Positive inotropic effects of hydralazine in human subjects: comparison with prazosin in the setting of congestive heart failure.
Hydralazine possesses positive inotropic properties in animal model preparations. To determine whether this vasodilator elicits a positive inotropic response in the failing human ventricle, hydralazine, 75 or 100 mg, was administered orally to 14 patients with left ventricular dysfunction and congestive heart failure; the results were compared with those of first-dose prazosin at 5 and 10 mg. The duration of the preejection period and the isovolumic developed pressure/duration of isovolumic contraction (delta P/delta t) were used as indexes of inotropy. Prazosin did not effect a significant response in the duration of the preejection period or in the delta P/delta t. Hydralazine significantly shortened the preejection period and increased the delta P/delta t over 8 hours after administration; these data suggest that hydralazine elicits a positive inotropic response in the failing human ventricle.
D004305:Dose-Response Relationship, Drug; D006333:Heart Failure / Q000188:drug therapy*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006830:Hydralazine / Q000627:therapeutic use*; D009200:Myocardial Contraction / Q000187:drug effects*; D011224:Prazosin / Q000627:therapeutic use*; D011669:Pulmonary Wedge Pressure / Q000187:drug effects; D011799:Quinazolines / Q000627:therapeutic use*; D013318:Stroke Volume / Q000187:drug effects
D011799:Quinazolines; D006830:Hydralazine; D011224:Prazosin