Factors influencing the persistence of shunting within 24 hours of catheter occlusion of the ductus arteriosus.

Abstract
The results of the medical treatment of primary pulmonary hypertension are usually very poor. A case of severe primary pulmonary hypertension in chronic heart failure was treated with the calcium antagonist nifedipine, a powerful vasodilator which acts directly on vascular smooth muscle. Nifedipine, administered in a dose of 20 mg sublingually, caused a pronounced fall in pulmonary and systemic vascular resistances (54 and 49%, respectively) and a rise in cardiac output (90.3%). Improvement was maintained over a three-month period. These data suggest that nifedipine can be used in the treatment of this condition.