Cardiomyopathies in children – inherited heart muscle disease: Overview of hypertrophic, dilated, restrictive and non-compaction phenotypes

Pediatric cardiomyopathies of genetic origin directly involving the heart muscle – i.e. not related to metabolic causes - are rare, yet serious diseases of the heart with an annual incidence of 1.1 to 1.5 per 100,000 children. Cardiomyopathies are a prevalent cause of heart failure and the most common cause of heart transplantation in children older than 1 year of age. Dilated and hypertrophic cardiomyopathy (HCM) have the largest prevalence, whereas restrictive cardiomyopathy and left ventricular non-compaction are very rare. The epidemiology, natural history and prognostic indicators of pediatric cardiomyopathies were poorly understood before the 1990s, and many gaps in knowledge remain to this day. Advances in cardiac imaging and genomic characterization, including genome-wide analysis, are providing fresh insights into the etiology and outcome of children with cardiomyopathy. While morphological and clinical manifestations are similar to those of adult patients, pediatric cardiomyopathies tend to have more severe outcomes and may respond less well to pharmacological treatment. The present review aims to examine familial cardiomyopathies in children, focusing particularly on the risk predictors and outcome of HCM, probably the field with the most impressive advances in recent years.