The prediction of atrial fibrillation recurrence after electrical cardioversion with P wave signal averaged electrocardiogram

The recurrence of atrial fibrillation after cardioversion has a high incidence. In our study, P wave signal averaged ECG was performed one day after successful electrical cardioversion in order to evaluate the utility of this method to predict atrial fibrillation after cardioversion. Method A P wave triggered and bidirectional P wave signal averaged ECG was used among 49 patients (35 m/14 w) 24 hours after electrical cardioversion. The measurements were only managed in sinus rhythm. Each patient was followed up for at least 6 months and the mean follow-up was of 9.1 months. Results A recurrence of atrial fibrillation was observed in 23 patients (47%) after a mean of 9,2 days (range 2-92 days). There was no difference in organic heart disease or in the use of drugs. The filtered P wave duration (FPD) was longer significantly (136.2 +/- 20.1 vs 119.5 +/- 19.8 ms, p < 0.0001) and the root mean square voltage of the last 20 ms of the P wave (RMS 20) was lower (2.77 +/- 1.10 vs 4.17 +/- 1.43 muV, p < 0.0001) in patients with a recurrence of atrial fibrillation. A cut-off point (COP) of FPDgreater than or equal to126 ins and RMS 20 less than or equal to 3.1 muV achieved a specificity of 69%, a sensitivity of 74%, a positive predictive value of 68% and a negative predictive value of 75%. Conclusion The results of our study suggest that the recurrence of atrial fibrillation after electrical cardioversion can be detected by P wave signal averaged ECG. The occurrence of COP seems to be a high risk factor of the recurrence of atrial fibrillation. The predictive power of the method has to be examined by prospective investigations of a larger patient population and a longer follow-up.