Identification of local atrial conduction heterogeneities using high-density conduction velocity estimation

Area of Science:

• Electrophysiology
• Cardiac Arrhythmias
• Cardiovascular Research

Background:

• Accurate measurement of intra-atrial conduction velocity (CV) is crucial for identifying arrhythmogenic areas.
• Existing methods like finite differences (FiD) and polynomial surface fitting (PSF) may obscure local conduction heterogeneities.
• The optimal technique for high-density CV estimation and heterogeneity analysis remains undetermined.

Purpose of the Study:

• To identify the most suitable methodology for unraveling local conduction heterogeneities using high-density CV estimation.
• To quantify intra-atrial differences in CV.
• To localize areas of CV slowing associated with paroxysmal atrial fibrillation (PAF).

Main Methods:

• Intra-operative epicardial mapping (>5000 sites) was performed during sinus rhythm in 412 patients with or without PAF.
• Conduction velocity was estimated using discrete velocity vectors (DVV), polynomial surface fitting (PSF), and finite differences (FiD) techniques.
• Analysis focused on the right atrium, left atrium, and Bachmann's bundle (BB).

Main Results:

• Median CV estimates were similar across techniques: DVV (90.0 cm/s), PSF (92.0 cm/s), and FiD (89.4 cm/s).
• The DVV technique detected smaller CV magnitudes compared to PSF, indicating it is more sensitive to local variations.
• A significantly lower CV at the Bachmann's bundle was observed in PAF patients compared to non-PAF patients (79.1 vs. 88.3 cm/s; P < 0.001) using DVV.

Conclusions:

• The DVV technique is superior for identifying local conduction heterogeneities, as PSF and FiD smooth wavefront propagation.
• Slower wavefront propagation at the Bachmann's bundle during sinus rhythm in PAF patients suggests underlying structural remodeling.
• DVV is a valuable tool for understanding atrial electrophysiology and identifying targets for arrhythmia management.