Identification of Atrial Transmural Conduction Inhomogeneity Using Unipolar Electrogram Morphology

Area of Science:

• Electrophysiology
• Cardiac Pathophysiology
• Medical Imaging

Background:

• Structural remodeling is key in atrial fibrillation (AF) pathophysiology.
• Transmural remodeling may cause electrical endo-epicardial asynchrony (EEA).
• EEA areas are potential targets for AF ablation.

Purpose of the Study:

• To investigate if transmural conduction block (T-CB) causes more EEA than single-sided conduction block (SS-CB).
• To identify unipolar potential morphology parameters predictive of SS-CB and T-CB.

Main Methods:

• Simultaneous endo-epicardial mapping in 86 human right atrium patients.
• Analysis of unipolar potential voltages, low-voltage areas, and potential complexity (long double and fractionated potentials: LDPs and FPs).
• Assessment of fractionation duration.

Main Results:

• EEA was primarily influenced by T-CB.
• T-CB areas showed lower potential voltages and more LDPs/FPs than SS-CB areas.
• Epicardial unipolar potential morphology parameters accurately predicted T-CB (AUC = 0.91).

Conclusions:

• T-CB is strongly associated with increased EEA.
• Combining voltage, fractionation, and fractionation duration predicts T-CB.
• T-CB areas may serve as effective targets for AF ablation.