Dilated cardiomyopathy is characterised by dilation and poor contraction of either the left ventricle, or both ventricles (ejection fraction < 40%).

Epidemiology: Most patients present between the third and sixth decades of life

Causes

• Ischaemic changes can over time manifest with DCM, particularly post-myocardial infarction
• Hypertensive
• Genetic and congenital - may be related to familial dilated cardiomyopathy, however some sporadic gene mutations may be responsible for idiopathic cases
• Toxin-related - excessive alcohol consumption leads to myocardial dysfunction and subsequent DCM. Cocaine is also associated with ischaemia and DCM. Other medications which lead to cardiomyopathy include anthracycline chemotherapy (Doxorubicin), Cyclophosphamide, antiretroviral drugs (Zidovudine), Chloroquine and Clozapine.
• Infiltrative - haemochromatosis, amyloidosis and sarcoidosis are known to cause DCM
• Peripartum - a rare cause of DCM, with unclear aetiology
• Thyrotoxicosis - the exact mechanism of this is uncertain, but thought to be related to the effects of thyroid hormone on cardiac function
• Infectious - DCM can occur secondary to myocarditis, or as a direct result of infection from HIV, Lyme disease and Chagas disease
• Stress induced cardiomyopathy (Takotsubo cardiomyopathy) refers to transient left ventricular ballooning precipitated by intense psychologic stress. Almost all patients recover completely
• Idiopathic - when other potential causes have been ruled out

PC

The most common symptoms are those related to heart failure

• Exertional dyspnoea
• Orthopnoea