Modeling effects of strain-modulated membrane capacitance and conductance of K+ inward rectifier on conduction velocity in cardiac tissue

Mechanical deformation of cardiac myocytes has been shown to alter the conductance of various ion channels and possibly membrane capacitance. Here, we studied the strain-modulation of electrical membrane properties at rest. In particular we studied the conductance of the inward rectifying K⁺ channel (G_K1) and the membrane capacitance (C_m) with respect to cellular electrophysiology and conduction velocity. For this purpose, we applied mathematical models of cardiac myocytes in computational simulations. To explore strain modulation we varied the C_m and G_K1 in the range of ±25% of their original values. Conduction velocity (¿) decreased to 39.7 and 45.7 cm/s with +25% in C_m and G_K1 respectively. A decrease of 25% in C_m and G_K1 caused a respective increased of 57.9 and 48.4 cm/s where 47.0 cm/s was the ¿ using default values. Our study indicates that establishing the relationship between strain and G_K1 as well as strain and C_m at myocyte level will be necessary to understand measured strain-¿ relationships in myocardium.