular arrhythmias without clinical signs.
      • Clinical: Left ventricular dilation, left ventricular systolic dysfunction, and ventricular arrhythmias with clinical signs.
      • Common breeds: Doberman Pinscher, Newfoundland, Irish Wolfhound, Great Dane, Labrador Retriever, Cocker Spaniel, Boxer, Saint Bernard, Old English Sheepdog, Dalmatian.
    • Arrhythmogenic right ventricular cardiomyopathy.
    • Hypertrophic cardiomyopathy: Rare in dogs.

    Cats

    • Hypertrophic cardiomyopathy: Most common.
    • Dilated cardiomyopathy.
    • Restrictive cardiomyopathy.
    • Arrhythmogenic right ventricular cardiomyopathy.

    Dilated Cardiomyopathy in Dogs

    • Causes:
      • Tachycardia-induced: Myocardial dysfunction from a persistently fast heart rate (> 200 beats/min). Enlargement of all four heart chambers may resolve with appropriate heart rate control.
      • Toxic: Adriamycin (doxorubicin)
        • Presents with arrhythmias and myocardial failure.
        • Dose-dependent and reversible.
        • Cardiotoxicity occurs at cumulative doses of 250 mg/m2.
      • Infectious myocarditis:
        • Toxoplasma gondii.
        • Trypanosoma cruzi:
          • Vector is the reduvid bug.
          • Forms:
            • Trypomastigote in blood.
            • Amastigote in host tissue.
          • Presentation:
            • Ventricular arrhythmias and atrioventricular block.
            • Systolic dysfunction of primarily the right ventricle.
            • Heart failure.
          • No reliable cure.
          • Treatment is symptomatic.
        • Parvovirus: Affected puppies in the 1970s and 1980s.
      • Endocrine: Hypothyroidism.
      • Nutritional: Deficiencies in taurine, L-carnitine, selenium, or vitamin E.
    • Clinical signs:
      • Dyspnea.
      • Cough.
      • Weakness.
      • Lethargy.
      • Syncope.
      • Sudden death.
      • Ascites.
      • Hepatosplenomegaly.
      • Jugular venous distension.
      • Positive hepatojugular reflex.
    • Diagnosis: Based on clinical signs, echocardiography, electrocardiology, and thoracic radiographs.
    • Treatment:
      • Antiarrhythmic therapy.
      • Nutritional supplements: Taurine, L-carnitine, fish oil, coenzyme Q10.
      • Oxygen.
      • Diuretics.
      • Positive inotropic support.
      • Nitroglycerin ointment.
      • ACE inhibitor.
      • Pleurocentesis.
      • Abdominocentesis.
    • Prognosis:
      • Tachycardia-induced: Favorable with adequate heart rate control.
      • Toxic: Favorable.
      • Infectious myocarditis: Poor.
      • Endocrine: Hypothyroidism. Favorable with thyroid supplementation.
      • Nutritional: Variable.

    Hypertrophic Cardiomyopathy in Dogs

    • Idiopathic concentric hypertrophy of the ventricle.
    • Rare.
    • Rule out secondary causes of ventricular hypertrophy:
      • Aortic stenosis.
      • Systemic hypertension.
      • Significant dehydration.
      • Infiltrative neoplasia.
    • Clinical signs: Arrhythmias and heart failure.
    • Treatment: Anti-arrhythmic medications, such as sotalol or mexiletine combined with atenolol.
    • High risk of sudden death.

    Right Ventricular Dysplasia

    • Characterized by fatty or fibrofatty infiltration of the right ventricle
    • Common Breeds: Dachshund, Miniature Poodle, Cocker Spaniel, Pomeranian, Miniature Schnauzer, Boston Terrier, Chihuahua
    • Clinical Signs: May be normal; exercise intolerance, lethargy, anorexia, weight loss, left or right heart failure (cough, dyspnea, ascites), syncope, sudden death
    • Physical Examination:
      • Systolic left apical murmur with mitral regurgitation
      • Systolic right heart murmur with tricuspid regurgitation
      • Mid-systolic click
      • Normal pulse quality
      • Arrhythmia
      • Gallop
      • Dyspnea
      • Signs of right-sided heart failure if tricuspid endocardiosis or pulmonary hypertension (ascites, positive hepatojugular reflex, jugular venous distension)
    • Diagnosis: Echocardiogram
    • Prognosis:
      • Mild: Favorable; rarely develop clinical signs
      • Moderate: May develop clinical signs
      • Severe: Develop clinical signs; shortened life span, risk of sudden death

    Atrioventricular Valvular Dysplasia

    • Malformation of the valve leaflets, chordae tendinae or papillary muscles result in regurgitation of the valve, valvular stenosis, or both
    • Occurs in both dogs and cats
    • Common Breeds:
      • Tricuspid valve dysplasia: Great Dane, German shepherd, golden retriever, Labrador retriever, Weimaraner
      • Mitral valve dysplasia: Great Dane, German shepherd, golden retriever, bull terriers, numerous cat breeds
    • Clinical Signs:
      • Tricuspid valve dysplasia:
        • May be normal
        • Exercise intolerance
        • Tetralogy of Fallot
      • Mitral valve dysplasia:
        • May be normal
        • Exercise intolerance
        • Lethargy
        • Anorexia
        • Weight loss
        • Left or right heart failure (cough, dyspnea, ascites)
        • Syncope
        • Sudden death
    • Diagnosis:
      • Tricuspid valve dysplasia:
        • Echocardiogram: Right atrial enlargement, right ventricular enlargement
        • Electrocardiography: Right axis deviation, tall P waves in lead II suggestive of right atrial enlargement, supraventricular premature beats, atrial fibrillation
        • Thoracic radiographs: Normal with mild disease, right atrial enlargement, right ventricular enlargement, caudal vena cava enlargement, pleural effusion.
      • Mitral valve dysplasia:
        • Echocardiogram: Left atrial enlargement, left ventricular enlargement
        • Thoracic radiographs: (Figure 12-5)
    • Treatment:
      • Tricuspid valve dysplasia:
        • Not typically treated, but medical management for heart failure may be necessary.
      • Mitral valve dysplasia:
        • Surgical: Patch graft of the ventricular septal defect, Blalock Taussig shunt
        • Medical: Phlebotomy (maintain PCV below 60-65%), Hydroxyurea, Beta-blockers to relieve hypoxemic episodes associated with sympathetic drive, CHF treatment (oxygen, diuretics, ACE inhibitors, pleurocentesis, abdominocentesis)

    Tetralogy of Fallot

    • Characterized by a ventricular septal defect, pulmonic stenosis, overriding aorta and right ventricular hypertrophy
    • Pulmonic stenosis creates an obstruction to blood flow into the pulmonary artery. Deoxygenated blood is delivered to the systemic circulation, resulting in hypoxemia
    • Most common cyanotic congenital heart defect in dogs
    • May result in polycythemia
    • Inherited as a simple autosomal recessive trait
    • Common Breeds: Keeshond, English Bulldog
    • Clinical Signs: May be normal; exercise intolerance, lethargy, syncope, seizures resulting from polycythemia, dyspnea resulting from hypoxemia, ascites
    • Physical Examination:
      • Cyanosis with and without exercise
      • Systolic left or right basilar murmur of pulmonic stenosis
      • Might not have an audible murmur
      • Normal pulse quality
    • Treatment:
      • Medical: Phlebotomy to maintain PCV below 60-65%, hydroxyurea, beta-blockers
      • Surgical: Patch graft of the ventricular septal defect, Blalock Taussig shunt (connects the left subclavian artery to the pulmonary artery)
    • Prognosis: Variable, dependent on severity of the defect and treatment options

    Patent Ductus Arteriosus (PDA)

    • Typically shunt left to right
    • Common Breeds: English Springer Spaniel, English Bulldog
    • Clinical Signs: May be normal; exercise intolerance, lethargy, cough, dyspnea
    • Physical Examination:
      • Systolic right sternal or left basilar murmur. Loud murmurs are associated with small ventricular septal defects.
      • Diastolic left basilar murmur associated with aortic regurgitation if aortic valve leaflet prolapses into USD
      • Normal pulse quality
    • Diagnosis: Echocardiogram (left ventricular enlargement, left atrial enlargement, ventricular septal defect, aortic insufficiency) and Electrocardiography (tall R waves in lead II suggestive of left ventricular enlargement, wide P waves in lead II suggestive of left atrial enlargement, ventricular arrhythmias, supraventricular arrhythmias)
    • Treatment: Surgical ligation of the ligamentum arteriosum
    • Prognosis: Good to guarded. Residual esophageal functional and structural damage may persist

    Myocardial Disease

    • Dogs:
      • Dilated Cardiomyopathy (DCM)
      • Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)
      • Hypertrophic Cardiomyopathy (HCM)
    • Cats:
      • Hypertrophic Cardiomyopathy (HCM)
      • Dilated Cardiomyopathy (DCM)
      • Restrictive Cardiomyopathy (RCM)
      • Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)

    Dilated Cardiomyopathy (DCM) in Dogs

    • Heritable in some breeds (Boxer, Doberman pinscher, Great Dane, Newfoundland)
    • More common in male dogs
    • Preclinical Stage: Denoted by the presence of left ventricular dilation, left ventricular systolic dysfunction, and/or decreased fractional shortening
    • Clinical Signs: Anorexia, lethargy, syncope, sudden lameness, sudden death
    • Physical Examination:
      • Systolic sternal murmur
      • Gallop
      • Arrhythmia
      • Normal to decreased pulse quality
      • Normal to pale mucous membrane color
      • Dyspnea
      • Crackles
      • Ascites
      • Hepatosplenomegaly
      • Jugular venous distension
      • Pale nail beds
      • Hypothermia
    • Diagnosis: Echocardiogram (left ventricular dilation, decreased fractional shortening, left and/or right atrial enlargement, mitral regurgitation, pleural effusion, pericardial effusion)
    • Treatment: Medical management focuses on managing heart failure symptoms (oxygen, diuretics, ACE inhibitors, aldosterone antagonists).
    • Prognosis: Variable depending on severity and response to treatment.

    Hypertrophic Cardiomyopathy (HCM) in Dogs & Cats

    • Dogs:
      • Not heritable
      • More common in older dogs
      • Most common in small breed dogs (Cavalier King Charles Spaniel, Brittany, Irish Wolfhound)
      • Clinical Signs: Similar to DCM but can also include exercise intolerance, coughing, and dyspnea. Can also be asymptomatic, leading to sudden collapse.
      • Diagnosis: Echocardiogram (global or focal left ventricular wall thickening (>6 mm), papillary muscle hypertrophy, left and right atrial enlargement, mitral regurgitation, normal to increased left ventricular outflow tract velocities, diastolic dysfunction, pleural effusion, pericardial effusion)
    • Cats:
      • Most common cardiomyopathy in cats
      • Heritable
      • Treatment: Medical management (beta-blockers, calcium channel blockers, diuretics). Surgery is rarely an option.

    Cardiac Output

    • Cardiac output is the combination of stroke volume and heart rate.
    • Stroke volume is the amount of blood ejected from the left ventricle with each beat.
    • Heart rate is the number of beats per minute.

    Systemic Vascular Resistance

    • Systemic vascular resistance is the resistance to blood flow through the systemic arterioles.

    Blood Pressure

    • Blood pressure is the combination of cardiac output and systemic vascular resistance.

    Eccentric Hypertrophy

    • Eccentric hypertrophy is a dilation of the atrial or ventricular chambers with normal to decreased wall thickness.
    • It is caused by volume overload.
    • Examples of heart diseases that result in eccentric hypertrophy Include:
      • Dilated cardiomyopathy
      • Valvular endocardiosis
      • Patent ductus arteriosus (PDA)
      • Ventricular septal defect
      • Atrial septal defect (ASD)

    Concentric Hypertrophy

    • Concentric hypertrophy is a thickening of the ventricular wall.
    • It is caused by a pressure overload.
    • Examples of heart diseases that result in concentric hypertrophy include:
      • Systemic hypertension
      • Pulmonary hypertension
      • Pulmonic stenosis
      • Aortic stenosis

    Heartworm Disease

    • Heartworm disease is caused by Dirofilaria immitis.
    • It is transmitted by mosquitoes.
    • The prepatent period is 5 to 7 months in dogs.
    • The adult heartworm life span in dogs is approximately 5 years.

    Diagnosis of Heartworm Disease

    • Clinical signs:
      • May be normal
      • Cough
      • Dyspnea
      • Exercise intolerance
      • Lethargy
      • Ascites
      • Syncope
      • Anorexia
      • Weight loss
      • Hemoptysis
      • Sudden death
    • Physical Examination:
      • Systolic left or right heart murmur associated with atrioventricular valvular regurgitation
      • Gallop
      • Arrhythmia
      • Normal to decreased pulse quality
      • Pulse deficits
      • Normal to pale mucous membrane color
      • CHF:
        • Oxygen
        • Diuretics
        • Positive inotropic support
        • Nitroglycerin ointment
        • ACE inhibitor

    Treatment of Heartworm Disease

    • Medical Management:
      • Preclinical:
        • ACE inhibitor
        • Beta-blockers
      • CHF:
        • Oxygen
    • Antiarrhythmic therapy

    Prognosis of Heartworm Disease

    • Prognosis is guarded to poor.

    Pericardial Disease

    • Pericardial disease is more common in dogs.
    • Congenital Disorders:
      • Cysts: Rare in dogs. Presenting signs are similar to pericardial effusion.
      • Peritoneopericardial diaphragmatic hernia:
        • Allows for pericardial effusion.
        • Presenting signs may include:
          • Dyspnea
          • Exercise intolerance
          • Lethargy
          • Syncope

    Pericardial Effusion: Common causes

    • Pericardial effusion is a buildup of fluid in the pericardial sac.
    • Causes include:
      • Idiopathic
      • Neoplasia
        • Lymphoma:
          • Rapid growth
          • Early metastatic rate
        • Mesothelioma:
          • Diffuse neoplasia of the pericardium, pleura, and peritoneum
          • Slow rate of growth
          • Late metastatic rate
    • Presenting Signs:
      • May be normal
      • Dyspnea
      • Lethargy
      • Exercise intolerance
      • Left- and right-sided heart failure:
        • Cough
        • Dyspnea
        • Ascites
        • Syncope
        • Sudden death
        • Anorexia
        • Weight loss
    • Physical Examination:
      • Systolic left or right heart murmur associated with atrioventricular valvular regurgitation
      • Gallop
      • Arrhythmia
      • Normal to decreased pulse quality
      • Pulse deficit
      • Normal to pale mucous membrane color
      • CHF
        • Oxygen
        • Diuretics
        • Positive inotropic support
        • Nitroglycerin ointment
        • ACE inhibitor
    • Diagnostic Tests:
      • Echocardiography: Ultrasound of the heart used to evaluate structure and function
      • Electrocardiography: Records the electrical activity of the heart for analysis of heart rate and rhythm, conduction abnormalities, and chamber enlargement patterns
      • Holter Monitor: Records an electrocardiogram over an extended period
      • Thoracic Radiographs: Used to evaluate heart size and shape, assess pulmonary and mediastinal structures, and evaluate for CHF
      • Blood pressure: Systolic, mean, and diastolic systemic arterial pressure can be measured invasively (direct) or noninvasively (indirect)
      • Cardiac catheterization and angiography: Catheters placed into peripheral vessels are used to evaluate the disease
      • Left atrial enlargement
      • Left ventricular enlargement
      • Right atrial enlargement
      • Right ventricular enlargement
      • Enlarged pulmonary veins
      • Pulmonary edema
      • Pleural effusion
      • Plasma taurine levels
      • Thyroid panel (thyroxine [T4], free T4 by equilibrium dialysis [ED], thyroid-stimulating hormone [TSH])
      • Chagas titer
    • Treatment:
      • Medical Management
        • Pericardial effusion is often treated medically.
        • Treatment includes:
          • Diuretics to reduce fluid buildup
          • Antibiotics to treat any underlying infection
          • Medications to improve heart function
          • Pericardial window: A surgical procedure to relieve pressure on the heart.

    Acanthocheilonema Reconditum

    • Acanthocheilonema reconditum (formerly Dipetalonema reconditum)
    • Acanthocheilonema reconditum is a type of roundworm that infects dogs.
    • The life span of an adult heartworm is less than 4 years.
    • The heartworm burden is typically lower, in the range of one to nine worms.
    • Clinical signs:
      • May be normal
      • Lethargy
      • Vomiting
      • Cough
      • Dyspnea
      • Anorexia
      • Syncope
      • Sudden death
    • Physical examination:
      • May be normal
      • Murmur
      • Arrhythmia
      • Gallop rhythm
      • Abnormal bronchovesicular sounds
      • Dyspnea
      • Ascites
      • Jugular venous distension

    Diagnosis of Acanthocheilonema reconditum

    • Heartworm antibody test: Indicates prior or current heartworm infection
    • Modified Knott's test: Allows for differentiation between Dirofilaria immitis microfilaria and Acanthocheilonema reconditum microfilaria

    Treatment of Acanthocheilonema reconditum

    • There is no specific treatment for Acanthocheilonema reconditum.
    • Treatment focuses on managing clinical signs and preventing further infection.
    • Clinical signs are treated with:
      • Corticosteroids
      • Bronchodilators
      • Oxygen
    • Prevention:
      • Preventative dose of ivermectin or milbemycine oxime
      • Adulticide:
        • Melarsomine: Not recommended due to association with important and life-threatening adverse effects
        • Medical management: Treat clinical signs with corticosteroids, bronchodilators, and oxygen as needed
        • Caval Syndrome: Surgical removal of heartworms

    Prognosis of Acanthocheilonema reconditum

    • Prognosis is favorable to guarded.
    • Preventative medication is recommended to help minimize the risk of developing Acanthocheilonema reconditum infection.

    Monthly Prevention of Heartworm Disease

    • Oral Examples:
      • Ivermectin (Heartgard)
      • Milbemycine oxime (Interceptor)
    • Topical Examples:
      • Selamectin (Revolution)
      • Moxidectin (Advantage Multi)

    Canine Heartworm Disease Treatment Options

    • Melarsomine:
      • Typically consists of a single IM injection followed in 4 to 6 weeks by two IM injections 24 hours apart
      • Seroconversion to a negative antigen test reaches approximately 90%
      • Recommended for dogs with clinical signs and abnormal diagnostics tests
      • Associated with fewer adverse effects
      • Requires added expense and a longer period of cage confinement
      • Adverse effects typically occur 5 to 7 days after melarsomine injection
    • Ivermectin
      • Kills adult heartworms after approximately 31 months of consecutive monthly administration
      • Not recommended routinely as adulticide therapy because of ongoing pulmonary and myocardial damage and potential development of caval syndrome
      • May be selected in dogs with concurrent renal or hepatic disease
    • Surgery:
      • The physical removal of heartworms is recommended with caval syndrome when the heartworms are present within the right atrium.
    • Caval Syndrome:
      • Is a potentially life-threatening condition in dogs with heartworm disease, caused by the presence of adult heartworms in the right ventricle and pulmonary arteries.
      • Signs may include:
        • Enlarged and tortuous caudal vena cava
        • Cough
        • Dyspnea
        • Ascites
        • Pleural effusion
        • Syncope
        • Sudden Death
    • Treatment of Caval Syndrome:
      • Surgery
        • Physical removal of heartworms is typically recommended.
        • Melarsomine adulticide therapy may be used concurrently with surgery.
      • Medical management
        • May include corticosteroids, bronchodilators, and oxygen to treat clinical signs.
        • Prognosis is guarded due to complex nature of the condition.

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    Test your knowledge of canine heart conditions with this quiz focused on clinical signs, diagnostic methods, and symptoms associated with heart failure in dogs. Explore the specific breed-related issues and important indicators in veterinary cardiology.

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