Clinical Efficacy of Pimobendan for Patients with Chronic Heart Failure — A Dose Finding Study by a Multicenter Double Blind Trial —

Pimobendan (UD-CG 115 BS), a benzimidazole pyridazinone derivative, is a new oral inodilator. Its positive inotropic effect is produced both by inhibition of phosphodiesterase (PDE) and by increase in sensitivity of cardiac myofilaments to Ca [1,2], and the vasodilating effect is induced by inhibition of the type III PDE. It is well absorbed after oral administration, and its effect continues for approximately 10 hours. Since it also acts as a calcium sensitizer, pimobendan has been recently spotlighted as a new type of inotropic agent. The present study was designed to investigate the effect of pimobendan and to determine the optimal dose in patients with chronic heart failure (CHF) by a multicenter placebo-controlled double-blind comparison.