Methods
We included n=48 patients with PAF that were scheduled for PVI. We used the QDot catheter (Biosense Webster) in all patients with a temperature controlled HPSD ablation mode with 90 watts for 4 seconds. All patients underwent point-by-point cirumferential PVI. If focal reconnection occurred after repeat ablation with 90watts/4 seconds (QModePlus), the ablation mode was changed to 50watts for 15 seconds (QMode). After PVI, all veins were checked with Adenosine for dormant conduction. In n=23 patients cerebral MRI was performed to detect silent cerebral lesions.
In addition, periprocedural complications and biophysical characteristics were analysed.
All patients underwent contrast enhanced cardiac computertomography for intracardiac thrombus exclusion and cardiac segmentation <24h prior to ablation. If intracardiac thrombus could not be excluded or contraindications for contrast agent admission existed, a transoesophageal echocardiogram (TEE) was performed. All ablations where performed on uninterrupted anticoagulation using direct oral anticoagulants or vitamin K antagonists with an International Normalized Ratio (INR) between 2-3. Heparin was administered to gain an ACT >300 seconds during the procedure. The electrophysiological study was performed under conscious sedation with Propofol, Midazolam and Fentanyl. All patients underwent single transseptal puncture with double access to the left atrium with a steerable 11.7F sheath. Thereafter, 3D mapping of the LA was obtained using the CARTO 3 System with the LASSO Catheter (Biosense Webster, Inc.). In all patients an antral circumferential PVI was performed using a point by point ablation technique. The primary ablation mode was the temperature controlled QMode Plus with 90watts for 4 seconds for both the anterior and posterior portion of PVs. Catheter irrigation was set to 8ml/min, contact force was aimed to be higher than 5g. The cut off temperature for down titration of power was set to 60 degrees on the hottest surface thermocouple. A mandatory pre and post ablation irrigation with 8ml for 3 seconds was applied for each lesion. PVI completion was confirmed using the LASSO mapping catheter placed in the PV ostia after elimination of all PV potentials followed by a 20 minute waiting period. If PVs were not isolated after encircling both ipsilateral veins, additional segmental PVI was performed. If focal reconnection occurred besides repeat ablation with 90watts/4 seconds, the ablation mode was changed to (temperature controlled) 50watts for 15 seconds (QMode). After confirmed PVI, intravenous Adenosine was rapidly administered, with at least 9mg separately for each vein. Adenosine dose was increased if neither third-degree atrioventricular (AV) block nor sinus arrest occurred. In case of PV reconnection, additional segmental ablation was applied at the earliest PV activation time on the level of the circumferential lesion in order to achieve complete PVI under recurrent Adenosine testing.
All patients received a duplex sonography of the access site the day after the procedure. In the duplex scan vascular complications were assessed as described in the consensus report from the Bleeding Academic Research Consortium All patients underwent a local examination to exclude groin infection prior to hospital discharge. Echocardiography to rule out pericardial effusion was performed at the end of the procedure and on the following day. Oral anticoagulation was continued with patients’ standard dose for at least 3 months depending on the calculated CHADS2VASC2 score. Definitions for bleeding and thromboembolic complications were used as described previously by our group (8;9).
N=23 patients underwent post-procedural cerebral MRI within 48h to detect silent cerebral lesions. Cerebral MRI was performed using a 1,5 tesla device (Siemens Healthineers, Erlangen, Germany). In our protocol a T2-weighted axial fluid-attenuated inversion recovery sequence (FLAIR) (TI=2,340ms, TR=9000ms, TE=118ms, slice thickness 5.0 mm, FoV 230 x 187 mm, in-plane resolution: 0.7 x 0.7 mm) and a diffusion-weighted echo-planar imaging sequence (TR=4,700ms, TE 100ms, slice thickness 5.0 mm, FoV 230 x 230 mm, in-plane resolution: 0.9 x 0.9 mm) were used. An additional apparent diffusion coefficient (ADC) maps was obtained.
In addition, Biophysical procedural characteristics were analysed.