Definition
Dilated cardiomyopathy (DCM) is characterised by dilatation and impaired contraction of the left and sometimes the right ventricle leading to progressive left-sided later right-sided heart failure. Functional mitral or tricuspid regurgitation may occur.
Causes
• Alcohol.
• 25% cases are inherited as autosomal dominant trait.
• Autoimmune reaction to viral myocarditis.
• Ischaemic heart disease.
• Nutritional—thiamine (Vitamin B1) deficiency.
• Muscular dystrophies—Duchenne or Becker’s.
• Others—thyrotoxicosis, pregnancy, infiltrative disease (haemochromatosis, sarcoidosis).
• Idiopathic in many cases.
Clinical Features
Symptoms
• Breathlessness on exertion.
• Features of heart failure—palpitation, swelling of legs, fatigue.
• Sporadic chest pain.
• Sudden death.
Signs
• Signs of cardiac failure (left or right or biventricular)
• Arrhythmia.
Investigations
• ECG usually shows nonspecific changes.
• Chest X-ray (shows cardiomegaly).
• Echocardiography.
Treatment
Mainly of heart failure.
1. Rest, salt and fluid restriction, avoidance of exercise.
2. Medical therapy—
–– β-blockers.
–– ACE inhibitors or Angiotensin receptor blocker.
–– Diuretics.
–– Nitrates.
–– Antiarrhythmic drugs if arrhythmia—amiodarone.
3. In some patients—implantation of ICD.
4. Treatment of primary cause, if any.
5. Cardiac transplantation may be indicated.