Sensitivity of ECG QRS Complexes to His-Purkinje Structure in Computational Heart Models

Area of Science:

• Cardiology
• Computational Biology
• Biophysics

Background:

• Cardiac digital twins (CDTs) are advancing cardiology.
• The His-Purkinje system (HPS) significantly impacts ventricular depolarization and electrocardiogram (ECG) QRS morphology.
• Understanding HPS structural influence on QRS is crucial for CDT accuracy but remains understudied.

Purpose of the Study:

• To quantify the impact of His-Purkinje system structural variations on QRS morphology.
• To identify specific HPS parameters driving QRS variability.
• To assess the clinical relevance of HPS anatomical differences in cardiac modeling.

Main Methods:

• Generated fractal-tree HPS models with systematic variations in nine parameters.
• Assessed effects on ten QRS-related metrics.
• Employed Sobol sensitivity analysis to determine parameter contributions and interactions.

Main Results:

• Minor HPS structural changes generally have minimal impact on individual QRS features.
• Specific parameter combinations can lead to abnormal QRS morphologies and significantly alter wave durations and amplitudes.
• QRS timing variability is mainly influenced by interactions in branch/fascicle angles and branch repulsivity, alongside the number of HPS branches.

Conclusions:

• While certain HPS structural variations can affect QRS morphology and timing, minor anatomical differences in healthy individuals are unlikely to significantly impact CDT fidelity.
• Future CDTs should consider potential HPS variability, especially concerning parameter interactions.
• This study provides insights into HPS structure-function relationships critical for refining cardiac modeling and clinical interpretation.