Only small groups of children, and especially infants, with hypertrophic cardiomyopathy have been analysed thus far. The clinical features, and the evolution, of this potentially heterogeneous disease, therefore, remain to be clarified. We describe the clinical profile of 35 patients with hypertrophic cardiomyopathy, 18 being younger than 1 year when first seen. Electrocardiography, chest radiography and echocardiography (m-mode, cross-sectional and color-Doppler) were performed in all patients. Ambulatory electrocardiographic monitoring was performed in 20 patients, and cardiac catheterization in 5 patients. The duration of follow-up was 6.6 years, and ranged from 1 month to 15 years. First-degree relatives of 9 infants and 13 children underwent complete echocardiographic evaluation.
Inheritance, along with presence of congestive heart failure, cyanosis, cardiac enlargement and right ventricular hypertrophy proved to be different in infants who presented with hypertrophic cardiomyiopa-thy as compared with those presenting in childhood. In contrast, echocardiography showed that the distribution of ventricular hypertrophy was similar in the two groups. Intractable congestive heart failure, which was the commonest cause of death, was an ominous prognostic sign in infants. Older children, however, tended to die suddenly. Spontaneous resolution of severe ventricular hypertrophy occurred in four infants of non-diabetic mothers within their first 6 months of age. We conclude that hypertrophic cardiomyopathy may represent a constellation of disease entities. The observed spontaneous resolution in 4 infants may represent a new form of the syndrome which carries a good prognosis.