Methods Inf Med 2000; 39(02): 118-121
DOI: 10.1055/s-0038-1634285
Original Article
Schattauer GmbH

Bifurcation in a Simple Model of the Cardiovascular System

S. Eyal
1  School of Physics and Astronomy, University of Tel-Aviv, Tel-Aviv, Israel
,
S. Akselrod
1  School of Physics and Astronomy, University of Tel-Aviv, Tel-Aviv, Israel
› Author Affiliations
Further Information

Publication History

Publication Date:
07 February 2018 (online)

Abstract:

A simple nonlinear beat-to-beat model of the human cardiovascular system has been studied. The model, introduced by DeBoer et al. was a simplified linearized version. We present a modified model which allows to investigate the nonlinear dynamics of the cardiovascular system. We found that an increase in the -sympathetic gain, via a Hopf bifurcation, leads to sustained oscillations both in heart rate and blood pressure variables at about 0.1 Hz (Mayer waves). Similar oscillations were observed when increasing the -sympathetic gain or decreasing the vagal gain. Further changes of the gains, even beyond reasonable physiological values, did not reveal another bifurcation. The dynamics observed were thus either fixed point or limit cycle. Introducing respiration into the model showed entrainment between the respiration frequency and the Mayer waves.