Use of noninvasive electrocardiographic imaging to predict ablation success in persistent atrial fibrillation

Introduction

In patients with persistent Atrial Fibrillation (AF), recurrence rates after a first ablation procedure remain high (25-50%) highlighting the need for pre-procedural markers that can predict ablation success. Noninvasive electrocardiographic imaging (ECGI) has emerged as a powerful technology to characterize the atrial substrate.

Objective

To identify noninvasive mapping parameters that can predict recurrence after catheter ablation in patients with persistent AF.

Methods

A total of 44 patients referred for the first catheter ablation procedure of persistent atrial fibrillation were prospectively studied. All procedures included pulmonary vein isolation (PVI) and posterior wall ablation with pulsed field ablation. During the procedure, ECGI was performed using a 128-electrode vest placed on the patient’s torso. For each patient, 5 minutes of baseline atrial fibrillation were analyzed.

The atria were segmented into 12 regions (7 in LA and 5 in RA). To characterize atrial fibrillation dynamics, stability maps were computed to identify the atrial regions exhibiting the fastest activation over time. Stability was quantified for each mapping point as the percentage of time its dominant frequency remained above the 90th percentile of all atrial dominant frequencies at each time point. Atrial regions with stability values above the 98th percentile were defined as dominant regions.

Patients were followed at 6 and 12 months using a 30-day Holter monitoring. Those with documented AF recurrence before the follow-up visit were not re-monitored with Holter.

Results

During follow-up, 19 patients (43.2%) experienced AF recurrence. The mean time to recurrence was 126.28 ± 91.49 days.

No statistically significant differences were found between patients with and without recurrence in demographic or clinical variables.

In the univariate analysis, patients with recurrence showed higher RA maximum stability than those without (37.21% vs 30.57%, p = 0.017). Moreover, those whose baseline dominant region was confined exclusively to the left atrium (LA) showed a lower recurrence rate (29.6% vs 64.7%, p = 0.022, Chi-square test).

A Cox proportional hazards model was subsequently performed to evaluate recurrence-free survival. In the forward stepwise multivariate model, the variables that remained significant predictors of recurrence were acute AF termination during the procedure, time since AF diagnosis, and maximum stability in the right atrium.

Conclusions

This study suggests that a right atrial substrate is determinant of ablation failure in persistent AF, since patients that recurred had higher Stability in the RA, and having dominant regions in RA was a risk factor for recurrence. Therefore, pre-procedural noninvasive mapping could be essential to stratify patients. Those with LA-only drivers might be suitable for standard ablation whereas those with RA involvement may be candidates to a more extensive approach, potentially involving Right Atrium.Right Atrium variablesMap example with and without recurrence