Veins, Box, and Beyond: Are Two Atrial Fibrillation Ablation Energy Sources Better than One?

Objectives: While pulmonary vein isolation (PVI) forms the basis of atrial fibrillation (AF) ablation, it leaves many patients undertreated. Additional lines on both atria are required, but gaps and nontransmurality limit restoration of sinus rhythm (SR). We tested if the combination of cryo- and radiofrequency (RF) energy (dual) is more efficient than RF alone to treat AF.

Methods: Seventeen patients (10 paroxysmal and 7 long persistent) underwent total thoracoscopic beating heart ablation (TTA). Lesion sets included PVI, left atrial appendage closure, as well as superior (roof) and inferior (floor) interpulmonary vein lines. Roof and floor lines were alternatingly ablated by dual energy or RF only. Three months post-TTA, endocardial mapping with optional gap closure was yet performed in 12 patients.

Results: Apart from one post-TTA pacemaker implantation and one minithoracotomy for bleeding, respectively, no major morbidity was observed. Only 2 (9%) of 23 PVI were found not completely isolated. In contrast, 8 of 22 (36%) roof or floor lines were incomplete. Of note, dual energy lines were less likely to be incomplete than RF only lines (2 of 9, 18% vs. 6 of 13, 46%, p = ns). Among 11 patients with implantable, continuous AF monitoring, only 2 (18%) had any AF burden (1 AF and 1 atypical flutter). Finally, the remaining six patients without continuous monitoring have never experienced any signs of recurrent AF, and all serial Holter EKGs were with no pathology.

Conclusion: Linear ablation lines were more likely to be gapless and transmural, if dual energy sources were used. TTA in combination with dual energy sources is highly efficient to restore SR. Further study will evaluate whether dual energy lines outside the box can improve outcome.