Acute and long-term hemodynamic effects of pimobendan (UD-CG 115 BS) in comparison with captopril.

The acute and long-term hemodynamic efficacy of the positive inotropic and vasodilatory drug pimobendan (5 mg b.i.d.) was compared with that of the angiotensin converting enzyme (ACE) inhibitor captopril (25 mg t.i.d.) in a double-blind, randomized study in 20 patients suffering from chronic congestive heart failure (NYHA functional classes II-III). The hemodynamics at rest and under comparable exercise conditions were always obtained on the first and 14th treatment day before and 2 h following drug administration. Under resting conditions, pimobendan reduced the end-diastolic pulmonary arterial pressure measured 2 h after drug administration by 33% (p less than 0.05) and increased the cardiac output by 16% (p less than 0.05). These effects were maintained after a treatment period of 14 days. Following administration of captopril, no significant hemodynamic changes at rest were noted 2 h after the first dose on day 1 and the last dose on day 14. There was, however, a tendency to continuous decline of the end-diastolic pulmonary arterial pressure over the study period. Under comparable work load (median of 25 W), both substances decreased the end-diastolic pulmonary arterial pressure 2 h following the first dose (pimobendan, -38%, p less than 0.01; captopril, -9%, p less than 0.05). The difference in the magnitude of effect between both treatment groups was statistically significant (p less than 0.01). Following a treatment period of 14 days, the end-diastolic pulmonary arterial pressure before drug administration was significantly reduced (-24%, p less than 0.05) only in the pimobendan group, whereas the reduction in the captopril group (-11%) could not be statistically verified.(ABSTRACT TRUNCATED AT 250 WORDS)