Characterizing His-Purkinje system signals observed at the body surface. A model study

Area of Science:

• Computational electrophysiology
• Cardiac modeling
• Biophysics

Background:

• Accurate modeling of the cardiac conduction system is crucial for understanding electrocardiograms (ECGs) and electrophysiological phenomena.
• Existing models may not fully capture the complex geometry and electrical activity of the His-Purkinje system (HPS).

Purpose of the Study:

• To develop and validate a computer model of the human His-Purkinje system (HPS).
• To use the model to calculate electrocardiograms (ECGs), isofield potentials, and magnetic maps.
• To investigate the contribution of atrial repolarization to the PR segment ramp pattern in ECGs.

Main Methods:

• Development of a computer model of the His-Purkinje system (HPS) based on human geometry.
• Integration of the HPS model with an atrial model and an inhomogeneous torso model.
• Calculation of electrocardiograms (ECGs), isofield potentials, and magnetic maps using the integrated model.

Main Results:

• The model calculated a maximum electric potential for His bundle (HB) activity of 0.6 microV.
• Simulated ECGs incorporating atrial and HPS activity suggest atrial repolarization contributes to the PR segment ramp pattern.
• Simulated isofield distributions highlight key features for serial HPS mapping, including the onset of HB activity and changes in extrema location and magnitude.

Conclusions:

• The developed HPS computer model provides a valuable tool for simulating cardiac electrical activity and generating electrophysiological maps.
• The model elucidates the role of atrial repolarization in ECG waveform characteristics.
• Recommendations are provided for interpreting serial HPS maps based on simulated isofield distributions.