Ultrastructure and cardiac impulse propagation: scaling up from microscopic to macroscopic conduction

Area of Science:

• Cardiovascular Physiology
• Computational Biology
• Biophysics

Background:

• Current cardiac conduction models rely on cable theory, treating heart tissue as a continuous medium.
• These models often overlook microscopic and macroscopic heterogeneities, such as subcellular ion channel distribution and nerve innervation.

Purpose of the Study:

• To review progress in modeling the impact of cardiac ultrastructure on electrical conduction.
• To identify challenges in cardiac modeling and propose methods for multi-scale analysis.

Main Methods:

• Discussion of current modeling approaches for cardiac ultrastructure.
• Analysis of scaling issues from subcellular to whole-heart levels.

Main Results:

• Standard models employing 'coarse graining' neglect critical ultrastructural details.
• Ultrastructural components significantly influence cardiac conduction and arrhythmogenesis, especially in disease.

Conclusions:

• Revisiting cardiac conduction models to include ultrastructural details is essential.
• Future research must bridge subcellular and macroscopic scales to accurately predict electrical propagation and arrhythmias.