Comprehensive chaotic description of heartbeat dynamics using scale index and Lyapunov exponent

Since cardiac system is capable of exhibiting chaotic behaviors, many works have been carried out to study its dynamics. In this paper, based on Grudzi´ nski and Zebrowski’s model, the impacts of external periodic stimuli on cardiac impulses were studied using the scale index and Lyapunov exponent. Obtained results revealed that the scale index can detect special behaviors in the action potential whereas the Lyapunov exponent is not capable of uncovering them. Furthermore, it was found that the non-periodicity of pacemaker rhythms in the presence of external factors is not high, but the restoration of the heart to normal conditions requires medical attentions.