Abstract
Funding Acknowledgements
Type of funding sources: None.
Background
Complete electrical pulmonary vein isolation (PVI) by cryo-balloon approach is a well-established ablation strategy of atrial fibrillation (AF). Recently, a new cryoablation system (POLARx) with unique features has been made available for clinical use. To date, no data exist on procedural characteristics of this system in a multicentric clinical practice.
Purpose
We aimed to characterize the initial experience of this technology in the Italian clinical practice.
Methods
Consecutive patients (pts) undergoing AF ablation from the CHARISMA registry at 5 Italian centres were included. Protocol-directed cryoablation was delivered for 180 sec or 240 sec according to operator’s preference for isolation achieved in ≤60 sec, or 240 sec if isolation occurred >60 sec or when time to isolation (TTI) was not available. The ablation endpoint was PV isolation as assessed by entrance and exit block.
Results
Two-hundred sixty-two cryoapplications from 49 pts (194 PVs) were analyzed. PVI was achieved with cryoablation only in all pts. The mean number of freeze applications per pt was 5.3 ± 1.5 (1.3 ± 0.6 for LIPV, LSPV and RSPV, 1.6 ± 1.3 for RIPV), with 143 (73.7%) PVs treated in a single-shot fashion (38, 19.6% with 2 shots; 13, 6.7% with more than 2 shots). Sixteen (33%) pts were treated with a single freeze to each of the PVs. The mean nadir temperature was -55.5 ± 6.9 °C and was colder than -50°C in 83% of the PVs. TTI information was evaluable in 120 (46%) cryoapplications with a median TTI of 47 [32-75] sec (median temperature at TTI = -49 [-53 to -42] °C). The mean time to target -40 °C (TTT) was 30.1 ± 6.9 sec with a TTT < 60 sec achieved in 99.2% of the cryoapplications; the mean thaw time to 0 °C was 18.6 ± 5.8 sec (thaw time >15 sec in 70.3% of the cryoapplications). The mean PV occlusion grade (rank 1-4) was 3.6 ± 0.6 (grade 2 in 5.2% of the cases, grade 3 in 25.6% and grade 4 in 69.2%). No complications were observed at 30 days post-procedure.
Conclusion
In this first multicentric experience in a clinical practice setting, the novel cryo-balloon system proved to be safe and effective and resulted in a high proportion of successful single-freeze isolation. Cooling parameters seem to be slightly different from reference cryo-balloon technology.
Chronic rate dependent exit block after pulmonary vein isolation