Efficacy and Safety of Adjunctive Substrate Modification During Pulmonary Vein Isolation for Atrial Fibrillation: A Meta-Analysis.

BACKGROUND: The efficacy and safety of adjuvant substrate modification (SM; either linear ablation [LA] or complex fractionated atrial electrogram [CFAE] ablation) in addition to pulmonary vein isolation (PVI) for the treatment of symptomatic, drug-refractory atrial fibrillation (AF), have still not been clarified and need further assessment. METHOD: We systematically searched the PubMed, MEDLINE, and Cochrane databases for studies comparing PVI with adjunctive SM versus PVI alone for treatment of drug-refractory AF. RESULTS: Twenty-six (26) studies including 3,409 patients (1,975 PVI + SM; 1,434 PVI alone) were included for further analysis. Atrial fibrillation/atrial tachycardia-free survival of patients with PVI + SM was comparable with that of PVI alone (relative risk [RR], 1.06; 95% confidence interval [CI], 0.98-1.14; p = 0.143). In line with this, the primary clinical outcomes were robust, irrespective of additional LA (RR, 1.07; 95% CI, 0.97-1.18; p = 0.194) or CFAE ablation (RR, 1.04; 95% CI, 0.93-1.16; p = 0.534). Adjuvant SM is associated with longer procedural time (weighted mean difference, 20.72; 95% CI, 10.25-31.20; p = 0.0) and fluoroscopy time (weighted mean difference, 6.66; 95% CI, 1.74-11.58; p = 0.000); surprisingly, it presented similar procedure-related complications as PVI alone during AF catheter ablation (RR, 1.01; 95% CI, 0.68-1.50; p = 0.946). CONCLUSIONS: Adjuvant LA or CFAE ablation do not provide incremental benefit over PVI alone. Although substrate-based ablation markedly prolonged procedural and fluoroscopic duration, there was no evidence of increased risk of procedure-related complications.