Oral enoximone therapy in chronic heart failure: a placebo-controlled randomized trial. The Western Enoximone Study Group.

In a parallel study design, 164 patients with New York Heart Association Functional class II or III heart failure were randomized to receive either enoximone given as 50 mg three times a day, or 100 mg three times a day, or a matching placebo. All patients were receiving digitalis and/or diuretics and had left ventricular ejection fractions less than or equal to 45. Exercise tests were performed after 1, 4, 8, and 12 weeks of treatment. Enoximone produced significantly greater increases in exercise time than placebo treatment at weeks 4 and 8 (p = 0.012, p = 0.029, respectively) but not after 12 weeks. Left ventricular ejection fraction increased significantly after the first dose of enoximone but not after 12 weeks of long-term therapy. Heart failure symptoms and the physicians' evaluations of cardiac status were significantly improved in both enoximone therapy groups during the first 4 weeks of evaluation when compared with evaluations of cardiac status in the placebo group. Diuretic doses were increased more frequently for patients who were receiving a placebo. Adverse events were reported with similar frequency in the placebo and 50 mg enoximone treatment groups; 100 mg enoximone resulted in a significantly greater incidence of adverse events. Mean heart rate and ventricular ectopic activity were not significantly different among the three treatment limbs. Enoximone appears to improve exercise tolerance, ventricular function, and symptoms of heart failure for 4 to 8 weeks. Heart rate, ventricular ectopic activity, and mortality rate were not increased.(ABSTRACT TRUNCATED AT 250 WORDS)