Left Atrial Posterior Wall Functional Remodeling in Paroxysmal and Persistent Atrial Fibrillation. A Pilot Study

Area of Science:

• Electrophysiology
• Cardiology
• Medical Imaging

Background:

• The left atrial posterior wall (LAPW) is a key target in atrial fibrillation (AF) ablation.
• Current substrate-guided ablation using structural markers yields inconsistent results.
• Investigating functional markers like posterior wall conduction time (PWCT) is crucial for improving ablation efficacy.

Purpose of the Study:

• To evaluate PWCT as a novel functional marker of LAPW remodeling in AF patients.
• To assess the relationship between PWCT and structural markers of remodeling.
• To determine the potential of PWCT in guiding personalized AF ablation.

Main Methods:

• A pilot study included 40 patients undergoing first-time AF ablation (20 paroxysmal, 20 persistent).
• Electrophysiological mapping assessed AF cycle length (AF CL), linear conduction, conduction area (PWCA), and PWCT at various pacing cycle lengths.
• Major decremental PWCT was defined as a ≥17% increase at 400 ms pacing compared to 600 ms.

Main Results:

• Persistent AF patients exhibited larger posterior wall area (PWA) and low voltage area (LVA), and shorter left atrial appendage AF CLs compared to paroxysmal AF patients.
• PWCT was numerically longer in persistent AF, with major ΔPWCT observed exclusively in 6 persistent AF patients.
• In the major ΔPWCT subgroup, PWCA reduction occurred with decremental pacing, independent of PWA size, LVA, or AF CL.

Conclusions:

• PWCT may serve as a novel functional biomarker for LAPW remodeling, distinct from structural changes.
• PWCT has the potential to identify patients who could benefit from targeted LAPW ablation.
• Further research is necessary to validate PWCT for personalized AF ablation strategies.