Predictors of Late Atrial Fibrillation Recurrence After Cardiac Surgery

Background: Although postoperative atrial fibrillation (POAF) frequently occurs early after cardiac surgery, there is a paucity of data evaluating predictors and timing of late atrial fibrillation (AF) recurrence. Objectives: The authors sought to evaluate predictors of late AF recurrence in patients undergoing cardiac surgery. Methods: We retrospectively reviewed cardiac surgery patients from 2010 to 2018 with no preoperative diagnosis of AF or atrial flutter. We recorded incidence and timing of late AF recurrence, defined as occurring ≥12 months following surgery. Results: 1,031 patients were included (mean age at surgery 64 ± 12 years, 74% male). Early POAF was recorded in 445 patients (43%). POAF was usually transient, with total AF duration <48 hours in 72% and reversion to sinus rhythm at discharge in 91%. At 4.7 ± 2.4 years follow-up, late AF occurred in 139 patients (14%). Median time to AF recurrence was 4.4 years post-surgery (Q1-Q3: 2.6-6.2 years). Late AF was significantly more likely among patients with early POAF than those without (23% vs 6%; P < 0.001), with highest incidence (38%) in those with POAF duration >48 hours. In a multivariable analysis, early POAF duration >48 hours was a significant predictor of late AF recurrence (HR: 5.9). Surgery type and CHA₂DS₂-VASc score were not predictive of late AF events. Conclusions: Post-operative AF episodes of duration ≥48 hours predict recurrent AF episodes over long-term follow-up after cardiac surgery. Implications for arrhythmia surveillance and anticoagulation in patients with longer duration POAF episodes require further study.