P wave morphology during spontaneous and paced pulmonary vein activity: differences between patients with atrial...

P wave morphology (PWM) has been used to predict the location of ectopic foci responsible for triggering atrial fibrillation (AF). With bi-atrial mapping, this study examined PWM during spontaneous ectopy and during pulmonary vein (PV) pacing, comparing the results with published algorithms in 40 AF patients and 15 controls. PWM during PV pacing is similar to spontaneous ectopy, if performed at similar coupling intervals. PWM during ectopic activity from the PVs is affected by cycle length and the presence of underlying atrial electrical and structural abnormalities. Changes in PWM during decremental pacing were observed in 5% of controls but in over 25% of persistent AF patients. The algorithms are accurate in over 90% of controls and paroxysmal AF patients with normal atria, but less than 60% in those with persistent AF or electrical or structural atrial abnormalities. The accuracy of non-invasive localization of arrhythmogenic PV is limited.