Clinical study
Beta-blocker therapy influences the hemodynamic response to inotropic agents in patients with heart failure: A randomized comparison of dobutamine and enoximone before and after chronic treatment with metoprolol or carvedilol

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Abstract

Objectives

We compared the hemodynamic effects of dobutamine and enoximone administration before and after long-term beta-blocker therapy with metoprolol or carvedilol in patients with chronic heart failure (HF).

Background

Patients with HF on beta-blocker therapy may need hemodynamic support with inotropic agents, and the hemodynamic response may be influenced by both the inotropic agent and the beta-blocker used.

Methods

The hemodynamic effects of dobutamine (5 to 20 μg/kg/min intravenously) and enoximone (0.5 to 2 mg/kg intravenously) were assessed by pulmonary artery catheterization in 29 patients with chronic HF before and after 9 to 12 months of treatment with metoprolol or carvedilol at standard target maintenance oral doses. Hemodynamic studies were performed after ≥12 h of wash-out from all cardiovascular medications, except the beta-blockers that were administered 3 h before the second study.

Results

Compared with before beta-blocker therapy, metoprolol treatment decreased the magnitude of mean pulmonary artery pressure (PAP) and pulmonary wedge pressure (PWP) decline during dobutamine infusion and increased the cardiac index (CI) and stroke volume index (SVI) response to enoximone administration, without any effect on other hemodynamic parameters. Carvedilol treatment abolished the increase in heart rate, SVI, and CI and caused a rise, rather than a decline, in PAP, PWP, systemic vascular resistance, and pulmonary vascular resistance during dobutamine infusion. The hemodynamic response to enoximone, however, was maintained or enhanced in the presence of carvedilol.

Conclusions

In contrast with its effects on enoximone, carvedilol and, to a lesser extent, metoprolol treatment may significantly inhibit the favorable hemodynamic response to dobutamine. No such beta-blocker–related attenuation of hemodynamic effects occurs with enoximone.

Abbreviations

ACEI
angiotensin-converting enzyme inhibitor
ANOVA
analysis of variance
CI
cardiac index
HF
heart failure
HR
heart rate
LVEF
left ventricular ejection fraction
MAP
mean arterial pressure
NYHA
New York Heart Association
PAP
mean pulmonary artery pressure
PDE
phosphodiesterase
PVR
pulmonary vascular resistance
PWP
pulmonary wedge pressure
SVI
stroke volume index
SVR
systemic vascular resistance

Cited by (0)

This study was partially supported by CARIPLO funds from “Centro per lo Studio del Trattamento dello Scompenso Cardiaco” of the University of Brescia.