Catheter Ablation -> Atrial Fibrillation & Atrial Flutter: -> Ablation Techniques D-PO02 - Poster Session II (ID 47) Poster

D-PO02-189 - Minimizing Posterior Wall Ablation During Single Ring Isolation For Atrial Fibrillation: A Case Series (ID 246)


Background: Atrial fibrillation (AF) ablation usually requires radiofrequency energy delivery to the posterior left atrium (LA), where the esophagus may be vulnerable to collateral thermal injury. A single ring technique to isolate the pulmonary veins and posterior LA en bloc can potentially minimize ablation to the posterior LA.
Methods: We describe 15 cases (63±11 years, 67% male 73%, paroxysmal AF, left atrial volume 77±26 mL) where a single ring technique was used to isolate the pulmonary veins and posterior left atrium with minimal or no ablation to the posterior wall itself. Single ring isolation was performed employing a technique that involved meticulous ablation anterior to the veins and along the roof, with completion of the inferior line last. Electroanatomic mapping software that facilitated automated data collection was used to objectively quantify ablation characteristics including the size of gaps in the inferior line (Figure 1).
Results: Gaps in the inferior line ranged from 16 to 35mm in length (median 22mm). Median ablation time to the posterior LA was 64 seconds (range 15 to 94 seconds) and the maximum power applied never exceeded 35 watts. After 12 months, 12 patients (80%) remained free from atrial arrhythmia and in one patient who underwent a redo procedure, ablation to a single spot in the mid posterior wall re-isolated the entire posterior LA.
Conclusion: In some instances, SRI of the posterior LA can be achieved with large gaps in the inferior line, minimizing ablation to the posterior LA. This may be the result of anatomic conduction block that occurs due to abrupt changes in myofiber orientation, thereby providing a physiologic basis for AF ablation.