Dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is a form of cardiomyopathy characterised by dilation of all four heart chambers, in the absence of ischaemic heart disease, hypertension, valvular disease, and congenital heart disease. The ejection fraction is <45% and the left ventricular end-diastolic volume is >117% of predicted based on body surface area.

DCM is the most common cardiomyopathy, affecting 1/250. The prognosis is poor with a 5-year survival rate of 50%.

Etiology

• Idiopathic
• Familial (genetic) – mutations in cytoskeletal, sarcomeric, nuclear, etc. proteins
• Secondary
  • Myocarditis
  • Pregnancy (peripartum DCM)
  • Alcohol
  • Infiltration (sarcoidosis, amyloidosis)
  • Cardiotoxic drugs

Pathomechanism

Dilation of the chambers causes systolic heart failure.

Clinical features

Patients can be asymptomatic. Symptomatic patients have features of right and/or left-sided heart failure, including fatigue, weakness, exercise intolerance, chest pain, palpitations, and tachycardia.

Diagnosis and evaluation

X-ray shows cardiomegaly, and possibly signs of pulmonary oedema or congestion. Echocardiography shows dilation of all four chambers, decreased EF, and secondary mitral and tricuspid regurgitation.

MRI is the gold standard for evaluation, as it can measure the volumes of the chambers in addition to showing the dilatation. It’s also helpful in the evaluation of myocarditis, a common cause.

Treatment

There is no specific treatment for DCM. If there’s an underlying disease, it should be treated. Treatment for heart failure is often necessary. Implantation of ICD is important to prevent sudden cardiac death by V-fib. Heart transplant is the only curative treatment.