Acquired murmurs in cats

Question 1

What are the 2 causes of acquired heart murmurs?

Answer 1

1. Myocardial disease (HCM, DCM, RCM, ARV CM, unclassified)

2. Endocardial disease (endocarditis, endocardiosis)

Question 2

What are the main causes of secondary cardiomyopathies?

Answer 2

HCM = hypertension, hyperthyroidism
DCM = taurine deficiency

Question 3

Describe the signalment for primary HCM

Answer 3

• inherited in some breeds
• males disease occurs at an earlier age and is more severe
• phenotype is v variable

Question 4

Describe the pathophysiology of primary HCM

Answer 4

1. concentric hypertrophy of LV
2. poor relaxation of myocardium
3. diastolic failure
4. LA enlargement = L CHF, thrombus in distal aorta and HQ paresis

Question 5

Describe primary RCM

Answer 5

• impaired diastolic filling in consequence to fibrosis of the LV
• definitive dx based on histopath
• no hypertophy but dilated atria and still heart walls
• can get thrombus formation in LA (can move to cd aorta, coronary arteries and kidneys)

Question 6

Describe primary DCM

Answer 6

• low prevalence

- some cases may be endstage HCM or RCM

Question 7

Describe ARVC

Answer 7

• RA and RV enlargement
• variety of arrhythmias (VT, atrial fib, SVT)
• normal thickness and diameter of LV
• normal L side systolic function
• on PM get atrophy in RV wall

Question 8

How are cardiomyopathies investigated?

Answer 8

Hx, clinical findings, diagnostic imaging, ECG

Question 9

What clinical findings are associated with CM?

Answer 9

Mumur, arrhythmia (brady/tachy), gallop rhythm, dyspnoea, lung crackles, dullness of chest percussion, hyperthyroid, hypertensive (retinal changes), taurine deficiency (retinal changes)

Question 10

What can causes murmurs in CM?

Answer 10

• L outflow tract obstruction
• R outflow tract obstruction
• mitral valve insufficiency
• tricuspid valve insufficiency

Question 11

What radiographic findings would be associated with CM?

Answer 11

• enlarged cardiac silhouette
• atrial dilation
• vascular congestion
• pulmonary oedema
• +/- pleural effusion
• elongated heart (RCM, HCM)

Question 12

What changes associated with CM would be seen on echocardiography?

Answer 12

• evaluates LV diameter (30% fractional shortening)
• subjective dilation of RV
• DCM = poor systolic function, dilated LV +/- RV, normal/reduced wall thickness
• RCM = normal systolic function, normal LV diameter, normal wall thickness, severe atrial dilation