Overview
Dilated cardiomyopathy (DCM) describes the enlargement and dilation of one or both ventricles leading to an inability of the heart to pump properly (heart failure). It is the most common form of cardiomyopathy.
DCM can develop secondary to left ventricular failure or secondary to a cause listed below. The heart chambers become dilated and increases in end-systolic and end-diastolic volumes lead to wall thinning and dilatation.
Causes
- Idiopathic
- Ischaemia
- Myocarditis and its causes
- Drugs and toxins:
- Doxorubicin
- Alcohol, cocaine, amfetamines
- Hypertension
- Thyrotoxicosis
- Peripartum cardiomyopathy
- Duchenne muscular dystrophy
- Autoimmune disease (e.g. rheumatoid arthritis and systemic lupus erythematosus)
Presentation
Patients present with features of heart failure.
Investigations
Investigations are similar to that of heart failure.
- N-terminal pro-B-type natriuretic peptide (NT-proBNP):
- Elevated
- If >2000ng/L (high) – referral for specialist assessment and echocardiography within 2 weeks
- If 400-200ng/L (raised) – referral for specialist assessment and echocardiography within 6 weeks
- Full blood count (FBC):
- May identify anaemia, which can worsen heart failure
- Urea and electrolytes (U&Es):
- May show hyponatraemia – heart failure can lead to increased water retention and dilution of serum sodium
- ECG – may show:
- Ventricular hypertrophy
- Conduction abnormalities
- Abnormal QRS duration
- Chest x-ray – may show:
- Pulmonary oedema – Kerley B lines
- Cardiomegaly
- Pleural effusions
- Transthoracic echocardiogram:
- Identifies chamber enlargement and wall thinning
Management
Management is essentially the same as heart failure.
