Despite the results of a large-scale trial, some experts questioned the use of beta-blockers for patients that suffered from heart failure and simultaneous AFib when in the presence of beta-adverse medications, like amiodarone.
Results from the largest randomized trial to date in patients with both heart failure and atrial fibrillation (AFib) support recommendations for using beta-blocker medications for heart failure with reduced ejection fraction (HFrEF), despite a recent meta-analysis questioning their use when there is concurrent AFib.
Julia Cadrin-Tourigny MD, Montreal Heart Institute, Université de Montréal, Quebec, Canada, and colleagues reported a significantly lower mortality rate in patients with heart failure receiving beta-blockers regardless of concurrent AFib, although without finding a corresponding reduction in the rate of hospitalization.
An accompanying editorial, by Jonathan Piccini MD and Larry Allen MD, noted: "atrial fibrillation and heart failure are two colliding epidemics." In attempting to reconcile the findings of the current study from the AF-CHF trial, and those of the previous meta-analysis from the Beta-Blockers Heart Failure Collaborative Group, Piccini and Allen concluded, "in short, one cannot.”
They do, however, concur with Cadrin-Tourigny and colleagues, in affirming the role of beta-blockers in this circumstance. "At present, we believe clinicians should initially default to prescribing evidence-based beta-blockers in all patients with HFrEF regardless of AFib status," they said.
One of the points of caution suggested by Piccini and Allen on interpreting results from the current trial, however, prompted a response by Cadrin-Tourigny and colleagues in a subsequent publication. It was indicated that the researchers had not accounted for the potential impact of beta-blockade effects of the calcium channel blocker, amiodarone (Norvasc, Pfizer), which had been used by a substantial portion of the study cohort.
Cadrin-Tourigny and colleagues replied that the beta-antagonism property of amiodarone had been recognized, and was factored in their propensity match score for patients receiving beta-blockade medications. "Accounting for amiodarone is, indeed, a critical issue considering that it was the drug of choice for patients randomized to rhythm control therapy and that it has ß-antagonism properties," Cadrin-Tourigny said.
The AF-CHF trial randomized 1,376 patients with AF and HFrEF to receive rhythm control treatment (n=694) or rate control treatment (n=682). In this substudy of the trial, the impact of beta-blockers on outcomes was assessed against the pattern or burden of AFib in propensity matched cohorts; with 426 on a beta-blocker medication and 229 without, and 42% of each group receiving amiodarone.
Cadrin-Tourigny and colleagues reported that the beta-blockers were associated with a 28% reduction in all-cause mortality and that this result persisted regardless of concurrent AFib, or whether the AFib was paroxysmal or persistent, long or short duration, or presenting a high or low burden.
The researchers suggested several possibilities for the divergence of their findings from those of the meta-analysis, including the meta-analysis having grouped a sizeable proportion of patients with nonpermanent AFib with those having no AFib.
The reason for not finding a reduction in hospitalization with beta-blocker medication to correspond to the reduction in mortality was unclear, and the researchers speculated that the beneficial effects of beta-blockers may have been countered, in part, by a trend toward a higher rate of hospitalization with AFib.
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