Left atrial multi-site pacing achieves 10x greater AF cycle length prolongation vs. catheter ablation- evidence of non-destructive substrate modification in humans
K Sinha, B J D Doliner, D C Chou, T J C Corvi, P S N Safavi-Naeini, M M J John, L M J Jaworski, D J B Bernard, W B B Bomela, B A C Coppola, R W Werneth, M R RazaviAbstract
Background
Cycle length (CL) prolongation during atrial fibrillation (AF) ablation is a validated marker of substrate modification and procedural success. Conventional thermal ablation, however, typically yields only modest increases (20–40 ms; 10–20%). Left atrial multi-site pacing (LAMSP), delivered via Spatial Resynchronization Therapy (SRT), organizes AF electrically rather than cause tissue destruction. We evaluated whether LAMSP achieves greater AF organization and CL prolongation compared with reported values for catheter ablation.
Methods
Six patients (mean age 60 ± 19 years; mean LAVI 52.2 ± 20.5 ml/m²) with inducible AF underwent LAMSP. Spatially distributed multi-site epicardial electrodes were positioned at the anterior, posterior, and lateral left atrial walls and the right atrium, which was only used as a reference and not for pacing. LAMSP was delivered at optimized minimum pacing periods (MPP 150–193 ms). AF CL was measured at baseline and during therapy; global control was defined as coordinated activation across all electrode sites in all atrial regions with 1:1 correlation to pacing cycle length (CL). Results were compared with published ablation studies reporting CL changes during effective substrate modification.
Results
Baseline AF CL ranged from 145–220 ms. Upon LAMSP initiation, global control was achieved in all patients within 1.5–4 seconds. Mean CL prolongation was 125 ± 52 ms (100–200% increase), with maximal effects (ΔCL 180–200 ms) in patients with moderate atrial remodeling. Even persistent AF cases showed 50–100 ms (25–50%) increases. CL prolongation correlated with global control (r = 0.82; p < 0.01) and predicted AF termination in 4/4 Cohort II patients.
Conclusion
LAMSP induces rapid, substantial AF cycle length prolongation and spatial organization through coordinated spatially distributed multi-site pacing, demonstrating superior efficacy. This form of non-destructive "electrical debulking" may represent a novel, tissue-sparing strategy for durable substrate modification and possible rhythm restoration in AF.