Catheter Ablation -> Atrial Fibrillation & Atrial Flutter: -> Clinical Trials / Outcomes D-PO01 - Featured Poster Session (ID 11) Poster

D-PO01-131 - The Impact Of Additional Freeze Cycles On Ablation Lesions And Gaps Analyzed By Delayed-enhancement Mri For Cryoballoon Ablation Of Paroxysmal Atrial Fibrillation In The Ad-balloon Study (ID 931)

Abstract

Background: Pulmonary vein isolation (PVI) with the second-generation cryoballoon (CB2) has been demonstrated to be highly effective in achieving freedom from paroxysmal atrial fibrillation (PAF), however, there is some debate concerning the optimal freeze cycles.
Objective: To investigate the validity of additional 3-minute freeze cycles after achieving a PVI in PAF patients treated with a CB2 ablation by using delayed-enhancement MRI (DE-MRI).
Methods: The AD-Balloon study was designed as a prospective, multicenter, and randomized clinical trial for investigation of the optimal strategy for the CB2 ablation. Patients were randomly assigned to treatment with 3-min additional freeze cycles after PVI (AD group) or without it (Non-AD group). The DE-MRI was performed at 1-2 months after the PVI and analyzed to assess the impact of additional freeze cycles on ablation lesions and gaps in 62 patients (28 patients in the AD group and 34 in the Non-AD group).
Results: A complete PVI was achieved in all patients. With the DE-MRI, there were no significant difference in the ablation lesion volume between the AD group and Non-AD group (left superior PV; 4.3±2.2 vs. 4.1±1.4mm3, left inferior PV; 4.6±2.5 vs. 4.7±1.9mm3, right superior PV; 3.3±1.8 vs. 3.6±1.4mm3, right inferior PV; 3.3±1.4 vs. 3.2±1.3mm3). The ablation lesion length was also similar between the AD group and Non-AD group (left superior PV; 74.9±10.6 vs. 74.4±7.9mm, left inferior PV; 64.4±8.8 vs. 66.1±8.1mm, right superior PV; 77.0±9.6 vs. 77.5±8.7mm, right inferior PV; 68.0±7.6 vs. 68.1±8.5mm). With the DE-MRI, gaps on the PVI lines were detected in 13 of 28 patients (46%) in the AD group and in 12 of 34 (36%) in the Non-AD group (P=0.38). There were 6 gaps at the left PVs and 20 gaps at the right PVs in the AD group. In the non-AD group, there were 5 gaps at the left PVs and 9 gaps at the right PVs. The time to the PVI was significantly longer in PVs with gaps than those without gaps (63±22 vs. 43±25 sec). The cumulative event (atrial tachyarrhythmia) free rate at 1-year was 82 % in the AD group and 94% in the Non-AD group (log-rank test P=0.15).
Conclusion: No additional benefit on ablation lesion size and residual gaps was found in the patients receiving additional 3-minute freeze cycles after achieving PVI with the CB2 ablation.
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