Effect of Intravenous Pimobendan (UDCG 115 BS) on Hemodynamics and Left Ventricular Volumes in Idiopathic Dilative Cardiomyopathy

Abstract

Acute cardiovascular effects of 5 mg (group I, n = 6) and 10 mg (group II, n = 6) intravenous pimobendan (UDCG 115 BS) were studied by right and left heart catheterizations in patients suffering from idiopathic dilative 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 (HR), and sytemic blood pressure (BP) 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 pimobendan, and from 18.3 +/- 6.2 to 6.2 +/- 3.4 mm Hg (p less than 0.005) by 10 mg pimobendan. Reduction of RAP was only significant in group II (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 at 10 mg pimobendan induced a temporary reduction of mean arterial blood pressure (MAP). An increase in HR occurred only in group I and was merely transient. Left ventricular end-diastolic (EDVI) and end-systolic volume (ESVI) indices were clearly reduced by 5 mg, as well as by 10 mg pimobendan. However, a significant rise of left ventricular ejection fraction (EF) only occurred in group II. On the other hand, left ventricular dP/dtmax was increased significantly in both groups. No adverse effects were noted during acute administration of pimobendan.(ABSTRACT TRUNCATED AT 250 WORDS)