A model of stimulus frequency effects on the rabbit atrial myocyte

A mathematical model of the electrophysio-logical responses of the rabbit atrial cell has recently been developed by our group that is based on whole-cell voltage clamp data from enzymatically isolated cardiac myocytes. It is able to simulate (1) the whole-cell voltage clamp data upon which it is based, (2) the frequency-dependent action potential waveshape changes that occur in response to variations in the rate of stimulation, and (3) the modulation of frequency-dependent action potential waveshape changes by acetylcholine. The model also predicts the intracellular [Ca²⁺]i-transient during the action potential and changes that this waveform undergoes as stimulus rate is varied.