Model-based analysis of optically mapped epicardial activation patterns and conduction velocity

Area of Science:

• Cardiovascular Physiology
• Biophysics
• Medical Imaging

Background:

• Understanding epicardial conduction is crucial for diagnosing and treating cardiac arrhythmias.
• Current methods for quantifying conduction velocity often lack sufficient spatial resolution or anatomical integration.

Purpose of the Study:

• To develop and validate a novel parametric model-based method for quantifying epicardial conduction patterns and velocity.
• To integrate anatomical and geometric features of the ventricles into the analysis of wave propagation.

Main Methods:

• Utilized optical mapping with voltage-sensitive dye (DI-4-ANEPPS) and a high-speed camera on an isolated Langendorff-perfused rabbit heart.
• Extracted activation maps and interpolated them onto a 3D finite-element model of epicardial geometry and fiber structure.
• Computed conduction velocity vector fields from activation time gradients expressed in parametric coordinates.

Main Results:

• The novel method demonstrated high spatial resolution in quantifying epicardial conduction.
• No significant difference was found between optical mapping and bipolar electrode measurements of activation times.
• The method detected significant decreases in fiber (34%) and cross-fiber (28%) velocities after heptanol administration.

Conclusions:

• The combination of optical mapping and 3D geometric modeling offers a powerful new tool for studying cardiac electrophysiology.
• This approach enables high-resolution quantification of wave-front propagation relative to cardiac anatomy.
• The method is sensitive to pharmacological interventions affecting myocardial conduction properties.