Motivation: When a patient is admitted with acute heart failure and laboring to breathe, I often debate whether or not to continue the home metoprolol. In chronic heart failure, I understand the bit about beta-blockade having protective effects. But, acutely, beta-blockers decrease heart inotropy resulting in decreased cardiac output and elevated left ventricular filling pressures - effects that are not helpful in acute heart failure. Like so many things in cardiology, it turns out that there has been a randomized trial with a nice acronym (B-CONVINCED) that examines this issue.
Paper: "B-CONVINCED: Beta-blocker CONtinuation Vs. INterruption in patients with Congestive heart failue hospitalizED for a decompensation episode." Jondeau, G. et. al. European Heart Journal (2009) 30: 2186-2192.
Methods: Randomized, controlled, open-labelled trial conducted in 36 centres in France. Eligible patients were older than 18 on chronic beta-blocker therapy hospitalized for acute heart failure (including pulmonary edema) with left ventricular ejection fraction less than 40%. Patients were excluded if found to have STEMI, bradycardia, or second-third degree heart block. Patients who were initially judged to need dobutamine therapy were also excluded. Intervention was continuation of home-dose beta-blocker therapy or discontinuation of beta-blocker for at least 3 days. Primary endpoint was the general health and dyspnea at 3 days of hospitalization.
Results:
Subjects: Analysis was performed in 147 patients (69 on BB therapy and 78 without BB). There were no significant differences between groups including age, etiology (ischemic vs non-ischemic), ejection fraction, prevalence of atrial fibrillation, or home CHF treatment regimen. The most common cause for acute exacerbation was non-adherence to therapy. The beta-blockers most commonly used were bisoprolol (beta-1 blocker) 70%, carvedilol 11%, and atenolol 10%. In the group on beta-blocker therapy, beta-blockers were stopped in four patients (three needed dobutamine and one had bronchospasm).
Hospital Courses: There were no significant differences in clinical features of heart failure (dyspnea, pulmonary rales, lower extremity edema, JVD, hepatomegaly) on the first 8 days of hospitalization (including day 3) between the two groups. Patients without BB had higher heart rates :) There were no differences in blood pressure during the course of hospitalization in the two groups. No differences were observed in BNP levels either. One death occurred in the BB group while two deaths occurred in the BB stopped group (difference not significant).
Long-term Follow-up: At 3 months, death rate and re-hospitalization rate were similar in both groups. After 3 months, patients who were continued on beta-blockers were more likely to be receiving beta-blockers (90%) than those who had beta-blockers stopped (76%, p=0.04).
Discussion: This paper shows that even during acute heart failure exacerbations, beta-blockers can be safely continued without adversely affecting rate of recovery. On the other side of the fence, one can also say that this paper shows beta-blockers can be discontinued during hospitalization without affecting rate of recovery. Between these two varying viewpoints, I would favor continuing beta-blockers since beta-blockers decrease myocardial ischemia and have proven anti-arrhythmic effect. Also, as shown in the paper, once beta-blockers are discontinued upon hospitalization, the risk of beta-blockers not being restarted upon discharge increases.
While the paper demonstrates non-inferiority of continuing beta-blockers during acute heart failure, this trial has some important limitations. First, the study was underpowered to detect potential benefit of beta-blockers in preventing arrhythmias during heart failure. That part of the benefit of beta-blockers in acute heart failure remains speculative. Also, in the study, the beta-blocker dosage was not standardized. It is unclear if beta-blocker titrated to, for example, heart rate is beneficial in one dosage but detrimental at higher doses.
Paper: "B-CONVINCED: Beta-blocker CONtinuation Vs. INterruption in patients with Congestive heart failue hospitalizED for a decompensation episode." Jondeau, G. et. al. European Heart Journal (2009) 30: 2186-2192.
Methods: Randomized, controlled, open-labelled trial conducted in 36 centres in France. Eligible patients were older than 18 on chronic beta-blocker therapy hospitalized for acute heart failure (including pulmonary edema) with left ventricular ejection fraction less than 40%. Patients were excluded if found to have STEMI, bradycardia, or second-third degree heart block. Patients who were initially judged to need dobutamine therapy were also excluded. Intervention was continuation of home-dose beta-blocker therapy or discontinuation of beta-blocker for at least 3 days. Primary endpoint was the general health and dyspnea at 3 days of hospitalization.
Results:
Subjects: Analysis was performed in 147 patients (69 on BB therapy and 78 without BB). There were no significant differences between groups including age, etiology (ischemic vs non-ischemic), ejection fraction, prevalence of atrial fibrillation, or home CHF treatment regimen. The most common cause for acute exacerbation was non-adherence to therapy. The beta-blockers most commonly used were bisoprolol (beta-1 blocker) 70%, carvedilol 11%, and atenolol 10%. In the group on beta-blocker therapy, beta-blockers were stopped in four patients (three needed dobutamine and one had bronchospasm).
Hospital Courses: There were no significant differences in clinical features of heart failure (dyspnea, pulmonary rales, lower extremity edema, JVD, hepatomegaly) on the first 8 days of hospitalization (including day 3) between the two groups. Patients without BB had higher heart rates :) There were no differences in blood pressure during the course of hospitalization in the two groups. No differences were observed in BNP levels either. One death occurred in the BB group while two deaths occurred in the BB stopped group (difference not significant).
Long-term Follow-up: At 3 months, death rate and re-hospitalization rate were similar in both groups. After 3 months, patients who were continued on beta-blockers were more likely to be receiving beta-blockers (90%) than those who had beta-blockers stopped (76%, p=0.04).
Discussion: This paper shows that even during acute heart failure exacerbations, beta-blockers can be safely continued without adversely affecting rate of recovery. On the other side of the fence, one can also say that this paper shows beta-blockers can be discontinued during hospitalization without affecting rate of recovery. Between these two varying viewpoints, I would favor continuing beta-blockers since beta-blockers decrease myocardial ischemia and have proven anti-arrhythmic effect. Also, as shown in the paper, once beta-blockers are discontinued upon hospitalization, the risk of beta-blockers not being restarted upon discharge increases.
While the paper demonstrates non-inferiority of continuing beta-blockers during acute heart failure, this trial has some important limitations. First, the study was underpowered to detect potential benefit of beta-blockers in preventing arrhythmias during heart failure. That part of the benefit of beta-blockers in acute heart failure remains speculative. Also, in the study, the beta-blocker dosage was not standardized. It is unclear if beta-blocker titrated to, for example, heart rate is beneficial in one dosage but detrimental at higher doses.
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