Coarse fibrillatory waves in atrial fibrillation predict success of electrical cardioversion

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).

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.

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.

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.