A classification serves to bridge the gap between ignorance and knowledge. With increasing understanding of aetiology and pathogenesis the difference between cardiomyopathy and specific heart muscle disease has become indistinct. The original classification described three types which have become established clinical entities and this terminology has been preserved. This condition is characterized by dilatation and impaired contraction of the left or both ventricles. Histology is nonspecific.
Presentation is usually with heart failure which is often progressive.
Arrhythmias, thromboembolism and sudden death are common and may occur at any stage. Typically the left ventricular volume is normal or reduced. Systolic gradients are common. Familial disease with autosomal dominant inheritance predominates. Mutations in sarcomeric contractile protein genes cause disease.