Prediction of atrial fibrillation recurrence after cardioversion by P wavesignal-averaged electrocardiography

The purpose of this report was to determine prospectively whether P wave si gnal-averaged electrocardiography (ECG) is useful for the prediction of rec urrences of atrial fibrillation after cardioversion. The P wave signal-aver aged ECG was recorded in 73 patients after successful cardioversion. Durati on of the filtered P wave and the root mean square voltages for the last 20 ms of the P wave were calculated. In addition to signal-averaged ECG P wav e analysis, all patients were evaluated by echocardiography. During 6 month s follow-up period recurrence of atrial fibrillation was observed in 31 (42 .5%) patients and in 42 (57.5%) patients sinus rhythm was maintained. There was no difference in gender, age, presence of organic heart disease, left atrial diameter, left ventricular ejection fraction, use of antiarrhythmic drug, and duration of atrial fibrillation (P>0.05). The filtered P-wave dur ation was longer and the root mean square voltages for the last 20 ms of th e P wave was lower in patients with recurrence of atrial fibrillation than in patients who maintained sinus rhythm (138.3+/-12.5 ms vs. 112.4+/-11.8 m s, P=0.001; 1.9+/-0.7 mu V vs. 2.5+/-0.6 mu V, P=0.001). A filtered P-wave duration greater than or equal to 128 ms associated with a root mean square voltage for the last 20 ms of the P wave greater than or equal to 2.1 mu V had a sensitivity of 70% and specificity of 76% for the detection of patie nts with recurrence of atrial fibrillation after successful cardioversion o f atrial fibrillation. We found that the likelihood of recurrence of atrial fibrillation after cardioversion was increased 4.31-fold (95% confidence i nterval 2.08-9.83) if these parameters were used. These results suggest tha t P wave signal-averaged ECG could be useful to identify patients at risk f or recurrence of atrial fibrillation after cardioversion. (C) 1999 Elsevier Science ireland Ltd. All rights reserved.