Pulmonary vein reconnection and repeat ablation characteristics following cryoballoon-compared to radiofrequency-based pulmonary vein isolation.

BACKGROUND: Despite advances in efficacy and safety of pulmonary vein isolation (PVI), atrial fibrillation (AF) recurrence after PVI remains common. PV-reconnection is the main finding during repeat PVI procedures performed to treat recurrent AF. OBJECTIVE: To analyze pulmonary vein (PV) reconnection patterns during repeat ablation procedures in a large cohort of consecutive patients undergoing radio frequency or cryoballoon-based PVI. METHODS: Retrospective analysis of PV-reconnection patterns and analysis of re-ablation strategies in consecutive index RF- and CB-based PVI and their respective re-ablation procedures during concomitant usage of both energy sources at a single high-volume center in Germany. RESULTS: A total of 610 first (06/2015-10/2022) and 133 s (01/2016-11/2022) repeat ablation procedures after 363 (60%) RF- and 247 (40%) CB-based index PVIs between 01/2015 and 12/2021 were analyzed. PV-reconnection was found in 509/610 (83%) patients at first and 74/133 (56%) patients at second repeat procedure. 465 of 968 (48%) initially via CB isolated PVs were reconnected at first re-ablation but 796 of 1422 initially RF-isolated PV (56%) were reconnected (OR: 0.73 [95% CI: 0.62-0.86]; p < .001). This was driven by fewer reconnections of the left PVs (LSPV: OR: 0.60 [95% CI: 0.42-0.86]; p = .005 and LSPV: 0.67 [0.47-0.95]; p = .026). PV-reconnection was more likely after longer, RF-based index PVI and in older females. Repeat procedures were shorter after CB-compared to after RF-PVI. CONCLUSIONS: Reconnection remains the most common reason for repeat AF ablation procedures after PVI. Our data suggest to preferentially use of the cryoballoon during index PVI, especially in older women.

Bipolar ablation of therapy-refractory ventricular arrhythmias: application of a dedicated approach.

AIMS: Bipolar radiofrequency ablation (B-RFA) has been reported as a bail-out strategy for the treatment of therapy refractory ventricular arrhythmias (VA). Currently, existing setups have not been standardized for B-RFA, while the impact of conventional B-RFA approaches on lesion formation remains unclear. METHODS AND RESULTS: (i) In a multicentre observational study, patients undergoing B-RFA for previously therapy-refractory VA using a dedicated B-RFA setup were retrospectively analysed. (ii) Additionally, in an ex vivo model lesion formation during B-RFA was evaluated using porcine hearts. In a total of 26 procedures (24 patients), acute success was achieved in all 14 ventricular tachycardia (VT) procedures and 7/12 procedures with premature ventricular contractions (PVC), with major complications occurring in 1 procedure (atrioventricular block). During a median follow-up of 211 days in 21 patients, 6/11 patients (VT) and 5/10 patients (PVC) remained arrhythmia-free. Lesion formation in the ex vivo model during energy titration from 30 to 50 W led to similar lesion volumes compared with initial high-power 50 W B-RFA. Lesion size significantly increased when combining sequential unipolar and B-RFA (1429 mm3 vs. titration 501 mm3 vs. B-RFA 50 W 423 mm3, P < 0.001), an approach used in overall 58% of procedures and more frequently applied in procedures without VA recurrence (92% vs. 36%, P = 0.009). Adipose tissue severely limited lesion formation during B-RFA. CONCLUSION: Using a dedicated device for B-RFA for therapy-refractory VA appears feasible and safe. While some patients need repeat ablation, success rates were encouraging. Sequential unipolar and B-RFA may be favourable for lesion formation.

Spatial correction improves accuracy of catheter positioning during ablation of premature ventricular contractions: differences between ventricular outflow tracts and other localizations.

BACKGROUND: Hybrid activation mapping is a novel tool to correct for spatial displacement of the mapping catheter due to asymmetrical contraction of myocardium during premature ventricular contractions (PVC). The aim of this study is to describe and improve our understanding of spatial displacement during PVC mapping as well as options for correction using hybrid activation mapping. METHODS AND RESULTS: We analyzed 5798 hybrid mapping points in 40 acquired hybrid maps of 22 consecutive patients (age 63 ± 16 years, 45% female) treated for premature ventricular contractions (PVCs). Median PVC-coupling interval was 552 ms (IQR 83 ms). Spatial displacement was determined by measuring the dislocation of the catheter tip during PVC compared to the preceding sinus beat. Mean spatial displacement was 3.8 ± 1.5 mm for all maps. The displacement was 1.3 ± 0.4 mm larger for PVCs with non-outflow-tract origin compared to PVCs originating from the ventricular outflow tracts (RVOT/LVOT; p = 0.045). Demographic parameters, PVC-coupling-interval and chamber of origin had no significant influence on the extent of spatial displacement. CONCLUSION: Ectopic activation of the ventricular myocardium during PVCs results in spatial displacement of mapping points that is significantly larger for PVCs with non-outflow-tract origin. The correction for spatial displacement may improve accuracy of radiofrequency current (RFC)-application in catheter ablation of PVCs.