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Questions and Answers
What is a common physical exam finding in a patient with aortic regurgitation?
What is a common physical exam finding in a patient with aortic regurgitation?
Which pathophysiological change is a direct consequence of aortic regurgitation?
Which pathophysiological change is a direct consequence of aortic regurgitation?
Which of the following is NOT a potential clinical outcome of untreated aortic regurgitation?
Which of the following is NOT a potential clinical outcome of untreated aortic regurgitation?
What is a common echocardiographic finding in a patient with aortic regurgitation?
What is a common echocardiographic finding in a patient with aortic regurgitation?
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What mechanism contributes to increased pulmonary venous pressure in left-sided heart failure secondary to aortic regurgitation?
What mechanism contributes to increased pulmonary venous pressure in left-sided heart failure secondary to aortic regurgitation?
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Which breed of dogs is most commonly affected by acquired valvular heart disease?
Which breed of dogs is most commonly affected by acquired valvular heart disease?
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What is a recognized risk factor for developing acquired valvular heart disease in dogs?
What is a recognized risk factor for developing acquired valvular heart disease in dogs?
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Which feature is characteristic of myxomatous valve disease?
Which feature is characteristic of myxomatous valve disease?
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What physical examination finding is expected in dogs with congestive heart failure secondary to acquired valvular disease?
What physical examination finding is expected in dogs with congestive heart failure secondary to acquired valvular disease?
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What structural change occurs in the aortic valve due to degeneration?
What structural change occurs in the aortic valve due to degeneration?
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Which diagnostic test is frequently used to evaluate acquired valvular heart disease?
Which diagnostic test is frequently used to evaluate acquired valvular heart disease?
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In acquired valvular heart disease, what pathophysiological condition is commonly associated with aortic regurgitation?
In acquired valvular heart disease, what pathophysiological condition is commonly associated with aortic regurgitation?
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Which layer of a normal valve is primarily composed of tightly packed collagen fibers?
Which layer of a normal valve is primarily composed of tightly packed collagen fibers?
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What is the primary structural change that occurs in the aortic valve during myxomatous degeneration?
What is the primary structural change that occurs in the aortic valve during myxomatous degeneration?
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Which of the following is a direct consequence of aortic regurgitation in dogs?
Which of the following is a direct consequence of aortic regurgitation in dogs?
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What is the primary function of the spongiosa layer in a normal aortic valve?
What is the primary function of the spongiosa layer in a normal aortic valve?
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Which of the following is a recognized risk factor for the development of acquired valvular heart disease in dogs?
Which of the following is a recognized risk factor for the development of acquired valvular heart disease in dogs?
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What is a key characteristic of myxomatous valve disease, as opposed to other types of valve disease?
What is a key characteristic of myxomatous valve disease, as opposed to other types of valve disease?
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Which pathophysiological process is directly involved in the development of myxomatous valve disease?
Which pathophysiological process is directly involved in the development of myxomatous valve disease?
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What is the term used to describe the condition where blood leaks back into the left ventricle during systole?
What is the term used to describe the condition where blood leaks back into the left ventricle during systole?
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Which of the following diagnostic tools is most commonly used to evaluate acquired valvular heart disease in dogs?
Which of the following diagnostic tools is most commonly used to evaluate acquired valvular heart disease in dogs?
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Which of the following clinical signs is commonly observed in dogs with congestive heart failure secondary to acquired valvular heart disease?
Which of the following clinical signs is commonly observed in dogs with congestive heart failure secondary to acquired valvular heart disease?
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What is the role of the fibrosa layer in a normal aortic valve?
What is the role of the fibrosa layer in a normal aortic valve?
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Which of the following results from left ventricular (LV) volume overload in aortic regurgitation?
Which of the following results from left ventricular (LV) volume overload in aortic regurgitation?
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What physiological change can cause an increase in left atrial (LA) pressure secondary to aortic regurgitation?
What physiological change can cause an increase in left atrial (LA) pressure secondary to aortic regurgitation?
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Which feature is characteristic of the murmur associated with aortic regurgitation?
Which feature is characteristic of the murmur associated with aortic regurgitation?
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Which clinical outcome is most likely to occur as a progression of untreated aortic regurgitation?
Which clinical outcome is most likely to occur as a progression of untreated aortic regurgitation?
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What change is commonly seen on an echocardiogram in a patient with significant aortic regurgitation?
What change is commonly seen on an echocardiogram in a patient with significant aortic regurgitation?
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Which of the following best describes the timing of the murmur associated with aortic regurgitation?
Which of the following best describes the timing of the murmur associated with aortic regurgitation?
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Which sign may indicate increased severity of aortic regurgitation?
Which sign may indicate increased severity of aortic regurgitation?
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What is a commonly assessed cardiac condition associated with the rise in LA and LV pressure due to aortic regurgitation?
What is a commonly assessed cardiac condition associated with the rise in LA and LV pressure due to aortic regurgitation?
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Which of the following best represents the patient's potential symptoms in advanced aortic regurgitation?
Which of the following best represents the patient's potential symptoms in advanced aortic regurgitation?
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What is a recognized arrhythmia that may be evaluated with an electrocardiogram in patients with aortic regurgitation?
What is a recognized arrhythmia that may be evaluated with an electrocardiogram in patients with aortic regurgitation?
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Study Notes
Acquired Valvular Heart Disease
- Acquired valvular heart disease is a common condition in various animal species, including dogs and horses.
- Mitral valve disease is frequently affected by acquired valvular issues. Aortic valve issues are also common in horses.
- In dogs, the condition progresses with age, and prevalence is higher in males (1.5x).
- Cavalier King Charles Spaniels are at a higher risk, along with Dachshunds, Cocker Spaniels, beagles, and various terrier breeds.
- Approximately 30% of dogs with myxomatous mitral valve disease (MMVD) will develop congestive heart failure (CHF).
- Acquired valvular disease is not restricted to canine species; it also affects horses.
Learning Objectives
- Understanding the valves affected by this disease in various species (dogs, horses, and others).
- Knowing the pathophysiology of acquired valvular disease and how it leads to heart failure in different species.
- Proficiency in appropriate diagnostic procedures to detect the disease in dogs and horses.
- Comprehending the different stages of ACVIM Classification for valvular disease in dogs and the appropriate treatment at each stage.
- Recognizing the clinical signs and physical examination findings in cases of acquired valvular heart disease, with or without congestive heart failure (CHF), in various species.
- Understanding the treatment therapies for CHF secondary to acquired valvular disease in animals.
Outline
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Definition of acquired valvular heart disease, including the various types of valve diseases (mitral, aortic).
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Clinical features of acquired valvular heart disease, including symptoms, physical exam findings (murmurs, palpation), and progression in different species.
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Pathophysiology of acquired valvular heart disease, including the disease process leading to heart failure, volume overload, and its effect on the cardiovascular system in different species.
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Physical examination findings (murmurs) of acquired valvular heart disease, specific to dogs and horses.
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Diagnostics for acquired valvular disease, including
- Echocardiography (finding thickened/irregular valve leaflets, assessing for regurgitation (MR), LA and LV enlargement)
- Thoracic radiographs (evaluating cardiac silhouette, vertebral heart score (VHS), looking for cardiomegaly in lateral and DV/VD views)
- Electrocardiography (ECG) (assessing for arrhythmias)
- Other diagnostics (blood work, blood pressure, NT-proBNP)
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Management/Staging of the disease (following ACVIM classification scheme)
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Understanding the etiology of the disease in various species (Myxomatous valvular heart disease, Degenerative valvular heart disease, Endocardiosis).
- Etiology, presentation, and clinical courses for the different species.
Normal Valve Structure
- Atrialis: Composed of elastic and collagen fibers
- Spongiosa: Contains an extracellular matrix (ECM) rich in proteoglycans and occasional interstitial cells
- Fibrosa: Tightly packed collagen fibers
Myxomatous Valve
- Non-inflammatory, progressive disarray of valve structure
- Interstitial cells become active
- Excessive deposition of the extracellular matrix (ECM)
- Fragmentation of collagen and elastic fibers
- Damage to the endothelial cell lining, leading to valvular dysfunction.
Dogs (Clinical Features)
- Acquired valvular disease is a frequent cause of heart disease in dogs (>70%) across various breeds.
- Small and medium breeds (<20 kg) are more susceptible.
- Prevalence and severity increase with age.
- More common in male dogs than in female dogs.
Valve Involvement
- Mitral valve alone is a common cause, with or without affecting the tricuspid valve.
- The majority of dogs have mitral valve alone or combined with tricuspid; aortic/pulmonary valves are less frequently affected. In horses, Aortic issues are the most frequently detected.
Normal Mitral Valve
- Separates the left atrium (LA) and left ventricle (LV), functioning as a one-way valve.
- Open during diastole and closed during systole.
- The structure includes:
- Annulus
- Leaflets
- Chordae tendineae
- Papillary muscles
- Valve leaflets should be thin, translucent, and smooth
Myxomatous Mitral Valve
- The mitral valve structure is disrupted with thickened, nodular leaflets.
- Chordae tendinae are thickened.
- The valve may prolapse or become flail, potentially leading to chordal rupture.
Pathophysiology (Myxomatous Degeneration & Mitral Regurgitation)
- Myxomatous degeneration of mitral valve tissue affects its normal function leading to abnormal motion, and potentially mitral regurgitation.
- Abnormal valve motion leads to mitral regurgitation.
- This abnormal blood flow causes volume overload, increasing LA size (enlargement), and triggering eccentric hypertrophy of the left ventricle (LV).
Pathophysiology (Chronic Decompensated MR)
- Chronic mitral regurgitation (MR) leads to decompensation with increased pulmonary pressure and congestion.
- Right ventricular (RV) function declines, with a subsequent reduction in forward stroke volume.
- Left sided heart failure can potentially arise
- Pulmonary hypertension can also ensue due to these changes.
Physical Exam - Murmur
- Murmur intensity typically increases with disease progression in both dogs and horses.
- PMI is usually localized to the cardiac apex on the left side in dogs. In horses, the murmurs are found at the cardiac base, left of the aorta.
- Murmurs may vary depending on the affected valve, whether they are systolic or diastolic, and their characteristics.
Clinical Signs
- Mild cases may be asymptomatic, but cases often show reduced exercise capacity, colic-like signs, heart rhythm disturbances, and congestive heart failure (CHF), potential leading to sudden cardiac death, in both dogs and horses.
Diagnostics
- Echocardiogram for accurate diagnosis, including evaluation of valve structure, function, and chamber sizes.
- Thoracic radiographs to assess cardiac size and identify possible cardiomegaly in both lateral and DV/VD views.
- Electrocardiogram (ECG) to evaluate for arrhythmias;
- Evaluating for systemic blood pressure & blood work (including NT-proBNP).
Echocardiogram
- Definitive diagnostic in various species, via echocardiogram.
- Shows thickened and irregular leaflets, assessing for regurgitation, and chamber sizes (particularly LA and LV).
- Demonstrates aortic/mitral regurgitations and valve thickening in the different species.
Thoracic Radiographs
- Evaluating cardiac silhouette size, vertebral heart score (VHS).
- Monitoring for progressive disease.
- Assessing the presence of cardiomegaly and distinguish between possible cardiac and respiratory causes of clinical signs
Mitral and Aortic Valve Diseases: Dogs
- Presenting ACVIM classification scheme (asymptomatic, B1, B2, C, D, stages) for staging severity of the disease in dogs.
- Details on clinical features and diagnostic procedures (echocardiogram, ECG, and radiographic findings) are relevant for dogs as well as horses.
ACVIM Classification
- Classifying cases into asymptomatic and symptomatic types (B1, B2, C, D) based on severity.
MMVD with CHF
- Cardiomegaly characterized by left atrial and ventricular enlargement.
- Interstitial to alveolar patterns (typical distribution).
- Pulmonary venous distension.
Electrocardiography (ECG)
- ECG may show normal variations or arrhythmias.
- Secondary to cardiac stretches.
- Examples include atrial, premature complexes, tachycardia, and fibrillation.
Other Diagnoses
- Blood pressure monitoring (not typically elevated in MMVD)
- NTproBNP - Cardiac biomarker, helpful for detecting progressive valve disease and for determining the cause of clinical signs.
- Comprehensive bloodwork (CBC, chemistry, urinalysis (UA), recommended before initiating therapy.
- 24-hour Holter monitors, event recorders – detect arrhythmias outside the hospital.
Other Species
- Acquired valvular disease can affect various species, including cows, parrots, and other animals, with unique considerations relevant for each species.
Horses
- Acquired valvular disease is common in adult horses (>10 years of age), usually male horses.
- Aortic insufficiency is the typical presentation resulting in a diastolic murmur.
- Diagnostic tests (Echocardiography, ECG, 24-hour Holter monitoring, bloodwork) are all important to confirm the diagnosis.
- Clinical outcomes range from asymptomatic cases to severe diseases.
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Description
Explore the essential aspects of acquired valvular heart disease, focusing on its prevalence, particularly in canine species. This quiz covers the affected valves, diagnostic techniques, and the disease's progression and implications in various animal species, including dogs and horses.
