Background: Delayed interatrial conduction, manifested on the electrocardiogram as a P wave >or=110 ms (interatrial block, IAB), is highly prevalent and associated with atrial fibrillation (AF). It is correlated with P-terminal force (Ptf; product of the duration and amplitude of the negative terminal phase of the P wave in lead V1). Our purpose was to describe the modifications of the P-wave duration and Ptf after pulmonary vein antrum isolation (PVAI) in patients with paroxysmal AF.
Methods: PVAI was performed in 45 patients with paroxysmal AF, either with the cryoballoon technique (n = 15) or radiofrequency ablation (n = 30). Electrocardiograms were recorded before PVAI, 3 and 6 months after ablation.
Results: From the sample (median age 60 [53; 66] years; female 40%), median P-wave duration was 122 [114; 134] ms before PVAI and 116 [106; 124] ms at 3-month follow-up (P < 0.001). IAB was observed in 42 patients (93.3%) before ablation and in 31 patients (68.9%) at 3-month follow-up. Median Ptf was 0.047 [0.020; 0.068] before ablation and 0.013 [0.004; 0.025] at 3-month follow-up (P < 0.001). Twenty-six patients (57.8%) had a Ptf > 0.04 mV x ms before ablation and only one (2.2%) at 3-month follow-up. P-wave duration and Ptf were not significantly modified between 3- and 6-month follow-up.
Conclusion: The terminal part of the P wave is modified after PVAI, perhaps due to the loss of pulmonary vein antrum signals. P-wave duration and Ptf must be carefully interpreted after such a procedure. The prognostic value of these modifications should be evaluated.