DATA SUPPLEMENT 1D mathematical model of the atrioventricular node including AN, N and NH cells

Models of AN, N and NH action potentials Models were developed for the rabbit, because of the relative plethora of experimental data for this species. Hodgkin-Huxley type models were developed, because there are insufficient experimental data for the development of Markov-type models. The models are a nonlinear dynamic system of 26 simultaneous ordinary differential equations. Cell capacitance Munk et al.(1) showed that the cell capacitance (Cm) of rod-shaped atrioventricular node (AVN) cells with an AN-like action potential configuration is larger (~41 pF) than that of ovoid AVN cells with N- or NH-like action potential configurations (~29 pF). Ren et al. (2) reported that the Cm of AN, N and NH cells to be ~49, ~26 and ~35 pF, respectively. We assumed Cm to be 40 pF for AN and NH cells and 29 pF for an N cell. Ionic currents As shown in Table S2, membrane potential was calculated from the sum of ten ionic currents: Na+ current (INa), L-type Ca2+ current (ICa,L), transient outward K+ current (Ito), rapid delayed rectifier K+ current (IK,r), hyperpolarization-activated current (If), sustained inward curren