Study design
The present study is a prospective single-center open-label randomized
controlled trial. The study design was illustrated in Figure 1. After
activation mapping of RVOT, PSCs and pulmonary artery (PA), the patients
were randomly assigned to initial ablation (IA) with the supravalvular
strategy using the reversed U-curve method and the subvalvular strategy
using the antegrade method. Randomization was performed by tossing a
coin. Ablation attempts were performed with uniformed power of 30w,
duration of 10s, and irrigation rate of 17ml/min. Effective ablation was
defined as suppression of VA by the ablation attempts. Isoproterenol was
administrated to increase the frequency of premature ventricular
contraction if necessary. Once effective ablation was identified,
ablation was continued for 60s~90s. Each ablation
application, including ablation attempts, was counted. Successful
ablation was defined as non-inducibility of the clinical VAs with
isoproterenol elicitation for 30 min. IA success was defined as the
successful ablation within the first three ablation applications by the
assigned strategy. IA failure included the following situations.
Firstly, successful ablation was not achieved with more than three
ablation attempts by the assigned strategy. Secondly, the IA targets and
EVA sites were contralateral to the PVs, and the distance from EVA site
to PVVJ was more than 10mm. Thirdly, the operator had the discretion to
declare IA failure after at least one ablation application for the
patients whose targets and EVA sites were contralateral to the PVs.
Patients with IA failure were managed with the other ablation strategy.