Dilated cardiomyopathy (DCM) is a disease of the heart muscle in which the left ventricle, and sometimes other chambers, becomes enlarged (dilated) and weakened, significantly reducing its ability to pump blood effectively. It is one of the most common causes of heart failure and a recognised cause of sudden cardiac arrest through ventricular arrhythmias.
DCM can result from genetic variants, viral myocarditis, excessive alcohol consumption, certain medications or chemotherapy agents, nutritional deficiencies, and peripartum changes following pregnancy. In up to 50% of cases no cause is identified (idiopathic DCM), and many of these have an underlying inherited basis. Family screening is important whenever DCM is diagnosed, as relatives may carry the same genetic variant.
Symptoms include breathlessness, fatigue, ankle swelling, and reduced exercise tolerance. In some people, the first presentation of DCM is sudden cardiac arrest due to ventricular tachycardia or ventricular fibrillation.
Treatment focuses on heart failure medication (ACE inhibitors, beta-blockers, aldosterone antagonists, SGLT2 inhibitors) and, for those at high arrhythmia risk, ICD implantation. Those with DCM and a wide left bundle branch block may benefit from Cardiac Resynchronisation Therapy (CRT). In severe refractory cases, heart transplantation may be considered. Referral to an inherited cardiac conditions service is appropriate when a genetic cause is suspected.
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