Effect of trimazosin on hemodynamics in chronic heart failure.

The effect of the oral vasodilator trimazosin on hemodynamics in 16 patients with chronic left ventricular failure was compared with placebo in a double-blind, randomized study. Eight patients received trimazosin 100 to 300 mg, and 8 received placebo. Over the 6-hr period after medication trimazosin caused no significant change in heart rate, stroke work index, or pulmonary vascular resistance, but there were significant reductions in mean arterial pressure (p less than 0.05), mean right atrial pressure (p less than 0.01), mean pulmonary artery pressure (p less than 0.01), mean pulmonary capillary wedge pressure (p less than 0.01), and systemic vascular resistance (p less than 0.01), and significant increases in stroke index (p less than 0.05) and cardiac index (p less than 0.05). None of 8 patients improved after placebo, whereas 5 of 8 patients (63%) had a good or excellent hemodynamic response after trimazosin (p = 0.006). Four of 4 patients who received 300 mg of trimazosin had a good or excellent response. Trimazosin is a long-acting orally effective vasodilator which improves ventricular function in patients with left ventricular failure.