Dynamic Atrial Substrate During High-Density Mapping of Paroxysmal and Persistent AF: Implications for Substrate...

Area of Science:

• Electrophysiology
• Cardiac Mapping
• Atrial Fibrillation Research

Background:

• The variability of left atrial (LA) substrate mapping based on pacing cycle length and wave front direction remains poorly understood.
• Current understanding of LA substrate in atrial fibrillation (AF) may be limited by mapping methodology.

Purpose of the Study:

• To investigate the impact of pacing rate and direction on left atrial (LA) substrate characteristics in patients with AF.
• To determine how variations in cycle length and wave front propagation influence electroanatomic mapping of the LA.

Main Methods:

• Electroanatomic LA mapping was performed in 73 AF patients using a multipolar catheter.
• Pacing was conducted from the coronary sinus (CS) at 600 ms and 300 ms, and from the left superior pulmonary vein at 300 ms.
• Bipolar voltage, conduction velocity (CV), and complex signals were analyzed.

Main Results:

• Reduced pacing cycle length (300 ms vs. 600 ms) significantly decreased global LA voltage and CV, while increasing complex signals.
• Left superior pulmonary vein pacing induced regional changes, including lower voltage and CV, and more posterior complex signals compared to CS pacing.
• AF duration and left ventricular ejection fraction were independent predictors of voltage changes.

Conclusions:

• Variations in pacing rate and direction significantly alter LA substrate maps, causing both generalized and regional changes.
• The findings suggest potential limitations of static low-voltage maps in accurately identifying AF ablation targets.
• Dynamic mapping strategies may be necessary for precise AF substrate characterization.