Modifications to the Wilders-Jongma-van Ginneken model of pacemaker electrical activity

The Wilders-Jongsma-van Ginneken single cell model of sinoatrial node electrical activity was found to be unsuitable for simulating autonomic modulation of sinoatrial node rhythm. The equations were modified by reducing the effects of the large sarcoplasmic reticulum calcium store, altering the kinetics of the L-type calcium current, and modifying the activation curve of the hyperpolarizing-activated current i/sub f/. The resulting model was able to reproduce the chronotropic responses of cardiac period to sympathetic and parasympathetic stimulation.