Primary restrictive cardiomyopathy in childhood

Restrictive cardiomyopathy is one of the rarest forms of cardiomyopathy in childhood and is associated with very poor prognosis (median transplant-free survival approximately 2 years). Little progress has been made in our understanding of the etiology of this condition, and most cases are considered ‘idiopathic’ in nature. No strong predictors of outcome have been identified and sudden death is common, even among those with few symptoms. Disappointingly, no effective therapies have emerged other than heart transplantation. Studies of familial cases suggest genetic and phenotypic overlap with other forms of cardiomyopathy, especially hypertrophic cardiomyopathy. Future research priorities include more careful delineation of phenotype(s), search for genetic etiologies and molecular mechanisms of disease, and studies to identify prognostic factors. Given the rarity of this condition, future studies will require collaboration among large numbers of centers following the models developed by the US Pediatric Cardiomyopathy Registry and the National Australian Childhood Cardiomyopathy Study.