Influence of enoximone and UDCG-115 on coronary hemodynamics in idiopathic dilated cardiomyopathy.

Coronary hemodynamics were studied in 24 patients with idiopathic dilated cardiomyopathy and in 17 patients without any significant heart disease under resting conditions using the argon method. Neither myocardial blood flow normalized for 100 g muscle tissue nor myocardial oxygen consumption per minute (MVO2) or oxygen supply-demand ratio were different between these 2 groups of patients. When enoximone (1 to 2 mg/kg body weight) was given intravenously in patients with idiopathic dilated cardiomyopathy, myocardial oxygen consumption decreased by only 8% (difference not significant), whereas a significant (p less than 0.05) 26% decrease of myocardial oxygen consumption was observed after UDCG-115 (1.25 mg/hour intravenously). However, with both substances the oxygen supply-demand ratio significantly increased from 1.46 +/- 0.10 to 1.57 +/- 0.20 (p less than 0.025; enoximone) and from 1.40 +/- 0.08 to 1.56 +/- 0.19 (p less than 0.05; UDCG-115), respectively. It is concluded from these data that (1) resting coronary hemodynamics related to a unit of myocardium are not different between normal and idiopathic dilated cardiomyopathy, and (2) phosphodiesterase inhibitors exert beneficial effects on coronary hemodynamics by improving the oxygen supply-demand ratio.