Clinical review - Aetiology, diagnosis, investigation, and management of the cardiomyopathies

A molecular pathogenesis for dilated and hypertrophic cardiomyopathy is beginning to be elucidated. More than half of patients with hypertrophic cardiomyopathy and a quarter of patients with dilated cardiomyopathy have familial disease. Known genetic mutations occur in only about a half of families affected by hypertrophic cardiomyopathy and considerable genetic diversity may give rise to similar phenotypes Differences in phenotype expression within affected families may reflect other modifying genetic or environmental factors Diagnosis of hypertrophic cardiomyopathy is based on the echocardiographic finding of unexplained thickening of parr or all of the left ventricular wall with a normal or small sized cavity. Within affected families, however, electrocardiography is more sensitive than echocardiography in detecting the disorder. Diagnosis of dilated cardiomyopathy is based on echocardiographic recognition of left ventricular dilatation and reduced contractile function after exclusion of valvular or coronary disease.