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 ECGs of patients with persistent atrial fibrillation (AF) predict maintenance of sinus rhythm (SR) at 6 weeks after electrical cardioversion (ECV). METHODS: Preprocedure ECGs 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 V1 . The primary outcome was ECG rhythm at 6-week clinical follow-up. Demographic and echocardiographic data were also collected. RESULTS: Thirty-two patient ECGs (34%) had coarse Fw on baseline ECG in either or both leads II or V1 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 (χ2 , 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.