Cardiocirculatory actions of trimazosin and sodium nitroprusside in ischemic heart disease.

Abstract

Although postload-reducing drugs are effective vasodilators in chronic congestive heart failure, the clinical application of the approach to ambulatory patient management remains difficult. We compared the hemodynamic effects of the new oral systemic vasodilator trimazosin (TZ) with those of nitroprusside (NP). Both TZ (172 mg) and NP (46 microgram/min) decreased mean blood pressure modestly (P less than 0.001), while causing considerable decline in elevated left ventricular filling pressure (TZ from 30 to 24 mm Hg; NP from 31 to 20 mm Hg; both P less than 0.001). TZ also raised the low cardiac index (CI) of 2.02 to 2.59 1/min/M2 (P less than 0.001), whereas NP elevated CI from 2.16 to 2.96 1/min/M2 (P less than 0.001). Both drugs lowered (P less than 0.05) total systemic vascular resistance and pressure time/minute while enhancing (P less than 0.01) stroke work index. The drugs diminished forearm venous tone (P less than 0.02) and forearm vascular resistance (P less than 0.01) concomitantly with elevation of forearm blood flow (P less than 0.05). Thus, TZ induced qualitatively similar marked augmentation of cardiac function to that by NP. These encouraging hemodynamic findings indicate that TZ may be beneficial to patients undergoing ambulatory vasodilator therapy of severe chronic congestive heart failure.