2.2 Inclusion and exclusion criteria
Two reviewers (C-CF and J-W) screened and identified studies that met the following inclusion criteria: (1) patients with drug-refractory symptomatic AF who accepted radiofrequency ablation; (2) wide-area circumferential ablation (WACA) for PVI applied using irrigated-tip catheters; (3) patients undergoing treatment using CA for the first time; (4) comparison between HPSD and LPLD approaches; (5) sample size ≥20; and (6) studies needed to provide at least one of the reliable information with regard procedure outcomes, complications, first-pass PVI, acute PVs reconnection, and follow-up in both groups. The exclusion criteria were as follows: (1) an equivocal study design or group allocation; and (2) conference abstracts, case reports, case series studies, editorials, review articles, or non-English language articles.