P-Wave Duration in a 12-lead electrogram used as a predictor of recurrence in atrial fibrillation cryoballoon ablation
Authors: Spinthakis N , Adarsh Sivasundaram AS , Rory Rule RR , Guy Haywood GH 
Published: July 2021

Abstract

Funding Acknowledgements
Type of funding sources: None.

Background
There is growing evidence that p-wave duration (PWD) is associated with the extent of left atrial scarring and may be a potential predictor of AF recurrence following ablation. Previous studies have used amplified techniques to measure this, however its predictive role using only a 12-lead surface electrogram (ECG) is not known. Patients with paroxysmal atrial fibrillation (AF) are often treated (75% clinical success) with a single cryoballoon catheter ablation procedure. In contrast, in patients with long persistent AF, cryoballoon ablation often yields lower success rates resulting in multiple ablations.

Purpose
We aimed to investigate whether PWD in a baseline 12-lead ECG is associated with AF recurrence post acutely successful PVI cryoablation.

Methods
In this retrospective single center study we assessed (n = 104) consecutive patients undergoing cryoablation for AF between 2016 and 2020. 12-lead surface ECGs along with demographic, echocardiographic and procedural data were extracted from patients’ case notes at the time they were in sinus rhythm prior to AF ablation, including following direct current cardioversion (DCCV) in patients with persistent AF. Measurements of the PWD were taken by two independent assessors blinded to the results in lead II or V1 at standard settings of 25mm/sec speed and 1mV per 10mm voltage. The outcome of interest was documented recurrence of AF after acutely successful PVI ablation at a median follow up of 16 months. Predictive ability of PWD for the primary outcome was tested using the ROC curve analysis and c-statistics.

Results
AF ablation was successful in 60% of the patients with greater effect in paroxysmal AF (78%, n = 36 paroxysmal AF ; 48% n = 26 long-persistent AF). The pre-procedural PWD was significantly longer among patients with recurrence of AF compared to the ones that remained in sinus rhythm (145 ± 14 ms vs 92 ± 26 ms, p &lt; 0.00001 ; paroxysmal AF p &lt; 0.00001 ; long-persistent AF p &lt; 0.0001). There was no difference in the baseline characteristics between the two groups. A PWD ≥ 130ms was strongly predictive of AF recurrence (c-statistic 0.94, 95% CI 0.90 – 0.98 ; p &lt;0.0001) with a positive predictive value of 88.5% and a negative predictive value of 87.5%. Patients with a PWD ≥130ms had a 2.4-fold risk of AF recurrence compared to those with PWD &lt; 130 at baseline (HR 2.38 , 95% CI 1.605 – 3.160 ; p &lt; 0.0001) (figure 1). There was no significant intra-operator variability in the measurements of the PWD (Bias 1.39 ± 13.9, 95% CI -0.42 – 4.79 ; p = NS).

Conclusion
In patients undergoing pulmonary vein isolation cryoablation, a baseline 12-lead ECG appears to be useful in predicting AF recurrence. Patients with PWD ≥130ms have a 2.4-fold risk of AF recurrence compared with patients with lower PWD. If confirmed in larger data sets, this simple technique may be a useful additional tool for clinical decision-making in the selection of patients for AF ablation. Abstract Figure 1