[Apparently idiopathic primary myocardiopathies in children. The role of metabolic etiology].

Thirty-three children presenting with "primitive" cardiomyopathy observed from January 1984 to December 1985 underwent a protocol of investigations consisting of histo-enzymatic study of the deltoid muscle, metabolic studies (glucose, free fatty acids, lactate, pyruvate, 3-hydroxybutyrate, aceto-acetate, carnitine, amino-acids blood levels after a 15 hour-fast; urinary organic acids chromatography) and a study of the fatty acids oxidation in cultured fibroblasts. In all children cardiac involvement was predominant and had been the cause for hospitalization. Cardiomyopathies of the hypertrophic type have an early onset, most often are part of a complex picture of extra-cardiac involvement and frequently have a lethal evolution. On the contrary, hypokinetic dilated cardiomyopathies are most often isolated, have a later onset and a less severe course. In 2 cases, an early hypokinetic dilated cardiomyopathy evolved toward hypertrophy. Peripheral muscular involvement is very frequent (lipidosis, mitochondrial aggregates or specific aspects) (60% of cases) in dilated as well as hypertrophic types. A precise etiological diagnosis or a strong presumption was possible in 12 of 33 cases: 2 with hereditary deficiency of the fatty acids beta-oxidation, 1 carnitine systemic deficiency, 1 Friedreich ataxia, 1 central core disease, 1 coxsackie B1 myocarditis, 6 strong suspicions of respiratory chain deficiency.