The effects of enoximone (MDL-17043) on forearm venous circulation in healthy volunteers and patients with heart failure.

Abstract

The effect of intravenous enoximone on forearm venous circulation was studied in ten healthy volunteers (group A) and in ten patients with NYHA class III-IV congestive heart failure (group B). Distensibility of the forearm capacitance vessels was assessed from pressure-volume curves by venous occlusion plethysmography using a mercury-in-rubber strain gauge. Three recordings each at 3-min intervals were obtained before the infusion and again 20 min after completion of the infusion. Venous volume changes (VV) at congesting pressures of 10, 20, and 30 mmHg before and after enoximone were compared. Forearm muscle blood flow was also measured by venous occlusion plethysmography; electrocardiogram, heart rate, and cuff blood pressure were recorded throughout. Enoximone at a dose of 1 mg/kg body weight was infused over 10 min through a peripheral vein in group A and via a central line in group B. In group A, the effect of the injection vehicle was also assessed. VV10, VV20, and VV30 did not differ from baseline values after enoximone in both groups A and B. The vehicle caused a small but significant degree of venoconstriction in group A (VV20, 2.64 +/- 0.9 to 2.48 +/- 0.83 ml/100 ml, P less than 0.05; VV30, 3.47 +/- 1.27 to 3.33 +/- 1.20 ml/100 ml, P less than 0.05), which could be explained by an acute response to local pain from the infusion. This effect was not evident following enoximone, perhaps as a result of its counterbalancing vasodilating action to venoconstriction induced by acute pain.(ABSTRACT TRUNCATED AT 250 WORDS)