Diseases of the cardiovascular system III Flashcards
What is a cardiomyopathy?
Disease of the myocardium
What is a dilated cardiomyopathy?
- Common in dogs
- Characterised by ventricular dilation and thin hypomotile ventricular wall
What is hypertrophic cardiomyopathy?
- Common in cats
- characterised by hypertrophy of the ventricular wall and a restricted ventricular lumen
What is restrictive cardiomyopathy?
Characterised by a stiff ventrciular wall and marked dilation of the atrium feeding the ventricle
What is arrhythmogenic right ventricular cardiomyopathy?
- Boxers
- Fibrofatty infiltrate that preferentially affects the right ventricle
What diseases may be able to mimic a dilated cardiomyopathy?
- Taurine deficiency in cats
- L-carnitine deficiency in boxers
- Toxins
- Grain-free diets
- Lamb based diets
What breeds are predisposed to dilated cardiomyopathy?
- Medium to large breed dogs, e.g dobermans, great danes…
- Doberman pinschers are autosomal dominant (splice-site mutation)
- Great danes- appears to be familial, male dogs are over-represented suggesting X-linked inheritance
What is the clinical presentation of dilated cardiomyopathy?
Adult onset disease
* asympomatic/ occult phase = usually progressive
* Symptomatic phase = coughing, dyspnoea, ascites
What are the common physical findings of the occult phase of dilated cardiomyopathy?
- soft sytolic heart murmur
- Irregular heart rhythm
- Pulse deficits
What are the occasional clinical signs of the occult phase of dilated cardiomyopathy?
- Diastolic gallop
- Weak pulse
- Jugular vein distension
- Decreased intensity of heart sounds
What are the overt clinical signs of dilated cardiomyopathy?
- Moderate intensity
- Irregular heart rhythm
- Pulse deficits
- Tachypnoea
- Dyspnoea
- Weakness
- Increased bronchovesicular sounds
What are the less common clinical signs of dilated cardiomyopathy?
- Jugular vein distension
- Ascites
- Hepatomegaly
- Pale MM, hypothermia
What is the only reliable way to diagnose DCM?
Echocardiography
What echocardiography is recommended for adult dogs of at risk breeds (for DCM) ?
Annual two dimensional and M-Mode echocardiography
-ECG for signs of LV and LA enlargement
What are the cardiac biomarkers for dilated cardiomyopathy?
Troponin
What is hypertrophic cardiomyopathy?
primary myocardial disease that results in thickening of the left ventricular walls
What is the prevalence of HCM in the feline population?
Up to 20% in the general feline population
What is the relationship between Hypertrophic cardiomyopathy and Maine Coons?
- Causative mutation in A31P in the cardiac myosin Binding Protein C sarcomeric gene for inherited HCM, with autosomal domiannt inheritance
What is the relationship between hypertrophic cardiomyopathy and ragdoll cats?
- Substitution mutation in MYBPC3 associated with HCM was associated in 2007
What are the clinical signs of HCM in cats?
- Often asymptomatic- murmur or gallop is picked up at routinee examination
- Heart murmurs can be absent in cats with HCM and heart failure
- Best heard over the left apex or cranial sternum- often dynamic
What are the cliniical signs of congestive heart failure?
- Anorexia, Lethargy, Dyspnoea, Syncope, Pleural effusion/ pulmonary oedema
- Feline aortic thromboembolism
How might you diagnose Congestive Heart Disease?
Evaluate and test for diseases that cause secondary hypertrophy
* Important to do so before making a diagnosis
What is the phenotype for echocardiography for felien HCM?
- Papillary muscle hypertrophy
- Increased LV wall thickness
- Systolic anterior motion of the mitral valve
- Left atrial enlargement
- Spontaneous echo contrast
What does a spontaneous echo contrast look like?
‘smoke sign’