Radiofrequency Versus Cryoballoon Catheter Ablation for Paroxysmal Atrial Fibrillation: Durability of Pulmonary Vein Isolation and Effect on Atrial Fibrillation Burden: The RACE-AF Randomized Controlled Trial

Abstract

Background - Recurrent paroxysmal atrial fibrillation (PAF) after catheter ablation is presumably caused by failure to achieve durable pulmonary vein isolation (PVI). The primary methods of PVI are radiofrequency (RF) and cryoballoon (CRYO) catheter ablation, but these methods have not been directly compared with respect to PVI durability and the effect thereof on AF burden (% of time in AF). Methods - Accordingly, we performed a randomized trial including 98 patients (68% male, 61 [55-67] years) with PAF assigned 1:1 to PVI by contact-force sensing, irrigated RF catheter or second-generation CRYO catheter. Implantable cardiac monitors were inserted ≥1 month before PVI for assessment of AF burden and recurrence, and all patients, irrespective of AF recurrence, underwent a second procedure 4-6 months after PVI to determine PVI durability. Results - In the second procedure, 152/199 (76%) pulmonary veins (PVs) were found durably isolated after RF and 161/200 (81%) after CRYO (NS), corresponding to durable isolation of all veins in 47% of patients in both groups (NS). Median AF burden before PVI was 5.4% (interquartile range: 0.5-13.0%) vs. 4.0% (0.6-18.1%), RF vs. CRYO, and reduced to 0.0% (0.0-0.1%) and 0.0% (0.0-0.5%), respectively - a reduction of 99.9% (92.9-100.0%) and 99.3% (85.9-100.0%) (all NS). AF burden after PVI significantly correlated to the number of durably isolated PVs (p < 0.01), but 9/45 (20%) patients with durable isolation of all veins had recurrence of AF within 4-6 months after PVI (excluding a 3-month blanking period). Conclusions - PVI by RF and CRYO catheter ablation produce similar moderate to high PVI durability. Both treatments lead to marked reductions in AF burden, which is related to the number of durably isolated PVs. However, for one fifth of PAF patients, complete and durable PVI was not sufficient to prevent even short-term AF recurrence.

Cryoballoon vs. radiofrequency catheter ablation: insights from NOrwegian randomized study of PERSistent Atrial Fibrillation (NO-PERSAF study)

“… 14 , 15 For paroxysmal AF, non-inferiority of clinical outcomes of CBA has been verified by the FIRE AND ICE study 5 and the CIRCA-DOSE study, 6 while the similar durability of PVI has been confirmed by the RAZE-AF study. 7 The success rate of CBA for persistent AF ranged from 60% to 70% at 1-year follow-up. 8 , 9 Recently, Chun et al .…”

Strategies for repeat ablation for atrial fibrillation: A multicentre comparison of nonpulmonary vein versus pulmonary vein target ablation

“…In the RACE-AF trial, all patients underwent a repeat procedure 4-6 months after the first AF ablation. 2 Twenty percent of the patients with isolated PVs had AF recurrences, despite a 96% reduction of AF burden in these patients. 2 In our study, we found that 56% of patients with non-PV target ablation and isolated PVs reported an atrial tachyarrhythmia recurrence.…”

“…2 Twenty percent of the patients with isolated PVs had AF recurrences, despite a 96% reduction of AF burden in these patients. 2 In our study, we found that 56% of patients with non-PV target ablation and isolated PVs reported an atrial tachyarrhythmia recurrence. Our study does not provide data on burden reduction.…”

“…13 Reconduction after initial PV isolation has been associated with more atrial arrhythmia recurrences; it remains unclear whether non-PV target ablation in addition to PV reisolation (or wider PV antrum isolation) should be preferred during a repeat AF ablation. 2,[14][15][16][17] This study compares non-PV target with PV target ablation strategies during first repeat AF ablation in a multicentre retrospective cohort. We further sought to identify the prognostic implications of isolated PVs at repeat ablation in patients undergoing a non-PV target ablation strategy.…”

“…[3][4][5] Despite improved durability of PV isolation with contemporary ablation techniques, 47% of patients have one or more reconnected PVs within 4-6 months after the index PV isolation procedure. 2,6 Approximately 18% of patients undergo repeat AF ablation within 1 year after the first AF ablation. 7 In a recent multicentre randomized trial, electrophysiological mapping at the repeat AF ablation procedure revealed one or more reconnected PVs in up to 90% of the patients after contemporary AF ablation, likely suggesting the clinical need for reisolation.…”