METHODS AND RESULTS: The study was a stand-alone, double-blind, randomized parallel group comparison of
ibopamine (100 mg 3 times daily) and placebo in 59 patients with New York Heart Association functional class III-IV
heart failure. Patients were clinically stable on
drug treatment, including an
angiotensin-converting enzyme inhibitor, and they were randomized to
ibopamine (n = 29) or placebo (
n = 30). Assessments were performed at baseline and after 3 months of treatment, and included measurement of peak oxygen consumption, plasma
neurohormones, ambulatory arrhythmias, and heart rate variability. At baseline, the two groups were well matched, including age (mean, 63 years), left ventricular ejection fraction (0.23), and peak oxygen consumption (15.4 mL/min/kg). After 3 months, four patients had dropped out of the study because of progressive
heart failure (
ibopamine, n = 1; placebo, n = 3; not significant) and two because of side effects (n = 1/1). Exercise time and peak oxygen consumption were not significantly affected (exercise time:
ibopamine, +54 [95% confidence interval, -12, 120] seconds; placebo, +19 [-42, 81] seconds; peak oxygen consumption:
ibopamine, +0.3 [-0.5, 1,2] mL/min/kg; placebo, +0.2 [-0.7, 1.0] mL/min/kg). Plasma
neurohormones and ventricular arrhythmias during ambulatory monitoring were also unaffected. In contrast, heart rate variability parameters, in particular those associated with vagal tone (rMMSD, high-frequency power), significantly increased after 3 months on
ibopamine (P = .01 vs placebo).
CONCLUSIONS: In this group of patients with clinically stable moderate to severe chronic
heart failure, only a marginal and statistically nonsignificant effect on clinical parameters was observed after 3 months of treatment with
ibopamine. Heart rate variability parameters, however, were significantly affected by
ibopamine, despite the absence of an effect on plasma
neurohormones.