Defining myocardial fiber bundle architecture in atrial digital twins

Area of Science:

• Computational Biology
• Medical Imaging
• Biophysics

Background:

• Accurate myocardial fiber orientation is critical for developing patient-specific atrial digital twins (ADT).
• Current methods for generating atrial fibers in ADT often rely on mathematical models that lack rigorous validation and are limited by specific atrial morphologies.
• Existing semi-automatic approaches struggle with complex bi-atrial geometries and do not fully leverage detailed imaging data.

Purpose of the Study:

• To introduce a novel atrial Laplace-Dirichlet-Rule-Based Method (LDRBM) for precise myofiber orientation prescription and regional annotation in complex bi-atrial morphologies.
• To validate the LDRBM against high-resolution Diffusion-Tensor-Magnetic-Resonance Imaging (DTMRI) data, establishing a new standard for fiber modeling in ADT.

Main Methods:

• Development and application of the atrial Laplace-Dirichlet-Rule-Based Method (LDRBM) for generating detailed myofiber orientations.
• Validation using eight complex bi-atrial geometries derived from sub-millimeter DTMRI human atrial fiber datasets.
• Quantitative comparison of LDRBM-generated fibers with DTMRI ground truth and assessment of resulting electrophysiology (EP) simulation differences.

Main Results:

• The LDRBM successfully recreated DTMRI-derived atrial fiber architectures with high fidelity across diverse bi-atrial morphologies.
• Electrophysiology simulations using LDRBM fibers showed excellent agreement with those derived from DTMRI data.
• The LDRBM demonstrated superior performance compared to existing state-of-the-art fiber modeling techniques.

Conclusions:

• The LDRBM provides an accurate and robust method for prescribing detailed myofiber orientations, essential for physics-based atrial digital twins.
• This methodology establishes a new benchmark for fiber prescription in ADT, improving the accuracy of virtual cardiac models.
• The findings underscore the importance of incorporating precise fiber orientations for reliable electrophysiology simulations and the advancement of personalized cardiac medicine.