RESUMO
This study was undertaken to evaluate the cardiac function determined by echocardiography, heart and chest X-rays and electrocardiogram [ECG] in a group of 15 infants and children with congenital hypothyroidism prior to and after thyroxine therapy. Their ages varied from 1 to 30 months, 6 cases were males and 9 were females. Prior to therapy, the study revealed that 40% of these patients had murmurs, 80% had ECG abnormalities, 66% had radiological enlargement of the cardiac silhouette, 20% had evidence of myopathic changes, mainly of the obstructive type, and all the subjects had small to moderate pericardial effusion. After full replacement therapy, these abnormalities reversed to normal, except for one patient with a persistent mild posterior effusion and an associated pulmonary stenosis. No significant abnormality in cardiac chamber dimensions or indices of myocardial function was detected among the hypothyroid children, prior to therapy or after re-establishment of normal thyroxine concentrations with exogenous hormone. The study revealed that the cardiac abnormalities observed in this study did not compromise the cardiac function and reversed to normal after full replacement therapy