Vagal AF induction test (VAFIT): a new endpoint for optimizing atrial fibrillation ablation through cardioneuroablation.

INTRODUCTION

Currently, there is no reliable endpoint for the conclusion of atrial fibrillation (AF) ablation. Atrial burst pacing and/or isoproterenol challenge are poor diagnostic tools. A newly proposed vagal AF induction test (VAFIT) uses effective atrial refractory period measurement, simultaneously with extra-cardiac vagal stimulation (ECVS) to study AF inducibility pre- and post-ablation. This is a prospective study in patients submitted to radiofrequency catheter pulmonary vein isolation (PVI) plus cardioneuroablation (CNA) evaluating the VAFIT result before and at the end of the procedure with AF recurrence.

METHODS

Prospective study of 142 patients, 57.5 (48.9-70.2) years old, 71% males, with symptomatic AF (79.6% paroxysmal/20.4% persistent), left atrium diameter of 38.0 (35.0-41.2) mm, and left ventricular ejection fraction of 63.0 (62.0-68.2). VAFIT was considered positive or negative depending on whether AF induction occurred. It was performed at baseline and after PVI + CNA, with a single atrial extra stimulus during ECVS (5 s/50 Hz/1 V/kg up to 70 V/pulse width = 50 µs). Patients were followed for a median of 15.0 (7.0-20.0) months. The association of VAFIT-positive status at the end of the procedure with AF recurrence was investigated by univariate and multivariate Cox regression analysis.

RESULTS

Pre-ablation VAFIT was positive in all cases and became negative in 62.9% of patients. AF recurrence: 18.7% in VAFIT-positive and 5.6% in VAFIT-negative patients (p = 0.012). VAFIT-positivity was associated with AF recurrence (HR 4.56 (1.37-15.23, p = 0.014).

CONCLUSION

A VAFIT-positive status following PVI + CNA was strongly and independently associated with AF recurrence. VAFIT negative status reduced 4.5 times the post-ablation AF recurrence. It remains to be investigated in randomized studies whether achieving VAFIT-negativity at the end of the procedure, as demonstrated in this study, would lead to better clinical outcomes.