Novel electrocardiographic classification for stroke prediction in atrial fibrillation patients undergoing cardioversion

Background Abnormal conduction, structure and function of the atrial myocardium predispose to atrial fibrillation (AF) and stroke. Usefulness of electrocardiographic (ECG) indices in predicting stroke or systemic embolism (SSE) in patients undergoing cardioversion for AF remains unknown, especially in those at low estimated risk. Objective To systematically evaluate the performance of various P-wave abnormalities (PWA) in predicting SSE 30 days after cardioversion (derivation cohort) and in the long-term (validation cohort). Methods ECGs (n=1773) of AF patients undergoing an acute cardioversion were manually reviewed. The 30-day post-cardioversion data was used to derive a composite PWA variable. The ECG findings were validated using the long-term follow-up of patients with no anticoagulation. ECGs of 27 CAREBANK study patients with right atrial appendage biopsies were further analyzed for histopathological validation. Results During data derivation, the best performance was found using a combination of prolonged P-wave (≥180ms), deflected P-wave morphology in lead II, biphasic P-waves in inferior leads or increased P-terminal force (≥80mm*ms) as markers for extensive PWA. In the validation cohort 219/874 (25.1%) had extensive PWA. During a median follow-up of 4.9 years, there were 51 (5.8%) SSE in total. In a competing risk model PWA predicted SSE (aHR 2.1 per category, 95%CI 1.4-3.1, p<0.001). Area under the curve for SSE at 3 years were 0.77, 0.79 and 0.86 for PWA, CHA2DS2-VASc score or their combination, respectively. Histologically, extensive PWA was associated with interstitial fibrosis (p=0.033). Conclusion Novel electrocardiographic PWA classification provided additional prognostic insight in AF patients.