Trabecular Architecture Determines Impulse Propagation Through the Early Embryonic Mouse Heart

Area of Science:

• Cardiovascular Development
• Cardiac Electrophysiology
• Computational Biology

Background:

• Embryonic ventricular cardiomyocytes are uniform, unlike the adult heart's specialized conduction system.
• The role of embryonic cardiac structure in impulse propagation is not fully understood.

Purpose of the Study:

• To investigate if embryonic trabecular geometry dictates cardiac impulse conduction pathways.
• To compare simulated and experimental cardiac activation patterns.

Main Methods:

• 3D confocal microscopy of mouse embryonic hearts (ED9.5-ED14.5).
• Analysis of trabecular orientation using homogenized tensors.
• Simulation of impulse propagation and comparison with optical mapping experiments.

Main Results:

• Simulated impulse propagation matched experimental epicardial activation maps.
• Trabecular geometry predicted early epicardial breakthrough points.
• Ectopic activation patterns were consistent between simulations and experiments.

Conclusions:

• Embryonic trabecular network geometry is sufficient to explain cardiac impulse propagation.
• This geometric influence precedes the development of a distinct conduction system.