Atrial tachycardia during ongoing atrial fibrillation ablation. - EnSite array analysis-.

BACKGROUND

Atrial tachycardia (AT) occurring during atrial fibrillation (AF) ablation is sometimes difficult to identify and eliminate. EnSite Array (EA) visualizes beat-to-beat virtual activation of AT. The aim of the present study was to characterize AT occurring during AF ablation during ongoing AF, using EA.

METHODS AND RESULTS

Among 90 patients with AF (paroxysmal, n=67; persistent, n=23) who underwent radiofrequency catheter ablation during ongoing AF, 33 (37%) had 46 ATs that developed during ablation, and 9 (10%) of these patients had 9 ATs that developed before ablation. AT was sustained in 39 and non-sustained in 7. Nineteen ATs resulted from a focal mechanism and 27 from macroreentry. The major AT foci were distributed in the pulmonary vein (n = 8) and left atrial roof (n = 3), and macroreentrant ATs mainly consisted of peri-mitral AT (n = 10), common atrial flutter (n = 10), and roof reentrant AT (n = 3). After EA-guided ablation of AT, 41 ATs in 28 patients (85%) were eventually rendered non-inducible. During 21 ± 8 months of follow-up, 30 of the 33 patients (91%) were free from AF/AT recurrence.

CONCLUSIONS

AT occurred in 37% of the patients during ongoing AF ablation, resulting from a focal or reentrant mechanism in diverse locations. Peri-mitral AT, common atrial flutter, and AT from the pulmonary vein were frequently observed. These ATs were eliminated by EA-guided radiofrequency ablation in most cases.