Characterization of Changes in P-Wave VCG Loops Following Pulmonary-Vein Isolation

Abstract

Atrial fibrillation is the most common type of cardiac arrhythmia in clinical practice. Currently, catheter ablation for pulmonary-vein isolation is a well-established treatment for maintaining sinus rhythm when antiarrhythmic drugs do not succeed. Unfortunately, arrhythmia recurrence after catheter ablation remains common, with estimated rates of up to 45%. A better understanding of factors leading to atrial-fibrillation recurrence is needed. Hence, the aim of this study is to characterize changes in the atrial propagation pattern following pulmonary-vein isolation, and investigate the relation between such characteristics and atrial-fibrillation recurrence. Fifty patients with paroxysmal atrial fibrillation who had undergone catheter ablation were included in this study. Time-segment and vectorcardiogram-loop-morphology analyses were applied to characterize P waves extracted from 1 min long 12-lead electrocardiogram segments before and after the procedure, respectively. Results showed that P-wave vectorcardiogram loops were significantly less round and more planar, P waves and PR intervals were significantly shorter, and heart rate was significantly higher after the procedure. Differences were larger for patients who did not have arrhythmia recurrences at 2 years of follow-up; for these patients, the pre- and postprocedure P waves could be identified with 84% accuracy.

Variation of P-wave indices in paroxysmal atrial fibrillation patients before and after catheter ablation

“…Not only P-waves dispersion of duration appeared to be reduced after the procedure, but also the amplitude dispersion, which is reflected in parameters AD and ADI. This decrease presented in our preliminary study [51] is also related with the significant increment of cross-correlation (measured as ρ) between P-waves, which can be explained by less amount of fragmentation and variability associated with the absence of atrial arrhythmias substrate [49].…”

“…On the other hand, in our data set P-wave mean duration did not significantly differ, despite the fact that it was mostly shorter once the pulmonary veins were completely isolated when individually comparing the paired data of each subject. Nevertheless, for a smaller cohort of the patients involved in this study [51], we can observe that P wave duration was significantly shorter after pulmonary vein isolation was completed. This result agrees with previous studies which have found that patients who are likely to develop AF have longer P-waves [21,26,28].…”