Is radiofrequency energy a necessary and safe complement to cryotherapy for successful pulmonary vein isolation?

Abstract

Introduction: Pulmonary vein (PV) isolation is considered the cornerstone of atrial fibrillation (AF) catheter ablation. PV isolation (PVI) by means of cryotherapy has emerged as a promising technique due to both a low thrombogenicity and reduced risk of PV stenosis. The evaluation (need/efficiency/safety) of hybrid therapy (defined as the use of cryotherapy followed by that of radiofrequency energy in a given patient) is the aim of the present study. Methods: Thirty-four consecutive patients (26 men, mean age: 56.7 ± 9.3 years) with symptomatic drug-refractory paroxysmal AF underwent PVI using a balloon-cryotherapy (BCT). A maximum of four cryotherapy applications was applied per PV and disconnection assessed thereafter using a circular LASSO® catheter. When necessary, PV disconnection was then performed using a 4 mm irrigated-tip catheter. All patients underwent CT-scan evaluation before discharge to detect acute PV stenosis. Results: PVI could be achieved in all patients. Mean procedure duration was 230 ± 42 min and mean fluoroscopy time was 52 ± 13 min. Hybrid therapy was needed to achieve PVI in 26 of 34 (76%). With cryoablation solely, PVI was achieved in 90 of 136 (66%) targeted veins, efficacy being higher in superior as compared to inferior PVs (87% vs. 46%, p < 0.001). Besides one patient with permanent right phrenic nerve injury, no other procedure-related complications were observed. After a mean follow-up period of 8 ± 3 months, 28 patients (82%) did not experience AF recurrence (including six patients on antiarrhythmic drugs). Conclusions: Our study suggests that hybrid ablation therapy is necessary in most patients to achieve PV disconnection after a maximum of four blinded applications of balloon-cryotherapy (especially in inferior PVs), with a significant short-term success rate.

Keywords

• Pulmonary veins
• Balloon-cryotherapy
• Hybrid therapy