Cardiomyopathy in childhood, mitochondrial dysfunction, and the role of L-carnitine.

Cardiomyopathy in childhood is associated with high morbidity and mortality rates. Many metabolic causes have been identified, including genetic or acquired defects in mitochondrial energy production affecting beta-oxidation, carnitine transport, and the electron transport chain. Combining conventional inotropic and antiarrhythmic therapy with metabolic interventions has improved overall outcome. L-carnitine, a natural substance involved in mitochondrial transport of fatty acids, is one such therapy and plays a central role in the regulation of the inner mitochondrial supply of free coenzyme A. Carnitine deficiency can be caused by both genetic and environmental causes with resultant signs and symptoms of metabolic disease, including cardiomyopathy. Administration of L-carnitine can result in improvement or resolution of the cardiomyopathy.