AHT 1210 Module E Review PDF

AHT 1210 Module E Review Module E1 Cardiomyopathy Heart Disease - Any clinical finding in the cardiac system that falls outside normal limits - Abnormal findings include: a murmur, abnormal electrocardiogram or abnormal US - Heart disease does not necessarily imply heart failure but many...

AHT 1210 Module E Review Module E1 Cardiomyopathy Heart Disease - Any clinical finding in the cardiac system that falls outside normal limits - Abnormal findings include: a murmur, abnormal electrocardiogram or abnormal US - Heart disease does not necessarily imply heart failure but many animals with heart disease will eventually develop heart failure Heart Failure - An inability of the heart to deliver enough blood to the tissues to meet the metabolic demands of the tissues - This occurs when the compensatory mechanisms of the cardiovascular system overwhelm the heart disease - In mild forms of heart failure, the CO falls and arterial blood pressure increases in response to physical exertion but no clinical signs are detectable - As heart failure worsens, clinical signs become detectable at lower levels of exertion and eventually at rest - The end state of heart failure is CHF Congestive Heart Failure - The volume of blood delivered to the heart is more than the hearts capacity to move it along: therefore fluid builds up “behind” the heart producing congestion in the affected organ - If the left ventricle is failing, then the congestion occurs in the lungs, resulting in pulmonary edema - If the right ventricle is failing then the congestion occurs in the liver, resulting in ascites - Animals can have both LV and RV failure Classification of Heart Disease and Heart Failure Class A Patient at high risk for developing heart disease, but currently has no identifiable structural disorder of the heart (Cavaliers, Dobermans) Class B Patient has structural heart disease but has never had clinical signs of heart failure (may have a murmur) B1: asymptomatic patient, no radiographic or US evidence of heart enlargement B2: asymptomatic patient with radiographic or US evidence of heart enlargement Class C Patient with past or current clinical signs of heart failure associated with structural heart disease Class D Patients with end stage heart failure exhibiting clinical signs that are refractory to standard therapy Pathogenesis of Heart Disease Disease Characteristics Clinical Signs Diagnosis Treatments Dilated Can occur in cats fed taurine Sudden Death: common due to History and C/S Stage A: no therapies Cardiomyopathy deficient diets the acute onset of lethal arrhythmia, cough, soft cough CBC/Chem/UA - assess Stage B: delaying onset of CHF DCM accounts for 5-10% of PCV, renal function - Ace inhibitors such as all canine cardiac disease: Exercise intolerance, weakness, enalapril or benazepril - Inherited defect in lethargy: decreasing exercise Imaging - thoracic - Check renal function the myocardium ability and increasing lethargy radiographs (evidence of - If patient has ventricular - Dobermans, Boxers, as their disease progresses pulmonary edema and arrhythmias then start sotalol Great Danes, GSD, changes in heart size and - Pimobendan to prolong onset Newfies, Labs, Irish Anorexia, muscle wasting and shape) of CHF Wolf Hounds weight loss: cachexia and enter Cardiac US (heart function, Stage C: furosemide to reduce edema catabolic state confirm diagnosis) - Ace inhibitors - Pimobendan as standard Syncope (fainting): decreased Other tests: therapy, has both ionotropic cerebral perfusion can be due to abdominal/thoracentesis - and vasodilating properties arrhythmias, decreased CO or type of fluid indicates source Stage D: end stage challenging to both manage ECG - rhythm and chamber - Increase furosemide and Abdominal Distension: ascites size additional diuretics, sodium may be present restriction and increase ace inhibitor Pale MM, prolonged CRT and weak pulses Hypertrophic Most common in cats Asymptomatic PE - heart murmur Goal is to decrease the heart rate to Cardiomyopathy allow time for the left ventricle to fill Abnormal thickening of the Sudden death: may preceded CBC/Chem/UA/BP: systemic - Atenolol: used in cats with left ventricle which results in by stressful event hypertension and hypertension or in cats with small lumen of the left hyperthyroidism can lead to HCM that do not have signs ventricle Resp distress: dyspnea and this of CHF tachypnea, coughing is rarely - Diltiazem: will lower heart Genetic basis - Maine Coon noted, resp signs due to US: gold standard rate and is used in cats with and Ragdoll cats pulmonary edema and pleural HCM once signs of CHF are effusion Cardiac Biomarkers - controlled  proBNP - used to CHF Exercise intolerance: difficult to differentiate cats that are in - Ace inhibitor assess but less active and CHF - Furosemide: not licensed for playing less cats but currently being investigated in some cats Syncope with CHF - Clopidogrel or aspirin Thromboembolic Disease therapy: used for antithrombotic therapy Module E2 Chronic Valvular Heart Disease Characteristics: - Accounts for 75-80% of all canine cardiac disease - Exact cause is unknown - Most common cause is endocardiosis, an abnormal thickening of the heart valves, especially the mitral valve - Occurs most commonly in small, middle to older aged males, can occur in females and also occasionally seen in large breed dogs - Cavalier king charles spaniels are particularly predisposed to developing CVHD Clinical Signs - Cough: - The most common clinical sign is a cough that initially occurs with exercise, then as the disease progresses, eventually occurs even at rest, especially at night - The cough is caused by tracheal elevation and compression of the enlarged heart and/or presence of pulmonary edema - Exercise Intolerance: - As heart function declines, the animal is increasingly unable to tolerate physical activity, exercise produces coughing - The animal also displays lethargy and weakness due to poor muscle perfusion - Tachypnea and Dyspnea - As pulmonary edema occurs and advances, dyspnea and tachypnea occur - If RV failure also occurring, the resulting thoracic compression can also contribute to tachypnea and dyspnea - Syncope  - In advanced heart failure syncope may occur due to decreased cerebral perfusion Diagnosis of Valvular Disease - Stage A - Dogs that are known to have predisposition to CVHD such as the cavalier king charles spaniel, should have a regular evaluation - Stage B, C, D - Thoracic radiographs - Blood pressure measurements - US to look for the cause of the murmur and to evaluate chamber size - Bloodwrok, evaluate kidney parameters, Hct, TP and UA as a minimum data base Treatment of Valvular Disease - Stage A and B1 - No drug or dietary therapy is recommended - Re evaluation with ultrasound in 12 months - Stage B2 - Ace inhibitors - Dietary therapy - Mild sodium restrictions - Palatable diet with adequate protein levels - Stage C - Furosemide - Ace inhibitor - Pimobendan - Hospital based therapy may include - Oxygen therapy - Nitroprusside for pulmonary edema - Dietary therapy - Adequate calorie intake to minimize weight loss - Adequate protein intake - avoid low protein diets - Moderate sodium restrictions - Monitor potassium levels and supplement diet with potassium if hypokalemia is identified  - Stage D - Continue use of furosemide, ace inhibitors and pimobendan - Oxygen supplementation if required - Thoracentesis may be necessary to relieve respiratory distress - Nitroprusside or amlodipine for vasodilation - Dietary therapy - Same as stage C, if fluid is accumulating then further sodium restrictions are in order Module E3 Characteristics of Heartworm Heartworm (Dirofilaria immitis) - Heartworm definitive hosts are dogs, cats and ferrets - Zoonotic potential - humans are not a suitable host - Occurs in climates where summer temperatures are high enough for the larvae to survive in the mosquito - Occur in ontario, manitoba, quebec, okanagan valley Life Cycle - Indirect - Transmitted by mosquitoes (intermediate host) - Adults reside primarily in the pulmonary arteries and right ventricle - Adults produce offspring called microfilaria which are released into the bloodstream - In an infected dog, microfilariae will continuously circulate until taken up by a mosquito - Infective larvae enter the next dog through the skin puncture wound - Immature adults enter the venous circulation and travel to the heart - 3 months of maturation are required for the immature adults to mature and for females to start producing microfilariae - Prepatient period is 6-6 ½ months Clinical Signs - Fatigue and exercise intolerance - Weight loss - Respiratory impairment and coughing Diagnosis - Clinical signs and history - where they live, if they have been travelling - Initial detection of an infection relies on detecting either the antigen shed from adult worms in the serum or plasma, ELISA or the presence of microfilaria in the bloodstream Treatment - Adulticides kill adult worms present in heart and blood vessels - Microfilardicides eradicate circulating - Retest dogs after 6 months Prevention - Tested for heartworm before being placed on a preventative 1. Ivermectin 2. Milbemycin oxime 3. Selamectin 4. Moxidectino