Key result
TTI-guided cryoballoon ablation shows no difference in PV reconnection rates vs. a fixed protocol.
Why the study?
The optimal freeze duration in cryoballoon PVI is unknown, and evidence of long-term PV reconnection rates after TTI-based cryoballoon ablation is sparse.
Does a time-to-isolation (TTI)-guided cryoballoon ablation protocol provide comparable long-term durable pulmonary vein isolation to a fixed ablation protocol in patients with atrial fibrillation?
Cohort (n=219)
No
Does a time-to-isolation (TTI)-guided cryoballoon ablation protocol provide comparable long-term durable pulmonary vein isolation to a fixed ablation protocol in patients with atrial fibrillation?
Individualized cryoenergy application based on time-to-isolation leads to comparable long-term pulmonary vein isolation durability as traditional, longer fixed-duration freezes.
TTI-guided cryoablation shows comparable PV reconnection in this observational redo cohort; leaves open whether titration improves durability, requiring randomized trials.
Introduction: The optimal freeze duration in cryoballoon pulmonary vein isolation (PVI) is unknown. TTI-based titration of cryoenergy allows individualized freeze duration and has emerged as a favorable ablation strategy in PV cryoablation. In a recent study, we demonstrated that omission of a bonus freeze and reduction in freeze duration to a minimum of 2 min in the case of short TTI led to comparable arrhythmia recurrence rates. Whereas clinical outcome seems to be comparable to fixed freeze duration, evidence of long-term PV reconnection rates in patients undergoing TTI-based cryoballoon ablation is sparse. Aim of the study: To evaluate the procedural efficacy of a single 2-min freeze for PVI, we assessed PV conduction recovery after cryoballoon PVI with a TTI-guided titration of freeze duration compared to a fixed ablation protocol. Methods and Results: We included consecutive patients with atrial fibrillation (AF) recurrence undergoing a second ablation procedure after the initial cryoballoon procedure. The second AF ablation procedure was performed by the 3D-mapping system and radiofrequency ablation technique. A total of 219 patients (age: 66.2 ± 10.8 years, 53% female, paroxysmal AF: 53%) treated with the TTI-guided protocol (174 patients, 685 PV) or fixed protocol (45 patients, 179 PV) showed comparable total reconnection rates (TTI: 36.9% vs. fixed: 31.8%, p = 0.21). The PV reconnection rate was not statistically different for PVs treated with a 2-min freeze in case of short TTI, compared to longer freeze duration. Interestingly, the PV reconnection rate was lower in LIPVs treated with the fixed protocol (13% vs. 31%, p = 0.029). In the TTI group, 17 out of 127 patients (15%) had durable isolation of all PVs, whereas in 8 out of 40 patients (20%) in the fixed group, all PVs were still isolated (p = 0.31). Conclusions: overall reconnection rate was not different using a TTI-guided ablation protocol compared to a fixed ablation protocol, whereas the LIPV reconnection rate was significantly lower in patients treated with a fixed ablation protocol.
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Pott et al. (2022) conducted a cohort in Atrial fibrillation recurrence after initial cryoballoon pulmonary vein isolation (n=219). Time-to-isolation (TTI)-guided cryoballoon ablation vs. Fixed freeze duration cryoballoon ablation was evaluated on Total pulmonary vein reconnection rate during second ablation (p=0.21). Time-to-isolation (TTI)-guided cryoballoon ablation resulted in comparable overall pulmonary vein reconnection rates to a fixed ablation protocol (36.9% vs. 31.8%, p=0.21) in patients undergoing a redo procedure.
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