Acquired murmurs in cats Flashcards
Two main causes of acquired murmurs in cats
Cardiomyopathies-Common
Endocardial disease- Rare
List cardiomyopathy phenotypes in cats (State the most common)
Hypertrophic cardiomyopathy (HCM) – Most Common
Restrictive cardiomyopathy (RCM)
Dilated cardiomyopathy (DCM)
Arrhythmogenic (right) ventricular cardiomyopathy (ARVC)
Non-specific cardiomyopathy (NS-CM)
End-stage Hypertrophic Cardiomyopathy
Cause of Hypertrophic cardiomyopathy phenotype in cats
Hypertension
Hyperthyroidism
Acromegaly (usually detected as diabetes mellitus)
Infiltrative diseases (e.g. lymphoma)
Transient left ventricular wall thickening
Cause of Dilated Cardiomyopathy Phenotype in cats
Dietary taurine deficiency (a risk with “alternative” diets)
Chronic tachycardia (arrhythmias)
Myocarditis
What is Hypertrophic Cardiomyopathy
Hypertrophic cardiomyopathy is when heart muscle thicken (hypertrophy.) This hypertrophied wall can obstruct blood flow, which is called obstructive hypertrophic cardiomyopathy. If blood flow is not restricted, this is called nonobstructive hypertrophic cardiomyopathy.
What is Dilated Cardiomyopathy
Dilated, poorly-contracting left ventricle
Myocarditis
Inflammation of heart muscle
Hypertrophic Cardiomyopathy- Cat breeds/sex that are predisposed to it
seen most commonly in domestic shorthairs (DSH/moggies)
British Shorthair, Bengal, Sphynx, Birman, Norwegian Forest cat, Himalayan
In male cats the disease occurs at an earlier age and is more severe
Pure bred cats are more likely to present with a severe form at a young age
Pathophysiology of HCM
- Concentric hypertrophy of left ventricle
- Poor relaxation
- Diastolic failure
- Left atrial enlargement
- Congestive heart failure/Thrombus distal aorta
What is Restrictive Cardiomyopathy
Impaired diastolic filling consequent to fibrosis of the left ventricle
T/F Specific cat breeds are predisposed to have Dilated Cardiomyopathy
False!
What are some clinical findings that suggest a cardiomyopathy
Murmur
Arrhythmia; bradycardia or tachycardia
“Gallop sounds” (i.e. audible S3/S4)
Dyspnoea
Lung crackles (pulmonary oedema)
Dullness on percussion of chest – pleural effusion
Hypothermia
Lameness/pain
Goitre if hyperthyroid
Retinal changes if hypertensive
Retinal changes if taurine deficient
What are some findings from a Thoracic Radiograph that suggest a cardiomyopathy
Cardiac silhouette enlarged
Atrial dilation
Vascular congestion
Pulmonary oedema
+/- pleural effusion
What are some blood test investigations used to diagnose cardiomyopathy
Renal function – chronic renal disease causes systemic arterial hypertension
Thyroid function
Taurine levels
Biomarkers e.g. NT-proBNP, troponin I (severity/prognostic)
Genetic tests
Significance of biomarkers (NT-proBNP and cTNI)
Can differentiate cardiac and respiratory disease in cats with dyspnoea
Cannot differentiate types of myocardial disease
Elevated levels of NT-proBNP are often indicative of heart disease, specifically CHF.
Troponin I: Elevated troponin I levels can suggest myocardial damage.
