Invasive pharmacodynamic characterization of combined ibopamine and calcium blocker therapy for heart failure

STUDY OBJECTIVE: To determine the acute hemodynamic response of single-dose coadministration of ibopamine plus nifedipine or diltiazem in patients with New York Heart Association functional class (NYHA FC) II-III congestive heart failure. DESIGN: A single-blind, placebo-controlled, two-paired, crossover study. SETTING: Cardiology clinics at two large teaching hospitals. PATIENTS: Eight patients with NYHA FC II-III congestive heart failure who met the inclusion criteria were selected randomly. INTERVENTIONS: All patients underwent right heart catheterization. Day 1 consisted of concomitant calcium channel blocker plus placebo, with cardiac and peripheral hemodynamic recordings from 30 minutes-24 hours. The design was equivalent on day 2, with single-dose administration of ibopamine plus calcium channel blocker. MEASUREMENTS AND MAIN RESULTS: Single-dose nifedipine-diltiazem augmented cardiac output and stroke volume secondary to decreasing systemic vascular resistance. The nifedipine-ibopamine and diltiazem-ibopamine subgroups demonstrated relatively equal hemodynamics, augmenting cardiac index (nifedipine 43%, p < 0.05; diltiazem 40%, p < 0.05 vs baseline) while decreasing systemic vascular resistance (nifedipine 41%, p < 0.05; diltiazem 28%, p NS vs baseline) 30 minutes after the dose. In contrast to single-dose diltiazem, the diltiazem-ibopamine subgroup exhibited an increased left ventricular filling pressure (122%, p < 0.05 vs baseline) and mean pulmonary artery pressure (43%, p < 0.05 vs baseline) at 30 minutes after the dose. One patient experienced a transient episode of chest pain associated with increased heart rate and blood pressure with diltiazem-ibopamine. CONCLUSION: Diltiazem and ibopamine should be coadministered with caution in patients with coronary artery disease and left ventricular dysfunction.