Risk factors for bradycardia requiring pacemaker implantation in patients with atrial fibrillation.

Symptomatic bradycardia may complicate atrial fibrillation (AF) and necessitate a permanent pacemaker. Identifying patients at increased risk for symptomatic bradycardia may reduce associated morbidities and health care costs. The aim of this study was to investigate predictors for developing bradycardia requiring a permanent pacemaker in patients with AF. The records of all patients treated for AF or atrial flutter in an academic hospital's emergency department from August 1, 2005, to July 31, 2008, were reviewed. Survival and the presence of a pacemaker as of November 1, 2011, were determined. Cases were defined as patients with pacemakers placed for bradycardia after their AF diagnoses. Patients without pacemakers who were followed constituted the control group. Variables for the logistic regression analysis were identified a priori. A post hoc model was fit adjusting for AF type and atrioventricular nodal blocker use. Of the 362 patients in the cohort, 119 cases had permanent pacemakers implanted for bradycardia after AF diagnosis, and 243 controls were alive without pacemakers. The median follow-up time was 4.5 years (interquartile range 3.8 to 5.4). Odds ratios were determined for age at the time of AF diagnosis (1.02, 95% confidence interval [CI] 1 to 1.04), female gender (1.58, 95% CI 0.95 to 2.63), previous heart failure (2.72, 95% CI 1.47 to 5.01), and African American race (0.33, 95% CI 0.12 to 0.94). The post hoc model identified permanent AF (odds ratio 2.99, 95% CI 1.61 to 5.57) and atrioventricular nodal blocker use (odds ratio 1.43, 95% CI 0.85 to 2.4). In conclusion, in patients with AF, heart failure and permanent AF each nearly triple the odds of developing bradycardia requiring a permanent pacemaker; although not statistically significant, our results suggest that women are more likely and African Americans less likely to develop bradycardia requiring pacemaker implantation.