Abstract 1872: Beta Blocker (BB) Use Was Associated with Reduced Atrial Fibrillation (AF) and Flutter (AFL) in the Sudden Cardiac Death Heart Failure Trial (SCD-HeFT)
Background: AF in HF patients is associated with increased morbidity and mortality. Prior studies observed reduced rates of AF with BB use in the settings of myocardial infarction, cardiovascular surgery and after cardioversion. Limited data suggest that carvedilol may have additional antiarrhythmic effects over other BBs. The impact of BB use on the development of AF/AFL in the setting of HF has not been reported.
Methods: The relationship between BB use and AF/AFL was studied in the patients enrolled in SCD-HeFT. A multivariable Cox proportional hazards analysis controlling for all previously identified predictors of AF/AFL was used. Patients were classified as BB+ if they reported BB use >90% and BB- if <10% of the time they were enrolled in the trial. Patients with AF on the baseline ECG were excluded from the analysis. Analyses were performed to assess differential effects between carvedilol vs. other BBs and in ischemic vs. nonischemic etiology of HF.
Results: There were 1753 BB+ (57% carvedilol, 31% metoprolol, 12% other) and 372 BB- patients. The rates of AF/AFL were 15% for the BB+ and 27% for the BB- group over a median follow up of 45.5 months. On multivariable analysis BB+ vs. BB- was independently associated with a reduced risk of subsequent AF/AFL (HR [95% CI] =0.43 [0.33, 0.56], p=0.001). There was no difference between BB types (carvedilol vs. other BB), and no interaction between BB usage and ischemic vs. nonischemic etiology of HF.
Conclusions: BB use was associated with an independent and substantially lower risk of subsequent AF/AFL in the HF patients enrolled in SCD-HeFT. The effect was present in nonischemic and ischemic HF patients and regardless of which BB was used.