Long-term treatment with oral enoximone for chronic congestive heart failure: The European experience

The long-term safety and efficacy of the inotropic/ vasodilatory agent enoximone (50 to 100 mg 3 times daily) were evaluated in 30 patients with chronic congestive heart failure (New York Heart Association classes II to IV). Nineteen patients had idiopathic dilated cardiomyopathy and 11 had ischemic heart disease. Patients were receiving maintenance therapy of digitalis and diuretics. Cardiac function was assessed at 12 week intervals (physical examination, exercise testing, chest x ray, echocardiography, radionuclide angiography, 24-hour Holter monitoring and blood chemistry). During a mean follow-up of 40 weeks, 6 patients died, due to noncardiac (n = 1) and sudden death (n = 1) and to cardiac failure (n = 4) within 36 weeks of drug treatment. In the remaining patients New York Heart Association class improved in 18, was stationary in 5 and deteriorated in 1. Exercise capacity increased during the first 26 weeks and was maintained improved thereafter. Clinical improvement appeared not to wane with time. No change in heart rate, blood pressure and cardiothoracic ratio was observed. Echocardiographic left ventricular dimensions did not change significantly; however, the fractional shortening increased from baseline (14%) to 19% after 12 weeks, 17% after 26 weeks and 21% after 52 weeks (p < 0.05). The preejection period/left ventricular ejection time ratio decreased from 0.74 to 0.35, 0.44 and 0.43 (p < 0.05), respectively. There was an increase in radionuclide ejection fraction from 23% to 27% (difference not significant). Hemodynamic monitoring in 6 patients showed an increase in cardiac output from baseline (2.4) to 3.6 liters/min/m 2 (p < 0.001) after 52 weeks of drug treatment; pulmonary wedge pressure decreased from 25.8 to 16.6 mm Hg (p < 0.001). The drug was well tolerated. Twenty-four-hour Holter monitoring did not show a change in arrhythmia profile. No major alteration in blood chemistry was observed. If initially tolerated, enoximone appears to be useful in the long-term treatment of patients with chronic congestive heart failure.