Cardiomyopathy

Cardiomyopathy

·        = Primary or idiopathic diseases involving the myocardium. Diagnosed by excluding other more common causes of heart failure: IHC, hypertension, rheumatic fever, and infectious myocarditis

Primary Cardiomyopathy

Congestive-Dilated Cardiomyopathy

·        Presents as congestive heart failure at any age

·        Men twice as common as women

·        Exclude pre-existing hypertension and alcoholism

·        Macroscopic appearance: greatly dilated ventricles, heart weighs 500 – 1000g (normal is 300g female, 350 g male)

·        Microscopic appearance: patchy interstitial fibrosis, ­­interstitial oedema, hypertrophy of remaining fibres

·        Complications: arrhythmia, mural thrombus, mitral and tricuspid insufficiency

·        Prognosis: progressive disease, no cure

Hypertrophic Cardiomyopathy

·        Disproportionate hypertrophy of the interventricular septum ® ventricular outflow obstruction

·        Familial and non-familial forms

·        Macroscopic appearance: heart weighs 600 – 1300g.  Septum thicker than free wall of left ventricle

·        Microscopic appearance: diffuse hypertrophy of tangled myocytes.  Interstitial collagen

·        Prognosis: poor.  1/3 die from outlet obstruction (can be precipitated by digoxin)

Restrictive Cardiomyopathy

·        Endocardial fibroelastosis: cartilage-like thickening of the left sided endocardium.  Most common < 2

·        Endomyocardial fibrosis: Only tropical Africa. Fibrosis ® thickening of chordae tendinae and aortic valve leaflets

Secondary Cardiomyopathy

·        Alcohol, cobalt, sarcoid (infiltrative granulomatous), amyloid (accumulation of insoluble b pleated proteins derived from immunoglobulins in elderly patients), metastatic carcinoma, storage diseases (eg haemochromatosis), ischaemia

·        Effect of alcohol on the heart:

o   Binge drinking (also exercise and caffeine) ® AF a day later lasting for a day

o   Fibrotic cardiomyopathy

o   Arrhythmia