Impact of a time-to-effect-guided ablation protocol in cryoballoon ablation on the durability of pulmonary vein isolation

Background Cryoballoon (CB)-based pulmonary vein isolation (PVI) has proven to be as effective as radiofrequency-based ablation. Different ablation protocols took the individual time-to-isolation (TTI) into account aiming at shorter but equally or even more effective freeze cycles. The current study sought to assess the impact of the TTI on PVI durability in patients undergoing a repeat procedure for recurrence of atrial tachyarrhythmia (ATA). Methods and Results In 205 patients with ATA recurrence after previous CB-based PVI, a total of 806 pulmonary veins (PVs) were identified. A total of 126 out of 806 PVs (16%) were previously treated with a TTI-guided ablation (Protocol #1; TTI + 120 s), in 92/806 (11%) PVs TTI was only monitored (m) but fixed freeze cycles were applied (Protocol #2; mTTI) and in 588/806 (73%) a fixed freeze cycle was applied without mTTI. There was no difference in the PV-reconduction rate between the groups (p = .23). The right inferior pulmonary vein (RIPV) showed overall significantly higher reconduction rates compared to the other PVs (RIPV-left inferior PV p < .003, -left superior PV p < .001, -right superior PV p < .013). Twenty-one patients (10%) were demonstrated to have only electrical reconduction of the RIPV, while all other PVs were still electrically isolated. Conclusions The TTI-based CB ablation protocol did not show significant differences regarding PV-reconduction rates compared to the other ablation protocols.