Relationship between left atrial scar and P wave dispersion in patients undergoing atrial fibrillation catheter ablation

Background Left atrial scar is an important entity in the atrial fibrillation substrate. P wave dispersion (PWD) is an indicator of slow and inhomogeneous conduction in the atria. In this study, we aim to investigate the relation between PWD and left atrial scars identified by electroanatomical mapping. Methods Patients who had an electroanatomical map obtained during sinus rhythm as well as at least one electrocardiogram in sinus rhythm prior to the procedure were included in the study. Left atrial scar (defined as <0.5 mV) area was calculated on the electroanatomical map. Maximum and minimum P wave duration and PWD were compared between patients with and without left atrial scar. Results A total of 224 patients were enrolled in the study. Of them, 47.9% of the patients were female. On the electroanatomical map, left atrial scar was identified in 103 patients, and no scar was present in 121 patients. PWD was significantly increased in patients with left atrial scar when compared to the no-scar group (46 ms +/- 20 vs. 38 ms +/- 15, respectively, p < 0.001). Similarly, PWD was significantly increased in patients with moderate-to-severe scar, when compared to patients with mild scar (50 ms +/- 19 vs. 41 ms +/- 19, respectively, p = 0.026). PWD was found not to be a good predictor of left atrial scar with an AUC of 0.625 for scar vs. no scar. Conclusion PWD is significantly increased in patients with left atrial scar identified by electroanatomical mapping, however, the receiver operating characteristic analysis showed that PWD is not a good predictor of presence of left atrial scar.