Prolonged signal-averaged P wave duration after elective cardioversion increases the risk of recurrent atrial fibrillation.

Objective: To assess the risk of atrial fibrillation (AF) recurrence after elective cardioversion of AF in relation to the signal-averaged P wave duration (SAPWD), clinical characteristics of the patient, and the duration of the AF disease.

Design: We studied 131 consecutive patients (88 men, 43 women), median age 67 years (range 29-87 years), after elective cardioversion of AF into sinus rhythm. The SAPWD was measured on inclusion, and the follow-up period was 1 month. Recurrent AF within the first month after cardioversion was regarded as endpoint.

Results: AF recurred in 73 patients (56%). Multiple logistic regression analysis showed that prolonged SAPWD above 160 ms was the only significant risk factor for recurrent AF, OR=2.22 (95% CI 1.07-4.60), p=0.03. There was no significant effect of age, diagnosed hypertension, diagnosed congestive heart failure, dilated left atrium, or long duration of AF on the risk of AF relapse.

Conclusion: Prolonged SAPWD above 160 ms is a risk factor for recurrent AF after elective cardioversion of persistent AF.