Beat-to-beat variation of P-wave morphology immediately after ablation of persistent atrial fibrillation correlates with long-term clinical outcome

Abstract Funding Acknowledgements Type of funding sources: None. Background P-wave morphology on surface ECG reflects the atrial electrical remodelling, and is regarded as a predictor of ablation outcome for atrial fibrillation (AF). Purpose We sought to investigate whether morphological characteristics of P-waves immediately after a wide circumferential isolation of pulmonary veins (WPVI) in persistent AF (peAF) correlate with long-term maintenance of sinus rhythm (SR). Methods 33 patients (63±10 y, sustained AF 11±7 months) underwent a de-novo WPVI. A second WPVI was performed in patients with recurrent AF in order to provide complete PV disconnection. We defined "success" as patients who remained in SR after one or two procedures, and "failure" otherwise. The average duration and amplitude of the P-waves, and the coefficient of variation (CoV = standard deviation/mean) of the beat-to-beat similarity between ≥30 successive P-waves per patient were computed on ECG lead II during SR after cardioversion. Panel A shows a group of successive P-waves synchronized with regard to their centers of gravity. The similarity between the shapes of two successive synchronized P-waves was assessed using the dynamic time warping distance. Panel B shows the time-evolution of beat-to-beat distance between the P-waves displayed in Panel A. Results Over a mean follow-up of 31±9 months, 21 patients remained free from AF off antiarrhythmics (success group), while 12 patients had AF recurrence after 2 WPVIs (failure group). The clinical characteristics (e.g. age, body mass index, left atrial volume or duration in sustained AF) were similar between groups (p>0.05). The success group displayed significantly lower beat-to-beat variability of P-wave morphology than that of the failure group (p<0.05, Panel C). No significant difference was found in P-wave duration and amplitude between the two groups (p>0.05, Panel D and E). Conclusion Low P-wave beat-to-beat morphological variability immediately after WPVI for persistent AF is associated with long-term maintenance of sinus rhythm.