Objectives The first purpose of this paper is to explain the generation mechanism of myocardial resting potential from the perspectives of nonlinear dynamics and physiology. The second objective is to establish a theoretical calculation method for ventricular myocardial material parameters, such as the elastic modulus, Poisson's ratio and shear modulus. Methods The physiological essence of the resting potential is the blocking of mismatched ions by ion channels, which is described by a probability model of fully misaligned arrangements. The calculation of the elastic modulus of ventricular muscle is based on the stress distribution characteristics at the end of diastole and the modified Laplace's law. Results The misaligned-arrangement probability model, the modified Laplace's law of cardiac diastole and the three-dimensional pressure equalization theory of cardiac systole are demonstrated in detail, and the probability model is verified by exhaustive enumeration and Monte Carlo simulation. A theoretical calculation method for the ventricular muscle elastic modulus is established relying solely on echocardiography data instead of costly measurement methods such as magnetic resonance imaging (MRI). The reference range of the radial elastic modulus of human ventricular muscle is calculated, which is of the same order of magnitude as the experimental data of the isolated porcine heart. Limitations The present estimates are obtained under idealized assumptions (linear isotropic elasticity and spherical geometry) and require clinical validation; the method may potentially enable primary screening of ventricular myocardial elasticity, but it cannot replace diagnostic imaging methods such as magnetic resonance imaging.
