Most common form of cardiomyopathy, characterised by ventricular chamber enlargement and contractile dysfunction with normal left ventricular wall thickness

Aetiology

• Most patients present between the third and sixth decades of life
• Familial DCM is associated with mutations in genes responsible for cytoskeleton or proteins involved in contractions; it is predominantly autosomal dominant
• Sporadic DCM can be caused by multiple conditions:
  • Toxins e.g. drugs, alcohol, chemotherapy (doxorubicin)
  • Myocarditis
  • Autoimmune disorders
  • Endocrine disorders
  • Neuromuscular disorders

Pathophysiology

• DCM is characterized by enlarged ventricular size, with normal ventricular wall thickness and systolic dysfunction
• Heart becomes ‘floppy’ with reduced ejection fraction

Clinical features

Symptoms

The most common symptoms are those related to heart failure

• Exertional dyspnoea
• Orthopnoea
• Paroxysmal nocturnal dyspnoea
• Peripheral oedema

Other symptoms relate to consequences of the cardiomyopathy

• Arrhythmia (atrial fibrillation or ventricular tachycardia)
• Conduction disturbances
• Sudden cardiac death

Signs