Long-term enoximone therapy in unstable chronic heart failure.

Long-term safety and efficacy of oral enoximone were evaluated in 32 patients with unstable chronic heart failure despite digitalis, diuretics, and vasodilator therapy. Oral enoximone, 75-150 mg t.i.d. was given for an average of 32 weeks. At baseline, 21 patients were in NYHA functional class IV, 10 patients in class III, and 1 patient in class II. Within 12 weeks, 14 of 20 patients surviving for more than 26 weeks had improved by at least one functional class. Hemodynamic data showed an 18% increase of cardiac index and a 34% decrease of diastolic pulmonary artery pressure. Echocardiographic recordings revealed an increase of fractional shortening from 13.9 +/- 7 to 15.6 +/- 5% after 12 weeks and 20.3 +/- 5% after 26 weeks. The 1-year survival rate was 40%. Sudden death occurred in three patients and pump failure in 11 patients. No serious side effects were reported. Holter monitoring did not show a significant proarrhythmic drug effect. Thus, long-term enoximone therapy is safe and produces sustained clinical and functional improvement in unstable chronic heart failure. However, overall survival appears not to be influenced in this patient group.