P899The impact of the pulmonary veins and left atrium anatomy on the success of exclusively a 28-mm second - generation cryoballoon ablation in patients with paroxysmal Atrial fibrillation

Purpose: When pulmonary vein isolation (PVI) using cryoballoon (CB) in patients with paroxysmal atrial fibrillation (PAF) is performed, it is ideal to succeed PVI exclusively with CB. However, the pulmonary veins (PV) and left atrium (LA) anatomy have a lot of variant, which sometimes may require touch-up ablation. The purpose of this study was to evaluate the impact of PV and LA anatomy on the success of exclusively a 28-mm second - generation CB ablation. Methods: A total of 60 PAF patients undergoing PVI using a 28-mm second-generation CB were enrolled in this study. For each patient, multi-detector computed tomography was performed before the procedure. The PV anatomy was evaluated the PV drainage patterns, the dimensions of every PV ostium, intervenous ridges (IVRs), and the left PV-left atrial appendage ridge. Cryothermal PVI using a 28-mm second-generation CB was performed with single application of 180 seconds per each PV. In case of residual PV conduction, we made a touch- up ablation. As to cryothermal data, We collected the time when the balloon temperature (BT) reached 0°C, the BT 30 seconds after start freezing, the minimum BT and the thawing time from freezing stop to deflating the balloon from every cryothermal application data in the cryothermal console. Results: Four discrete PVs, Left common PV and a right accessory PV were presented in 55 (92 %), 1 (2%), 4 (6%) of the patients, respectively. Out of 243 PVs, 211 (87%) PVs were succeeded in PVI with exclusively the CB. 32 PVs required touch-up ablations (left superior PV; 6/59 PVs, left inferior PV; 6/59 PVs, right superior PV; 1/60 PV, right inferior PV; 17/60 PVs, right accessory PV; 2/4PVs). Compared the required touch-up ablation group (Touch-up) and the exclusively CB group (No Touch-up), in left superior PVI with the CB, LA diameter in Touch-up group was significantly larger than No Touch-up group (38±4.3 vs. 33±4.1mm, p = 0.0095). There was a significant difference the width of IVR and the left PV-left atrial appendage ridge between 2 groups in left inferior PVI with the CB (6.5±4.6 vs. 4.3±2.3 mm, p = 0.0275, 4.2±1.5 vs. 2.8±1.4 mm, p = 0.047, respectively). It was no significant difference between two groups in right side PVIs with the CB. As to cryothermal data, mean minimum BT in Touch-up group was significantly higher than No Touch-up group. Furthermore, mean minimum BTs in Touch-up group were above - 40°C in all PVIs but right superior PV with the CB. Conclusion: A PAF patient who has an enlarged LA, a wide IVR and thick of left PV-left atrial appendage ridge may not be suitable to isolate PVI with exclusively a 28-mm second - generation CB ablation. It is necessary to freeze at least less than -40°C to isolate each PV with this device.