Reduction in left ventricular volume and improvement in hemodynamics following intravenous administration of pimobendan (UDGG 115 BS) in dilated cardiomyopathy

: Acute cardiovascular effects of 5 mg (group I, n = 6) and 10 mg (group II, n = 6) i.v. pimobendan (UDCG 115 BS) were studied by right and left heart catheterizations in patients suffering from idiopathic dilated cardiomyopathy (NYHA II and III). Before and 2.5 h after application of pimobendan left ventricular volumes and left ventricular dP/dtmax were evaluated by left heart catheterization. Right atrial pressure (RAP), pulmonary capillary wedge pressure (PCP), cardiac output (CO), heart rate, and systemic blood pressure were assessed before and 2.5, 4, and 6 h after administration of pimobendan. PCP was reduced from 12.2 +/- 7.5 to 8.3 +/- 7.1 mm Hg (p less than 0.05) by 5 mg of pimobendan, and from 18.3 +/- 6.2 to 6.2 +/- 3.4 mm Hg (p less than 0.005) by 10 mg of pimobendan. Reduction of RAP was significant only in group II (from 6.2 +/- 3.2 to 1.2 +/- 0.9 mm Hg; p less than 0.05). In contrast to other hemodynamic parameters, the significant increase of CO exhibited no dose-dependency. Only 10 mg of pimobendan induced a temporary reduction of mean arterial blood pressure. An increase in heart rate occurred only in group I and was merely transient. Left ventricular end diastolic and end systolic volume indices were clearly reduced by 5 mg as well as by 10 mg of pimobendan. A significant rise of left ventricular ejection fraction occurred only in group II. However, left ventricular dP/dtmax was increased significantly in both groups. No adverse effects were noted during acute administration of pimobendan. Therefore, intravenous pimobendan may be a useful drug in the treatment of acute cardiac failure.