56-28: Can the Origin be Identified Using Pace Mapping in Patients with Non-sustained or Difficult-to-induce Focal Atrial Tachycardia?

Abstract

Introduction: Focal atrial tachycardia (FAT) is extremely difficult to map and ablate when it is infrequent and non-sustained or difficult to induce. The objective of this study is to evaluate the efficacy of P-wave pace mapping (PPM) in identifying the FAT origin. Methods and Results: The study included 7 patients with drug-refractory FAT who experienced daily multiple episodes before ablation and presented with difficult-to-induce non-sustained FAT and a distinct P-wave morphology during ablation. PPM was systematically performed in the areas of interest using 3-D mapping to match the P-wave morphology and paced intracardiac activation sequence recorded from multiple catheters. The anatomical FAT origins were the right pulmonary vein (PV) in 3 patients, mitral annulus, crista terminalis, tricuspid annulus, and right-sided PV via a posterior conduction of previous PV isolation (PVI). In all patients, pace mapping obtained best matched P-wave morphology on 12-lead ECG in ≥11/12 leads at the successful ablation site, and paced intracardiac activation sequence was identical to induced FAT. Focal ablation was delivered in 4 patients, including non-PV FAT in 3 and FAT in 1, via posterior gap along the previous right-sided PVI, and right-sided PVI was performed in the other 3 patients. No FAT was induced at the end of the procedure. All patients were free of arrhythmias without antiarrhythmic drugs during the 8.4 ± 5.6-month follow-up.