Effect of right atrial pacing, intravenous amiodarone and beta blockers for suppression of atrial fibrillation after coronary artery bypass surgery: a pilot study

Abstract

Objective: This pilot study aimed to compare right atrial pacing, intravenous amiodarone and oral beta-blockers in the prevention, time to onset, duration and effect on hospital stay of postoperative atrial fibrillation (AF) after coronary artery bypass graft surgery (CABG) at our center.

Background: AF is the most common arrhythmic complication after CABG and is related to increased morbidity, length of hospital stay and costs. Trials with different drugs and other therapeutic modalities including beta-blockers, intravenous amiodarone and override suppression of automatic atrial foci by atrial pacing have shown partial success as preventive measures. However, a comparison between those three interventions has not been reported.

Methods: Thirty-six consecutive patients that underwent CABG at our institution were randomly assigned to atrial pacing (18 patients) and intravenous amiodarone (18 patients) after baseline clinical, electrocardiographic and hemodynamic assessment. All patients received concomitant oral metoprolol or atenolol right after extubation. Thirty-three patients who had CABG at our center in the previous two months and that only received beta-blockers during their perioperative period served as a control group.

Results: The majority of baseline clinical and hemodynamic characteristics were similar in all groups. Only one patient (5.6%) developed AF in the atrial pacing group versus five (27.8%) on amiodarone and six (18.2%) who only received beta-blockers. That finding, however, did not attain statistical significance (p > 0.05). After adjusting for potential confounders, the odds of occurrence of AF was 77% lower in atrial pacing patients (OR = 0.23; 95% CI: 0.02, 2.20; p = 0.09) and 2.36 times higher in those on amiodarone (95% CI: 0.55, 10.24; P = 0.053) when compared to patients which only received beta blockers. Since only one patient on right atrial pacing developed atrial fibrillation, the analysis of the median time to onset and median duration of atrial fibrillation was restricted to those assigned to amiodarone and those who only received beta-blockers showing no statistically significant differences (p > 0.05). Although no statistical significance was achieved, the median hospital stay was one-day shorter in the beta-blockers group. Most of the side effects were minor and resolved without sequelae.

Conclusion: This pilot study showed a trend in favor of atrial pacing versus intravenous amiodarone or beta-blockers in the prevention of postoperative AF after CABG in our center. Randomization of a larger patient sample would be required in order to ascertain the true value of the observed trend.