Association between rhythm control strategy and clinical outcomes in postoperative atrial fibrillation after coronary artery bypass grafting: a retrospective cohort study

The optimal management strategy for postoperative atrial fibrillation (POAF) following coronary artery bypass grafting (CABG) remains debated. While rhythm control aims to restore sinus rhythm, its impact on clinical resource utilization and long-term outcomes remains unclear. This study aimed to investigate the association between an initial rhythm control strategy (as an escalation to rate control) and clinical outcomes compared to rate control alone. This retrospective cohort study identified 663 adult patients who developed POAF after isolated CABG from the MIMIC-IV database. We used two statistical approaches to control for confounding: a primary analysis on a 1:1 propensity score-matched (PSM) cohort and a sensitivity analysis using inverse probability of treatment weighting (IPTW) on the entire cohort. The primary outcome was sinus rhythm (SR) conversion within 24 h. Secondary outcomes included length of ICU stay, acute kidney injury (AKI), and long-term mortality. The rhythm control strategy was associated with a higher 24-hour SR conversion rate compared to rate control (PSM cohort: 71.7% vs. 32.3%; OR, 2.65; P = 0.010). However, patients in the rhythm control group had a significantly longer ICU length of stay (median 3.42 vs. 3.08 days; P = 0.026). No significant differences were found in AKI incidence or long-term mortality. Subgroup analysis indicated that the benefit of SR conversion was attenuated in patients with diabetes (P for interaction < 0.05). Findings were consistent in the IPTW sensitivity analysis. Although effective for early rhythm restoration, an initial rhythm control strategy is associated with longer ICU stays and no survival benefit compared to rate control.