Study Population
24 consecutive patients post cardiac surgery who were referred to our institution for AT ablation were enrolled prospectively between June 2018 and November 2019. All cases were performed under conscious sedation with continuous intravenous fentanyl. All patients provided written informed content to participate in the study, which was approved by the institutional ethics committee.Electrophysiological Study
All antiarrhythmic drugs were discontinued for at least five half-lives, except for amiodarone, which was stopped at least two weeks before the procedure. Transesophageal echocardiography was performed to exclude the presence of thrombus in left atrial appendage prior to the procedure. Electrophysiology study was performed under conscious sedation and local anesthesia. Twelve-lead surface electrocardiograms (ECG) (filtered 0.05-100Hz) and bipolar intracardiac electrograms (filtered 30-250Hz, sweep speed 100 mm/second) were amplified and displayed on a computer-based digital amplifier/recorder system (Bard Electrophysiology, Lowell, MA, USA).
Following vascular access, a 6F quadripolar electrode was placed in the right ventricular apex, and a 6F decapolar catheter was positioned in the coronary sinus via the left femoral vein. One 8.5F long sheath was advanced into the right atrium through the right femoral vein. A transseptal puncture was performed in the patients with AT originating from left atrium. Regular doses of heparin were administered to maintain an activated clotting time of 300-350 seconds throughout the whole procedure.