Heart failure in infants and children

• Based on strong research evidence, pediatric HF is a clinical syndrome that occurs when cardiac output is not sufficient to meet the metabolic demands of the body. • Strong research evidence suggests that although there are many specific causes of HF, only a few primary mechanisms operate in all patients regardless of age (volume loading, afterload stress, disorders of rhythm, and impaired myocardial contractility). (2) • Based on some research evidence and consensus, pediatric HF results from a less well understood set of signaling pathways that involves the sympathetic nervous system, inflammation, so-called neuroendocrine hormones, (10)(11)(12)(18)(19) and cachexia. (4)(5)(20) These pathways represent a complex interaction between maladaptive and beneficial actions. • Based on some research evidence and consensus, the clinical presentation of HF is multifaceted and unique in children. Current medical management addresses noncardiac systemic disease and treats primary cardiac problems by surgery or medical strategies aimed at reducing preload and afterload. (21) • The medical therapies for managing HF, including blockade of the sympathetic nervous system, afterload reduction with vasodilators, and treatment of cachexogenic pathways, were pioneered in adults and have not been well studied in children. Presently, most pediatric HF treatments depend on experience and reason rather than on evidence-based studies in infants and children. • The validation of a pediatric system of HF classification and the acceptance of surrogate endpoints for HF studies are essential for the field to move toward reducing morbidity and mortality in children who experience HF.