New-onset post-operative AF recurrence after cardiac surgery detected by implantable loop recorders: A systematic review and Meta-analysis

Background Atrial fibrillation (AF) is one of the most common complications after cardiac surgery. New-onset post-operative AF may signal an elevated risk of AF and associated outcomes in long-term follow-up. We aimed to estimate the rate of AF recurrence as detected by an implantable loop recorder (ILR) in patients experiencing post-operative AF within 30 days after cardiac surgery. Methods We searched MEDLINE, Embase and Cochrane CENTRAL to April 2023 for studies of adults who did not have known AF, experienced new-onset AF within 30 days of cardiac surgery and received an ILR. We pooled individual participant data on timing of AF recurrence using a random-effects model with a frailty model applied to a Cox proportional hazard analysis. Results From 8671 citations, 8 single-centre prospective cohort studies met eligibility criteria.Data were available from 185 participants in 7 studies, with a median follow-up of 1.7 (IQR: 1.3–2.8) years. All included studies were at a low risk of bias. Pooled AF recurrence rates following 30 post-operative days were 17.8% (95% CI 11.9%–23.2%) at 3 months, 24.4% (17.7%–30.6%) at 6 months, 30.1% (22.8%–36.7%) at 12 months and 35.3% (27.6%–42.2%) at 18 months. Conclusions In patients who experience new-onset post-operative AF after cardiac surgery, recurrence lasting at least 30 s occurs in approximately 1 in 3 in the first year after surgery. The optimal frequency and modality to use for monitoring for AF recurrence in this population remain uncertain.