In this subchapter we consider cardiomyopathy as a myocardial disorder not caused by hypertension, valvular disease or ischaemia. It is characterised by systolic and, or diastolic dysfunction. The cardiomyopathy may be dilated or hypertrophic. Cardiomyopathy can be due to alcohol, viral infection, or infiltration by amyloid or sarcoid granuloma. This list is not exhaustive. There might be fibrosis or eosinophilic heart disease. Infiltrative disease commonly leads to arrhythmia and mays cause sudden death.
Cardiac sarcoidosis for instance may result in atrioventricular block or ventricular rhythm disturbance. Cardiac sarcoidosis has a high rate of sudden death (see also the respiratory chapter).
This type of cardiomyopathy may result from myocarditis, alcohol abuse, be idiopathic or even congenital. Medication such as Adriamycin and radiotherapy delivered to the left chest are possible cause of dilated cardiomyopathy. Symptoms are those of exercise intolerance, fatigue and breathlessness. The condition may remain stable for prolonged period or be progressive despite optimal management. Medication usually includes an ACE inhibitor or Angiotensin II Receptor Blocker (ARB). Dilated cardiomyopathy can lead to sudden death.
There is a high risk of atrial or ventricular arrhythmia and embolism. Right ventricular cardiomyopathy is frequently arrhythmogenic.
Previously called hypertrophic obstructive cardiomyopathy (HOCM), this is hypertrophic cardiomyopathy not due to hypertension or outflow obstruction such as exists in aortic stenosis. It has a genetic etiology with multiple genes identified. It is often asymmetrical. Outflow obstruction may result and this will be made worth by volume depletion or catecholamines release. Ventricular arrhythmias are common. Beta-blockers are useful in limiting the risk of obstruction.