Sensitivity analysis of ectopic electrical activity in the pulmonary vein myocardium

The pulmonary vein contains a myocardial layer that is capable of generating spontaneous or triggered action potentials. Although the electrophysiological and pharmacological characteristics of the pulmonary vein myocardium have been compiled in various studies, a comprehensive understanding of the spontaneous action potentials generated in the myocardial layer has yet to be presented. Here we integrated the electrophysiological properties of the pulmonary vein myocardial layer using a guinea pig ventricular cell model. Based on the preceding research, which reported that approximately half of the isolated pulmonary vein myocardial layer exhibited spontaneous action potentials and the remaining half was quiescent, we constructed various combinations of the pulmonary vein myocardial models to represent variations of the action potential tracings. As a result, we predicted that the spontaneous action potentials, including burst-like action potentials, are observed with varying currents of the relative densities of Na⁺ (I_Na), L-type Ca²⁺ (I_CaL), inwardly rectifying K⁺ (I_K1), rapid component of delayed rectifying K⁺ (I_Kr), and ACh-activated K⁺ (I_KACh).