Fehmi Keçe

Optimizing Ablation Duration using Dormant Conduction 129 6 6.2.2 Ablation procedure Anti-arrhythmic drugs (AAD) except amiodarone were discontinued 5-half-lives before ablation. In all patients, a single ablation with the 28 mm second-generation cryoballoon (Arctic Front Advance, Medtronic Inc., Minneapolis, MN, USA) was initially performed. The 23 mm balloon was only used as bail-out in veins with a maximal diameter ≤20 mm when PV occlusion could not be obtained. Total ablation duration for the right superior PV was limited to 180s to prevent phrenic nerve palsy. Time-to-isolation was defined as the time from the start of ablation to the disappearance of PV potentials, registered with a 20 mm intraluminal circumferential mapping catheter (Achieve, Medtronic, Minneapolis, MN). If time-to-isolation was not achieved within 90s, ablation was aborted (‘unsuccessful ablation’) and the balloon repositioned. If time-to-isolation could not be determined, time- to-isolation was set to 90s to calculate ablation duration. Thirty minutes after ablation, PV isolation was confirmed and adenosine was infused in order to identify DC. Initial adenosine dose was 18 mg and increased to a maximum of 30 mg to obtain ≥ 1 sinus beat with blocked AV-conduction. In case of DC, a maximum of 2 additional ablations with a fixed 240s duration were performed to abolish DC. During ablation of the right veins, absence of phrenic nerve palsy was confirmed by pacing the phrenic nerve from the superior caval vein at 20mA/2ms with manual verification of diaphragmatic movement. A nasal temperature probe (Sensitherm, St. Jude Medical, Saint Paul, MN, USA) was used to monitor endoluminal esophageal temperature. Ablation was discontinued immediately (“aborted ablation”) using the “double-stop technique” if a reduced diaphragmatic movement or an esophageal temperature <18 °C was reached. Repeated ablations were always performed by point-by-point ablation using a Lasso and Thermocool Smarttouch SF Catheter (CARTO, Biosense Webster Inc., Diamand Bar, CA, USA) or the Advisor circular mapping and Tacticath catheters (Ensite, Abbott, St. Paul, MN, USA). 6.2.3 Follow-up Patients were followed 3, 6 and 12 months after ablation with a 24h Holter and exercise test. AAD were restarted after the ablation and maintained until the first follow-up at 3 months after ablation. Success was defined as the absence of any recording of AF/Atrial tachycardia on ECG or recording of >30s on a 24h Holter registration off AAD after a blanking period of 3 months.