Abstract 324 Electrical PV reconnection or durable PVI at repeat ablation after standardized TTI based cryo-ablation: What are the procedural determinants and is there room for improvement?

Methods: From the local prospective observational single-center registry, all patients undergoing repeat ablation due to recurrence after a single initial advanced CBA were included in this analysis. The initial CBA was performed according to a standardized CBA protocol with a rigid cut off for bonus application with optimized repositioning (TTI > 45sec.) and applications of 180 sec. In all PVs without TTI, a bonus application was performed following the electrical disconnection. In PVs with TTI >90s the freeze was terminated and the balloon was repositioned. Single-shot isolation was defined as PV isolation detected by a spiral map catheter after the first cryo-application.

At repeat ablation, ultra-high density electroanatomical 3D mapping (voltage and activation) of the LA was performed.
Two groups were created: Group A included PVs with durable isolation at repeat ablation and group B included PVs with electrical reconnection. Statistical analysis was performed with SPSS and established descriptive methods.

Results: A total of 2,410 patients underwent CBA performed with generation 2, 3 or 4 between 5/2012 and 3/2021. Of those, 219 patients (9.1%) underwent repeat ablation, after a median time span of 15

months one hundred and fifty (69%) patients presented with persistent AF. Median age was 70 years. Ninety three (42%) were female. Durable PVI of all veins was found in 139/219 patients (63.5%)
A total of 856 PVs were evaluated. Of those, 760 PVs (88.8%) were durably isolated (group A), and 96 (11.2%) showed reconnection (group B). There was no significant difference of isolation rates between the different anatomical PV types (LS (86.6%), LI (91.3%), RI (91.2%), RS (86.4%), RM (95.5%), LC (84.8%) p = 0.461).

No differences were observed between the groups for the number of applications per PV, the total application time per PV, the TTI, the rate of detected TTIs and the nadir balloon temperature. Those durably isolated PV were more frequently isolated by a single-shot in the initial procedure as compared to those demonstrating reconnection (76.8 vs. 64.6 % p = 0.007).

Conclusion: Standardized cryoballoon ablation following a strict TTI-based ablation protocol with a rigid cut-off for bonus application (TTI > 45 sec.) and a bonus application in freezes without TTI seems to enhance durable isolation even if acute PVI is difficult to obtain. However, anatomical aspects in a balloon-based procedure are the main challenges of CBA. The observed association of durable PVI and an effective first cryo-application (single shot) underlines the crucial role of optimized and precise balloon occlusion.

Clin Res Cardiol (2022). https://doi.org/10.1007/s00392-022-02087-y
Electrical PV reconnection or durable PVI at repeat ablation after standardized TTI based cryo-ablation: What are the procedural determinants and is there room for improvement?
L. Rieß¹, J. Pongratz¹, U. Dorwarth¹, M. Wankerl¹, F. Straube¹, E. Hoffmann¹
¹Klinik für Kardiologie und Internistische Intensivmedizin, München Klinik Bogenhausen, München;
Background: Pulmonary vein isolation (PVI) by means of cryoballoon ablation (CBA) is a safe and effective strategy to achieve durable PVI in the first procedure, however patients still experience recurrence of atrial arrhythmias associated with electrical reconnection of pulmonary veins (PVs). Different cryoballoon ablation protocols are proposed, but there is still a debate on the ideal protocol design. TTI has been established as an unique predictor for PVI durability. The aim was to evaluate our TTI-based ablation protocol by comparison of reconnected and isolated PVs in patients undergoing repeat ablation due to recurrence of atrial arrhythmia. Methods: From the local prospective observational single-center registry, all patients undergoing repeat ablation due to recurrence after a single initial advanced CBA were included in this analysis. The initial CBA was performed according to a standardized CBA protocol with a rigid cut off for bonus application with optimized repositioning (TTI > 45sec.) and applications of 180 sec. In all PVs without TTI, a bonus application was performed following the electrical disconnection. In PVs with TTI >90s the freeze was terminated and the balloon was repositioned. Single-shot isolation was defined as PV isolation detected by a spiral map catheter after the first cryo-application. At repeat ablation, ultra-high density electroanatomical 3D mapping (voltage and activation) of the LA was performed. Two groups were created: Group A included PVs with durable isolation at repeat ablation and group B included PVs with electrical reconnection. Statistical analysis was performed with SPSS and established descriptive methods. Results: A total of 2,410 patients underwent CBA performed with generation 2, 3 or 4 between 5/2012 and 3/2021. Of those, 219 patients (9.1%) underwent repeat ablation, after a median time span of 15 months one hundred and fifty (69%) patients presented with persistent AF. Median age was 70 years. Ninety three (42%) were female. Durable PVI of all veins was found in 139/219 patients (63.5%) A total of 856 PVs were evaluated. Of those, 760 PVs (88.8%) were durably isolated (group A), and 96 (11.2%) showed reconnection (group B). There was no significant difference of isolation rates between the different anatomical PV types (LS (86.6%), LI (91.3%), RI (91.2%), RS (86.4%), RM (95.5%), LC (84.8%) p = 0.461). No differences were observed between the groups for the number of applications per PV, the total application time per PV, the TTI, the rate of detected TTIs and the nadir balloon temperature. Those durably isolated PV were more frequently isolated by a single-shot in the initial procedure as compared to those demonstrating reconnection (76.8 vs. 64.6 % p = 0.007). Conclusion: Standardized cryoballoon ablation following a strict TTI-based ablation protocol with a rigid cut-off for bonus application (TTI > 45 sec.) and a bonus application in freezes without TTI seems to enhance durable isolation even if acute PVI is difficult to obtain. However, anatomical aspects in a balloon-based procedure are the main challenges of CBA. The observed association of durable PVI and an effective first cryo-application (single shot) underlines the crucial role of optimized and precise balloon occlusion.
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