Atrial fibrillation (AF) catheter ablation is commonly performed using pulmonary vein isolation (PVI). Conventional PVI is achieved by creating a continuous circumferential antral lesion set, but this may require extensive lesion delivery on the posterior left atrium where the esophagus is adjacent. Voltage mapping can characterize regional atrial signal amplitude, and a stepwise strategy that prioritizes higher-voltage sites along a planned antral path may reduce unnecessary lesion delivery while still achieving acute isolation. This randomized trial compares a voltage-guided stepwise PVI strategy with a conventional circumferential antral PVI strategy in patients undergoing first-time AF ablation.
Participants are randomized 1:1 to one of two PVI strategies. All procedures are performed using a standardized workflow for left atrial mapping and PVI verification. Acute PVI is confirmed by elimination or dissociation of pulmonary vein potentials. Durability of isolation is assessed during the index procedure using adenosine testing for dormant conduction, and trigger provocation is performed per protocol. If isolation is incomplete, additional ablation guided by residual electrical potentials is permitted in both groups to achieve the procedural endpoint.
In the voltage-guided stepwise PVI group, ablation is delivered point-by-point along a predefined antral line using a prespecified stepwise algorithm. Lesion delivery is initiated at sites meeting a high bipolar voltage threshold and expanded stepwise to include progressively lower-voltage sites only as needed until PVI is achieved. If isolation cannot be achieved at the minimum voltage threshold, previously ablated points may be connected to complete a continuous line, and adjunctive ablation (e.g., carina or residual potential-guided ablation) may be performed when necessary.
In the conventional circumferential antral PVI group, operators create a continuous circumferential antral lesion set around the pulmonary veins using the standard approach. Additional potential-guided ablation is allowed when needed to achieve PVI. Voltage information is not used to guide lesion distribution in this group during the procedure.
To systematically assess esophageal safety, diagnostic esophagoscopy is performed between post-procedure day 1 and day 3 in all participants using prespecified criteria for esophageal thermal injury. Follow-up is conducted at scheduled intervals with electrocardiography and ambulatory rhythm monitoring per protocol to document arrhythmia outcomes. A post-ablation blanking period is applied for clinical outcome assessment.
Analyses are performed primarily on an intention-to-treat basis. In addition to the prespecified efficacy and safety comparisons between treatment groups, exploratory analyses evaluate relationships between local voltage characteristics and the voltage threshold required for isolation, including variation by pulmonary vein location and AF phenotype.
