Effects of membrane noise on cardiac excitable model pacemaking activity

Fluctuations of the cardiac pacemaker cell membrane voltage can affect the regularity of the heartbeat. Understanding the effects of stochastic membrane variations on the period of spontaneous activity would help determine the stability and robustness of pacemaker cells. The specific dependency of these effects and the rate of spontaneous activity in presence of a bias parameter were studied in the Luo-Rudy model and a Fitzhugh-Nagumo type model. Important differences between models are found with interesting acceleration or deceleration effects and pauses of activity. These results highlight the need for further evaluation of more realistic ionic model.