Induced atrial tachycardia after circumferential pulmonary vein isolation of paroxysmal atrial fibrillation: electrophysiological characteristics and impact of catheter ablation on the follow-up results.

INTRODUCTION: Atrial tachycardia (AT), including focal and reentrant AT, can occur after circumferential pulmonary vein isolation (CPVI). The aim of this study was to investigate the electrophysiological characteristics of induced AT and its clinical outcome. METHODS AND
RESULTS: In our series of 160 patients with paroxysmal atrial fibrillation (AF), 45 ATs were induced by high-current burst pacing after CPVI in 26 patients. All induced ATs were mapped using a three-dimensional (3D) mapping system. Noninducibility was the endpoint of the ablation of the AT. Gap-related AT was considered if the AT was related to the CPVI lesions. A 16-slice multidetector computed tomography scan was performed in all patients to correlate the anatomical structure with electroanatomical mapping. Thirty-five (78%) reentrant ATs and 10 (22%) focal ATs were identified. Of those, 34 were gap-related ATs (24 reentrant and 10 focal ATs). Reentrant AT had more gaps in the left atrial appendage ridge than did focal AT (39.6% vs 0%, P = 0.02). Focal AT had a higher incidence of gap in the PV carina compared with reentrant AT (80% vs 10%, P < 0.001). Reentrant ATs were mostly terminated during the ablation creating the mitral and roof lines with crossing of the gaps. During a mean follow-up of 21 +/- 8 months, only one patient (0.6%) with induced mitral reentry had a recurrent AT.
CONCLUSION: The location of the AT gap may be related with the complex anatomy of the LA. The induced ATs after CPVI can be eliminated by catheter ablation.