Chronic afterload reduction in infants and children with primary myocardial disease.

The purpose of this study was to determine the long-term effects of chronic afterload reduction with oral hydralazine therapy in patients with primary myocardial disease (PMD). Twenty-six children aged 3 to 48 months with the diagnosis confirmed by M-mode and two-dimensional echocardiograms and angiograms were given digitalis and diuretics. Fourteen of these patients also received hydralazine orally in doses up to 4.0 mg/kg/day in four divided doses. Echocardiograms were initially repeated at 1- to 3-month intervals and subsequently at 6-month intervals. Long-term follow-up data were available in 10 patients given hydralazine and eight control patients; the follow-up interval ranged from 3 to 48 months. In the hydralazine group the shortening fraction rose from 14.5 +/- 4.9 to 23.2 +/- 7.5 (P less than 0.01), and the ratio of pre-ejection period to ejection time (0.52 +/- 0.05 to 0.35 +/- 0.06, P less than 0.001) and left ventricular size, normalized to body surface area (116 +/- 7 to 87 +/- 21, P less than 0.01), decreased. Significant improvement was demonstrated by echocardiography after 12 months of hydralazine therapy. There was no significant change in any of these values in the control group. We conclude that hydralazine therapy is a useful adjunct in the management of primary myocardial disease in infancy and childhood.