Myocardial Disease

Question 1

Examples of myocardial disease (2)

Answer 1

1. Myocarditis - inflammation of the myocardium - resulting in resolution & fibrosis
2. Cardiomyopathy - heart disease resulting from abnormality in the myocardium

Question 2

Causes of myocarditis (3)

Answer 2

1. Infections - viral, chlamydial, rickettsial, bacterial, fungal, protozoal, helminths
2. Immune mediated - post viral, post streptococcal (rheumatic fever), SLE, drug hypersensitivity
3. Others - sarcoidosis (generalised)

Question 3

Morphology of myocarditis

Answer 3

G:
- enlarged heart, dilated cardiac chambers, flabby myocardium

M:
- variable according to specific causative agent - mononuclear cellular infiltrate, necrosis & edema, polymorphs & micro abscesses, parasites, granulomatous

Question 4

Causes of cardiomyopathy (3)

Answer 4

1. Inherited CMP (gene mutation)
2. Idiopathic CMP
3. Secondary CMP
   - multisystem disease
   - inflammatory/infectious disease
   - toxic/metabolic causes
   - primary muscle disease eg muscular dystrophy

Question 5

Types of cardiomyopathies (3)

Answer 5

1. Dilated (congestive) CMP
2. Hypertrophic CMP
3. Restrictive CMP

Question 6

Features of dilated/congestive CMP

Answer 6

• progressive cardiac dilation
• systolic dysfunction
• caused by: genetics, alcohol, myocarditis, drugs, idiopathic
• results in: progressive heart failure, mitral regurgitation, mural thrombus formation & embolization

Question 7

Features of hypertrophic CMP

Answer 7

• myocardial hypertrophy
• diastolic dysfunction (poorly compliant LV myocardium)
• thickened esp septum - intermittent ventricular outflow obstruction
• caused by: genetics, storage diseases

Question 8

Features of restrictive CMP

Answer 8

• decrease in ventricular compliance - diastolic dysfunction - restriction to cardiac pump
• caused by: amyloidosis, idiopathic
• endocardial fibrosis - fibrosis of ventricular endocardium & subendocardium
• endocardial fibroelastosis - fibroelastic thickening of mural endocardium +/- valvular involvement

Question 9

Complications of cardiomyopathies (4)

Answer 9

1. Heart failure
2. Sudden death
3. Arrhythmias
4. Stroke - thrombus formation, embolus