Fehmi Keçe

Chapter 3 76 3.2 Methods 3.2.1 Study Population Consecutive patients referred for a first ablation of paroxysmal, drug-refractory atrial fibrillation (AF) between March 2015 and December 2016 were included and 1:1 randomized to PVI using the PVAC-Gold (n=35) or Thermocool catheter (Navistar Thermocool, Biosense Webster, Diamond Bar, CA, USA), n=35). Twenty patients with AF ( age and education matched ) not undergoing ablation served as a reference group for neuropsychological testing (baseline and 3 months). Patients with prior AF ablation, persistent AF, contra-indications for MRI and/or the inability to perform neuropsychological testing were excluded. To avoid bias based on different anticoagulant drugs, we chose to start only Vitamin K antagonists in all patients. Patients were kept on vitamin K antagonists from at least 2 months before until 3 months after the procedure For their anticoagulant control, all patients were monitored by the regional anticoagulation clinic. Because of the high expertise and structured protocols followed in these clinics, little deviation from the therapeutic INR range is normally observed. All anticoagulation clinics in the Netherlands follow, in fact, the guidelines of the Dutch Federation of Anticoagulation Clinics, which are published in “Kunst van het doseren”(10) and are updated regularly. Data collection was performed using our electronic patient information system (EPD-Vision). All patients gave written informed consent before study entry. The study was approved by the institutional ethical review board and registered at clinicaltrials.gov (NCT01361295). 3.2.2 Ablation Pre-ablation Phase: Ablation was performed under continued vitamin K antagonist therapy with a targeted peri-procedural international normalized ratio (INR) of 2.0-3.0. Patients were treated under deep sedation using propofol/remifentanil or conscious sedation using midazolam/fentanyl. After venous access, a dose of 5000 IU of heparin was administered. Single (PVAC-Gold) or double transseptal access (Thermocool) were obtained with the needle introduced using the stylet and under intracardiac echocardiography guidance. Mapping of the left atrium (Thermocool) and pulmonary venography (both groups) was performed. ACT was checked every 30 min after transseptal access and maintain >350 s. Energy delivery was not commenced before ACT was >350 s. Ablation Phase : Only ablation lesions aiming at PVI were allowed. PVAC-Gold catheter: Duty cycled RF energy applications of 60s (Genius Generator software version 15.1 Medtronic Inc., Minneapolis, MN, USA) were delivered in a bipolar: unipolar ratio of either 4:1 (10 W) or 2:1 (8 W) until PVI was achieved. Pulmonary vein isolation was mainly (99%) performed in 2:1 energy mode. This