HYDRALAZINE IN THE MANAGEMENT OF LEFT-VENTRICULAR FAILURE

This study was designed to compare the short and long-term effects of hydralazine when used as a vasodilator in the treatment of left ventricular failure. The hemodynamic changes after the acute intravenous and long-term oral administration of hydralazine were compared in a group of 16 patients with left ventricular failure (14 patients with congestive cardiomyopathy and two with hypertensive heart failure). After 20 mg of hydralazine, administered intravenously there was a 56 percent increase in stroke volume (P < 0.001) and a 27 percent decrease in left ventricular filling pressure (P < 0.001) but no significant change in heart rate despite a 16 percent decrease in mean arterial pressure (P < 0.001). Seven of the patients then took hydralazine, 200 to 300 orally/day for 4 to 6 weeks. They were restudied during therapy with the drug and again 48 to 72 hours after stopping it. After the period of oral treatment there was a 71 percent increase in stroke volume (P < 0.001) and a 25 percent decrease in left ventricular filling pressure (P < 0.05). Forty-eight to 72 hours after discontinuation of drug administration, left ventricular filling pressure had returned to the control value (-3 percent, P < 0.05), but the stroke volume was still slightly elevated (14 percent, P < 0.05). The results show that oral administration of hydralazine can produce sustained benefit with changes similar to those induced by intravenous administration. The second control study after discontinuation of hydralazine therapy confirmed that these changes had been induced by and were dependent on the drug. © 1979.