Background: Adenosine triphosphate (ATP) testing reveals dormant pulmonary vein (PV) conduction after electrical PV isolation (PVI). This study aimed to evaluate the incidence of latent PV conduction after cryothermal PVI.
Methods: Fifty-four consecutive paroxysmal atrial fibrillation patients undergoing cryothermal PVI were prospectively enrolled. PVI was performed with one 28-mm second-generation balloon using a 3-minute freeze technique, and touch-up lesions were created by focal cryothermal applications. ATP testing was performed following PVI with a 20-mm circular mapping catheter placed in each PV.
Results: Of 217 PVs, 205 (94.5%) were isolated using a cryoballoon, and 12 required additional focal ablation. ATP testing was performed in 46 patients for 173 and 8 PVs, which were isolated by cryoballoons and focal ablation, respectively. No dormant PV conduction was provoked in any PVs, which were isolated by cryoballoons, whereas 4 (50.0%) out of 8 PVs requiring focal ablation had transient ATP-provoked reconnections (0 vs. 50.0%, P < 0.0001) with a median duration of 11.3 (10.7-17.1) seconds. The latent PV conduction site was identical to the residual conduction gap site after cryoballoon ablation in all. All latent conduction was successfully eliminated by 2 (2.0-9.5) additional focal applications. At a mean follow-up of 7.7 ± 1.6 months, 81.5% of the patients were arrhythmia free after a single procedure.
Conclusions: No dormant PV conduction was provoked in PVs, which were isolated by 28-mm second-generation cryoballoons, but was provoked in 50% of PVs, which were isolated by focal cryoablation. These findings suggest that creating contiguous lesions is essential for eliminating dormant conduction in cryothermal ablation.
Keywords: adenosine; atrial fibrillation; cryoablation; dormant conduction; pulmonary vein isolation.
© 2015 Wiley Periodicals, Inc.