Skeletal muscle grids for assessing current distributions from defibrillation shocks

Area of Science:

• Computational Electrophysiology
• Biomedical Engineering
• Medical Device Simulation

Background:

• Accurate modeling of defibrillation shocks is crucial for device efficacy.
• Skeletal muscle's anisotropic properties significantly influence current distribution.
• Previous models often simplified the complex three-dimensional torso geometry.

Purpose of the Study:

• To assess current distributions from defibrillation shocks using structured and unstructured grids.
• To compare the accuracy and efficiency of finite-element and finite-difference methods.
• To re-evaluate experimental data regarding current shunting by anisotropic skeletal muscle.

Main Methods:

• Utilized structured and unstructured grid representations of a torso model.
• Employed finite-element solutions on unstructured grids (400,000 and 65,000 elements).
• Compared results with finite-difference solutions on a structured grid.

Main Results:

• Finite-element solutions on unstructured grids achieved comparable current distributions to structured grids.
• A coarser unstructured grid (65,000 elements) yielded results within 5% of finer grids.
• One-dimensional models overestimated current shunting by anisotropic skeletal muscle.

Conclusions:

• Unstructured grids are effective for modeling defibrillation current distributions.
• The study challenges previous interpretations of experimental data on current shunting.
• Anisotropic skeletal muscle shunts approximately 55% of defibrillation current, not over 80%.