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

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.MethodsThirty-four consecutive patients (26 men, mean age: 56.7±9.3years) 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 4mm irrigated-tip catheter. All patients underwent CT-scan evaluation before discharge to detect acute PV stenosis.ResultsPVI could be achieved in all patients. Mean procedure duration was 230±42min and mean fluoroscopy time was 52±13min. 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±3months, 28 patients (82%) did not experience AF recurrence (including six patients on antiarrhythmic drugs).ConclusionsOur 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