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.

Reconduction After Second-Generation Cryoballoon-Based Pulmonary Vein Isolation　- Impact of Different Ablation Strategies.

BACKGROUND: The second-generation cryoballoon (CB2) has demonstrated high procedural efficacy and convincing clinical success rates for pulmonary vein isolation (PVI). Nevertheless, data on the impact of different ablations protocols on durability are limited. The aim was to comparing the durability of PVI following 3 different ablation strategies in patients with recurrence of atrial fibrillation or atrial tachycardia undergoing repeat procedures.Methods and Results:In 192 patients, a total of 751 PVs were identified. All PVs were successfully isolated during index PVI. Thirty-one out of 192 (16%) patients were treated with a bonus-freeze protocol (group 1), 67/192 (35%) patients with a no bonus-freeze protocol (group 2), and 94/192 (49%) patients with a time-to-effect-guided protocol (group 3). Persistent PVI was documented in 419/751 (55.8%) PVs, and in 41/192 (21%) patients, all PVs were persistently isolated. The total rate of PV reconnection was not significantly different between the groups (P=0.134) and the comparison of individual PVs revealed no differences (P-values for RSPV: 0.424, RIPV: 0.541, LSPV: 0.788, LIPV: 0.346, LCPV: 0.865). The procedure times were significantly reduced by omitting the bonus-freeze and applying individualized application times (group 1: 123.4±31.5 min, group 2: 112.9±39.8 min, group 3: 86.67±28.4 min, P<0.001). CONCLUSIONS: Comparing 3 common ablation protocols, no differences for durable PVI were detected. Procedure times were significantly reduced by omitting the bonus-freeze cycle and by applying individualized application times.