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Background/Introduction: Cryoballoon ablation is an established therapy for PVI in paroxysmal and persistent AF. However, there is discussion about the best reablation strategy in case of arrhythmia recurrence.
Purpose: Determination of PV reconduction and arrhythmia mechanisms using ultra-high-density mapping in parox. (PAF) and persist. AF (persAF) patients undergoing redo procedure after a single cryoballoon PVI to evaluate the most adequate reablation strategy.
Methods: We studied consecutive patients with arrhythmia recurrence following a single 2nd, 3rd or 4th generation 28mm cryoballoon ablation for PAF or persAF. Patients underwent multi-electrode (64) ultra-high density mini-basket catheter mapping during spontaneous or induced rhythm followed by RF reablation. Mapping included determination of left atrial volume, PV conduction, analysis of left atrial substrate (dense scar (< 0.1mV), moderate scar (0.1 – 0.5mV), healthy tissue (> 0.5mV), substrate quantification and distribution as well as mapping of spontaneous or inducible atrial tachycardia.
Results: One hundred forty-six consecutive patients were included, age 69±9yrs, 49% female, left atrial diameter 45±6mm. Time interval between cryoballoon ablation and the redo procedure was 27±21 months. The initial indication for ablation was PAF in 18% and persAF in 82% of patients. Mapping time was 30±11 min for acquisition of 10,569±6,180 electrograms. High density mapping showed a complete wide circumferential isolation of all veins in 71% of patients (56% PAF patients, 75% pesAF patients; n.s.). Regarding the veins, 91% were found isolated (86% veins in PAF patients, 92% in persAF patients; n.s.). Left atrial fibrotic area was 20±18cm2 (20%) (dense scar 7±11 cm2 (7%), moderate scar 13±12 cm2 (13%)). Left atrial volume was significantly smaller in PAF vs PersAF patients (149±29cc vs 179±33cc; p≤0.0001), however, percentage of left atrial fibrotic area was not significantly different (15% vs. 21%). Based on UHD-mapping (during SR, ongoing and/or induced arrhythmia), the following ablation strategies were applied in PAF patients: 33% PVI only, 11% PVI + substrate / AT, 15% extra PV trigger, 26% substrate based AT and 30% substrate only. In patients with persisAF, 9% of patients required PVI only, 16% PVI + substrate / AT, 8% extra PV trigger, 34% substrate based AT and 41% substrate ablation only.
Conclusion: Based on a low rate of PV reconduction and proof of significant LA fibrosis and atrial tachycardia in arrhythmia recurrence after one cryoballoon PVI in both persistent and paroxysmal AF, a cryo redo is not justified for any form of AF. High density mapping is an adequate strategy for redo procedures to elucidate underlying arrhythmia mechanisms as a basis for and individualized mapping and substrate based RF ablation irrespective of AF type and left atrial size.
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