Circumferential Pulmonary Vein Isolation Plus Low-Voltage Area Modification in Persistent Atrial Fibrillation: The STABLE-SR-II Trial

Background: Benefits of adjunctive ablation strategies beyond circumferential pulmonary vein isolation (CPVI) are uncertain in patients with persistent atrial fibrillation (PeAF).

Objectives: This study sought to compare clinical outcomes of CPVI plus low-voltage area (LVA) modification during STABLE-SR (SubsTrate ABlation in the LEft Atrium during Sinus Rhythm) vs circumferential pulmonary vein isolation (CPVI) alone in patients with PeAF.

Methods: From March 2018 to August 2019, 300 patients with PeAF who underwent de novo ablation were recruited and prospectively randomized to either STABLE-SR group (n = 150) or CPVI alone (n = 150) group. In the STABLE-SR group, after CPVI, high-density voltage mapping of left atrium (LA) was performed during sinus rhythm, and additive ablation targeted LVA and complex electrograms, if any were present. All the ablations were titrated by ablation index. The primary endpoint was freedom from documented atrial arrhythmias lasting for ≥30 s without the use of antiarrhythmic drugs, after a single ablation procedure and blanking period of 3 months.

Results: After 18 months, atrial-arrhythmia-free survival did not differ significantly between STABLE-SR group and CPVI alone group (67.2% vs 67.4%; HR: 0.89; 95% CI: 0.55-1.36; P = 0.52). Only around one-half of the patients (50.2%) had abnormal LA substrate with a medium LVA burden of 4.6% (2.1%-9.5%). However, the success rate differs dramatically between patients with normal vs abnormal LA substrate (84.8% vs 60.9%; P < 0.001).

Conclusions: Additional LVA ablation did not improve successful rates of CPVI in this PeAF cohort, of whom one-half had normal LA substrate. Voltage map could identify patients with PeAF with normal LA substrate who can achieve excellent rhythm control with CPVI alone. (CPVI Alone Versus CPVI Plus Electrophysiological Substrate Ablation in the LA During SR for the Treatment of Non-PAF [STABLE-SR_II]; NCT03448562).