Timing of β-Blocker Reintroduction and the Occurrence of Postoperative Atrial Fibrillation after Cardiac Surgery: A Prospective Cohort Study.

Background: For cardiac surgery patients under chronic beta-blocker therapy, guidelines recommend their early postoperative reintroduction to decrease the incidence of postoperative atrial fibrillation. The authors hypothesized that the timing of beta-blocker reintroduction affects their effectiveness on the incidence of postoperative atrial fibrillation. Methods: This multicenter prospective French cohort study included patients on beta-blockers (more than 30 days before surgery) in sinus rhythm without a pacemaker. The primary outcome, time sequence of beta-blocker reintroduction, was analyzed for 192 h after surgery. The secondary outcome, relationship between the occurrence of postoperative atrial fibrillation and timing of beta-blocker reintroduction, was analyzed based on pre- and intraoperative predictors (full and selected sets) according to landmark times (patients in whom atrial fibrillation occurred before a given landmark time were not analyzed). Results: Of 663 patients, beta-blockers were reintroduced for 532 (80%) but for only 261 (39%) patients in the first 48 h after surgery. Median duration before reintroduction was 49.5 h (95% CI, 48 to 51.5 h). Postoperative atrial fibrillation or death (N = 4) occurred in 290 (44%) patients. After performing a landmark analysis to take into account the timing of beta-blocker reintroduction, the adjusted odds ratios (95% CI) for predictor full and selected (increased age, history of paroxysmal atrial fibrillation, and duration of aortic cross clamping) sets for the occurrence of postoperative atrial fibrillation were: adjusted odds ratio (full) = 0.87 (0.58 to 1.32; P = 0.517) and adjusted odds ratio (selected) = 0.84 (0.58 to 1.21; P = 0.338) at 48 h; adjusted odds ratio (full) = 0.64 (0.39 to 1.05; P = 0.076) and adjusted odds ratio (selected) = 0.58 (0.38 to 0.89; P = 0.013) at 72 h; adjusted odds ratio (full) = 0.58 (0.31 to 1.07; P = 0.079) and adjusted odds ratio (selected) = 0.53 (0.31 to 0.91; P = 0.021) at 96 h. Conclusions: beta-Blockers were reintroduced early (after less than 48 h) in fewer than half of the cardiac surgery patients. Reintroduction decreased postoperative atrial fibrillation occurrence only at later time points and only in the predictor selected set model. These results are an incentive to optimize (timing, doses, or titration) beta-blocker reintroduction after cardiac surgery.