Late atrial tachycardia following pulmonary vein isolation: analysis of successful discrete ablation sites.

Background: The role of additional left atrial linear lesions performed during pulmonary vein isolation (PVI) to prevent atrial tachycardias (ATs) is not yet clear.

Objective: To analyse successful ablation sites of late-onset post-PVI AT, and to understand whether additional ablation lines at mitral isthmus and left atrium (LA) roof could have been useful in preventing these jatrogenic ATs.

Methods: From March, 2002 to August, 2008, 366 patients underwent PVI alone for drug-refractory atrial fibrillation (AF). Twenty-six (7.1%) of these patients developed late AT during follow-up, and were referred for ablation. Successful discrete ablation sites were analysed. In no patient the index AT was terminated by a linear lesion in mitral isthmus or LA roof.

Results: Twenty-seven ATs were mapped; mean CL was 261 ± 71.6 ms. In 3/26 patients (11.5%), mapping was unsuccessful, while 23/26 (88.5%) patients underwent a successful procedure (24 AT morphologies in 23 patients - 3/24 were mapped as mitral isthmus, and 1/24, as LA roof-dependent AT). Among the 24 successfully mapped ATs, 17/24 (70.8%) displayed a macroreentrant activation and the remaining 7/24 (29.1%), a focal pattern. Finally, in 22/26 (84.6%) patients, ATs were no more inducible. At a mean f/u of 22.4 ± 12.2 months, 23/26 (88.4%) patients remained AT-free (antiarrhythmic drugs prescribed in 5/26, 19.2% patients for AF prevention).

Conclusions: In our case series, less than one-fifth of late-onset post-PVI ATs were mapped as mitral isthmus- or LA roof-dependent circuits.