Computationally efficient model of myocardial electromechanics for multiscale simulations.

Area of Science:

• Computational Biology
• Biophysics
• Cardiovascular Physiology

Background:

• Understanding myocardial electromechanics is crucial for diagnosing and treating cardiac conditions.
• Existing models often lack integrated electrophysiology, mechanics, and feedback mechanisms.

Purpose of the Study:

• To develop a unified and simplified model of myocardial electromechanics.
• To incorporate mechano-calcium and mechano-electrical feedbacks, including strain-dependent action potential propagation.
• To enable multiscale simulations of the human heart and investigate the impact of mechanics on arrhythmias.

Main Methods:

• Combined and simplified existing models of cardiac electrophysiology, excitation-contraction coupling, and mechanics.
• Incorporated mechano-calcium and mechano-electrical feedback loops.
• Reduced model stiffness for efficient numerical integration.

Main Results:

• The model accurately reproduces changes in twitch amplitude and Ca2+ transients with varying muscle strain.
• It captures the Bowditch effect and alterations in twitch characteristics with changing interstimulus intervals.
• Demonstrated accelerated relaxation at high stimulation frequencies.

Conclusions:

• The developed model offers a computationally efficient tool for simulating myocardial electromechanics.
• It provides a platform for studying the intricate interplay between cardiac mechanics and electrophysiological phenomena like arrhythmias.
• Facilitates multiscale simulations for a comprehensive understanding of the human heart's function.