P-wave parameters and clinical predictors of postoperative atrial fibrillation following coronary artery bypass graft surgery

Background Postoperative atrial fibrillation (POAF) is a common complication after coronary artery bypass grafting (CABG), affecting 20% to 40% of patients, and is associated with adverse outcomes and increased healthcare resource use. Although several preoperative ECG markers have been proposed, clinically practical prediction of POAF remains limited. Purpose To assess whether preoperative P-wave parameters, alongside clinical characteristics, can identify patients at increased risk of POAF after isolated CABG. Method We retrospectively analysed consecutive patients undergoing isolated CABG between January 2018 and December 2023. Preoperative 12-lead ECGs in sinus rhythm recorded within 30 days before surgery were analysed in patients without a history of atrial fibrillation (n=472). P-wave duration, amplitude, axis and dispersion were extracted automatically, and P-wave area, PR interval, P-wave terminal force in V1 (PTFV1) and interatrial block (IAB) were derived. Clinical variables (age, sex, BMI, hypertension, diabetes, and left ventricular function) were obtained from the Swedish National Registry for Cardiac Surgery (SWEDEHEART). The primary endpoint was POAF (≥30s episode) confirmed by telemetry/ECG during index hospitalisation. A multivariable logistic regression model was developed using preoperative and clinical variables. Results POAF occurred in 171/472 (36%) patients (Table 1). Patients with POAF were older (69 ± 7 vs 65 ± 9 years; p<0.001) and more often had hypertension (85% vs 78%; p=0.044). Compared with patients who remained in sinus rhythm, those with POAF had longer P-wave duration (p=0.048), lower P-wave amplitude (p=0.002), less negative PTFV1 (p=0.039), and higher prevalence of IAB (p=0.008). The multivariable model combining clinical variables and P-wave parameters showed modest discrimination, C-index 0.64 (Figure 1). Predicted-risk stratification showed a marked gradient in observed event rates, with POAF increasing from 12% in the lowest to 63% in the highest predicted-risk quartile, and overall close agreement between predicted and observed risks across quartiles. Conclusion POAF remains a common complication following CABG. Preoperative P-wave parameters combined with clinical variables may support risk stratification by identifying patients at higher risk, despite modest discrimination. The clinically meaningful gradient across predicted-risk strata supports potential utility for targeted preventive interventions. External validation and prospective evaluation of model-guided preventive strategies are warranted.TableFigure