To assess the acute hemodynamic and long-term clinical effects of isradipine, a calcium antagonist of the dihydropyridine class, we performed a double-blind, placebo-controlled parallel study in 19 patients with coronary artery disease (CAD) and stable chronic heart failure (CHF). Their mean age was 56 +/- 5 years, and left ventricular ejection fraction (LVEF) was 0.18 +/- 0.05. Patients were treated with diuretics and digoxin only. All were clinically stable and in sinus rhythm. The acute hemodynamic study showed that (intravenous) isradipine increased cardiac index (+36%) and stroke volume index (+30%) (both P < 0.001), while systemic vascular resistance (-33%) and mean arterial pressure (-10%) decreased (both P < 0.005). Filling pressures and heart rate were not affected. Of the 19 patients, 17 completed the 12 week study; 2 patients on placebo (1 death, 1 side-effects) but no patient on isradipine (5 mg 3 times daily) dropped out. After 12 weeks, peak oxygen consumption (VO2), LVEF, echocardiographic indices, and other clinical parameters were unaffected by treatment. Repeat invasive hemodynamic measurements showed that the initial improvement by isradipine was not present anymore. In conclusion, despite a beneficial acute hemodynamic effect, isradipine has no favorable clinical influence during prolonged treatment in patients with mild to moderate CHF.