Restrictive Cardiomyopathy in Children

Restrictive cardiomyopathy (RCM) is one of the rarest and most rapidly lethal forms of childhood cardiomyopathy. RCM is characterized by diastolic dysfunction with restrictive and reduced ventricular filling. The causes of RCM are significantly different in children compared to adults and often differ based on geography. In children, RCM is typically most often classified as idiopathic, although causative genetic mutations are increasingly being identified. Secondary causes of RCM in children are rare. The age and clinical presentation of children with RCM vary significantly. Symptoms range from absent to severe including heart failure, syncope, embolic events, or sudden cardiac death. RCM is usually diagnosed by echocardiogram and confirmed by cardiac catheterization. Medical management is limited and is primarily symptom based with judicious use of diuretics to improve pulmonary and systemic venous congestion. No current medical or mechanical therapies improve diastolic dysfunction or improve transplant-free survival, which remains poor. This is likely due to the many different underlying mechanisms that can lead to the restrictive physiology phenotype. However, the overall outcomes of children with RCM have significantly improved due to the strategy of earlier heart transplantation. The timing for listing for heart transplant remains controversial and is multifactorial. Posttransplant outcomes of children with RCM are similar to posttransplant outcomes in other forms of cardiomyopathy. Until a better understanding of the mechanistic pathways leading to RCM can result in improved risk stratification and/or disease-modifying therapies, cardiac transplantation remains the definitive therapy for children with RCM.