Coarse fibrillatory waves in atrial fibrillation predict success of electrical cardioversion

Background To determine whether the presence of “coarse” fibrillatory waves (Fw) seen on surface ECG s of patients with persistent atrial fibrillation ( AF ) predict maintenance of sinus rhythm ( SR ) at 6 weeks after electrical cardioversion ( ECV ). Methods Preprocedure ECG s from 94 consecutive patients with persistent AF scheduled to undergo ECV at a single centre were classified as having coarse Fw (≥0.1 mV) or fine Fw (<0.1 mV) in leads II or V 1 . The primary outcome was ECG rhythm at 6‐week clinical follow‐up. Demographic and echocardiographic data were also collected. Results Thirty‐two patient ECG s (34%) had coarse Fw on baseline ECG in either or both leads II or V 1 with no significant differences in baseline demographics compared to those patients with fine Fw. At 6 weeks post‐ ECV , in the coarse Fw group 72% of patients maintained SR vs. 42% in the fine Fw group (χ 2 , p  =   .006) with the odds ratio ( OR ) of maintaining SR at 6 weeks in the presence of coarse Fw being 3.5 (95% CI : 1.4–8.9, p  =   .007). Across the overall study population, there were no other significant univariate predictors of SR at 6 weeks post‐ ECV . Conclusion Classifying persistent AF using the maximal Fw amplitude on a surface ECG is a simple and reproducible method of predicting medium‐term success of ECV , independent of traditional risk factors.