Major findings
We reported the first randomized controlled trial, which had investigated the EVA site distribution and compared the ablation effectiveness between the supravalvular strategy and the subvalvular strategy in patients with idiopathic monomorphic RVOT-type VAs. Half of the EVA sites were above the PVs, and most were within 10mm above PVVJ. The two strategies did not differ in the IA success rates, ablation applications, complications, and long-term VA recurrence. However, the EVA site was an essential characteristic to determine the ablation effectiveness of the two strategies. Ipsilateral IA remarkably increased the success rate and reduced ablation applications.