Ablation procedure
AF ablation strategy of our center has been described previously.9-10 Briefly, all patients underwent transesophageal echocardiography to exclude left atrial thrombosis. All antiarrhythmic drugs except amiodarone were stopped for at least five half-lives before the procedure. The procedures were guided by CARTO system under conscious sedation. A continuous irrigated radiofrequency ablation (Navi-Star Thermocool, or Thermocool-Smart-touch Biosenes Webster, USA) was performed along each pulmonary vein antrum in order to encircle the ipsilateral pulmonary veins (maximum power: 35 W, infusion rate: 17 ml/min). Procedural end-points were electrical isolation of all pulmonary veins in the patients with paroxysmal AF. In the patients with persistent AF, left atrial roofline, mitral isthmus and cavotricuspid isthmus were routinely targeted. Cardioversion was performed if sinus rhythm was not achieved after circle and line ablation. Additional ablation was applied, if needed, to achieve pulmonary veins isolation and linear block in sinus rhythm.
In repeat procedure, pulmonary veins isolation was achieved again if recovered pulmonary veins conduction gaps existed. Conduction recovery across ablation line was also ablated to achieve line block in those who received linear ablation. Entrainment mapping and 3D activation mapping were applied to identify the mechanism of organized atrial tachycardia. The earliest activation site was ablated for focal atrial tachycardia and the critical isthmus was ablated for macro-reentry atrial tachycardia, respectively. Additional ablation of superior vena cava, complex fractionated atrial electrograms were performed as the operator’s discretion. The endpoints of the repeat procedure included pulmonary veins isolation, bidirectional linear block if targeted and non-inducibility of atrial tachyarrhythmias by burst pacing at minimum interval with1:1 atrial capture.