0536: Use of 2nd generation cryoballoon with reduced dosing strategy is superior to 1st generation cryoballoon for paroxysmal atrial fibrillation ablation

Background With the technical properties of the 2 nd generation (Arctic Front Advance, AFA) cryoballoon (CB), we postulated we could reduce complication rate without impairing efficacy in the treatment of paroxysmal atrial fibrillation if we stop the bonus application. Method Since January 2011, all patients referred to our institution for ablation of symptomatic drug refractory paroxysmal atrial fibrillation were included (n=129). Until June 2012, the ablation was performed with the Arctic Front cryoballoon (AF-CB) with application of 4mm bonus freeze after PVI (n=47). From July 2012 to December 2013, the ablation procedure was performed with the AFA-CB, without bonus freeze after PVI in 82 patients. All patients were seen at 4 to 6 month follow-up. They underwent at least 1 Holter monitoring in the post-operative period (2-4 month after ablation). Mid-term clinical success was defined by the association of sinus rhythm on ECG and Holter monitoring and lack of symptoms. Results Compared to the AFCB group, there was a significant reduction of the procedure time (131 min vs 95 min; p 2 vs 20 Gy/cm 2 ; p = 0.04) in the AFACB group. Isolation of the 4 PVs was obtained in 89 and 96% (p = 0.24) before performing a touch up with a Freezor Max catheter in the AFCB and AFACB group respectively. Using our definition for success, the mid-term success rate was higher in the AFA-CB group as compared with that of in the AF-CB group (78% vs 53% p = 0.01; CI [1,3 - 6,5]). Significant complications occurred in 9% in the AFA-CB group versus 13% in the AF-CB group (p = 0.44). There was no difference regarding the rate of phrenic nerve palsy (7% AF-CB group vs 5% AFA-CB group;p=0.24). Conclusion The lack of a bonus freeze application after PVI allows to significantly reducing the procedure time and the X-ray exposure. Even when using a reduced dosing strategy, our study shows the AFA-CB leads to a better outcome as compared to the AF-CB.