Abstract 15975: Atrial Fibrillation Triggers From Non-PV, Non-SVC Foci: Assessment of Incidence, Characteristics and Efficacy of Catheter Ablation in a Single Center, High Volume Series

Backgrounds: The electrical isolation of the thoracic veins to eliminate triggers of atrial fibrillation (AF) is the mainstay of catheter ablation (CA) for AF. AF is sometimes triggered by repetitive firings from the non-PV, non-SVC (nPVnSVC) foci, and their characteristics have not been fully elucidated. Purposes: To elucidate the incidence, characteristics and efficacy of CA of the nPVnSVC foci in AF patients (pts). Methods: Consecutive 1491 pts who received CA for AF (1080 males, age: 64±10 years, paroxysmal: 995, non-paroxysmal: 496) were included in this study. In index procedures, PV and SVC isolation were performed in all pts without subsequent provocation of nPVnSVC triggers. In repeat procedures, high dose isoproterenol (up to 400μg/hr) and boluses of adenosine triphosphate were given to provoke AF initiation by nPVnSVC triggers and focal ablation of all AF triggers was performed. Results: Among 2097 procedures in all 1491 pts, 58 AF triggers from nPVnSVC foci were provoked in 55 pts (3.7%; 30 paroxysmal and 25 non-paroxysmal AF pts) during 57 procedures (12 index and 45 repeat procedures). The pts with nPVnSVC triggers were significantly more likely to be females (42 vs 28%; P=0.03). The trigger foci were localized in the RA (20 foci; CS os in 8, crista terminalis in 7, IVC os in 3 and tricuspid annulus in 2), LA (24 foci; anterior (6), inferior (3) and posterior wall (3), roof in 3, mitral annulus in 3, Marshall vein in 5 and appendage in 1) and septum (14 foci; left (7) and right side (2) of fossa ovalis, high right septum in 4 and non-coronary cusp of the aortic sinus in 1). All AF triggers were eliminated in 46 pts (84%), while in the others they were not. During follow-up after the last procedure (284±218 days), recurrence-free survival was similar in those with and without nPVnSVC triggers (91 vs 95%; P=0.05), although mean procedure number was significantly larger in those with nPVnSVC triggers than in those without (2.1±0.6 vs 1.4±0.6 times/pt; P<0.0001). Conclusions: The nPVnSVC triggers were observed in 3.7% of all AF pts. The location of the triggers could be clustered to the several anatomical regions. Successful elimination of nPVnSVC triggers contributed to high post-ablation recurrence-free survival that was similar to that in those without nPVnSVC triggers.