An Update on Pediatric Cardiomyopathy

This review summarizes the clinical characteristics and updated outcomes of primary pediatric cardiomyopathies including dilated (DCM), hypertrophic (HCM), and restrictive cardiomyopathy (RCM), and briefly discusses left ventricular non-compaction (LVNC) and arrhythmogenic cardiomyopathy (ACM), primarily arrythmogenic right ventricular cardiomyopathy (ARVC).

Pediatric cardiomyopathies are diseases of the heart muscle with an estimated annual incidence of 1.1-1.5 cases per 100,000. They are progressive in nature and are frequently caused by a genetic mutation causing a structural abnormality in the myocyte. Dilated cardiomyopathy, characterized by left ventricular dilation and systolic dysfunction with normal left ventricular wall thickness, accounts for about 50-60% of all pediatric cardiomyopathy cases. This is followed by hypertrophic cardiomyopathy accounting for about 40%, characterized by abnormally thickened myocardium in the absence of another cause of hypertrophy with non-dilated left ventricle. Left ventricular non-compaction and restrictive cardiomyopathy each account for about 5% of the cases. Genetic mutations play a dominant role in the development of pediatric cardiomyopathies. While treatment for congestive heart failure and arrhythmias alleviates symptoms, it has not been shown to reduce the risk of sudden death. The 5-year transplant-free survival of DCM, HCM, RCM, and LVNC are 50%, 90%, 30%, and 60% respectively. Pediatric cardiomyopathies while not common they are a significant cause of morbidity and mortality in afflicted children. Dilated forms are the most common followed by hypertrophic, left ventricular non-compaction, and restrictive cardiomyopathies. Arrhythmogenic cardiomyopathies tend to be diagnosed later in the teenage years. Treatment typically follows adult recommendations for which there is significantly more data on treatment benefits, although the indications for ICD placement in children remain even less clear, other than for secondary prevention.