Hopf bifurcation and chaos

Biphasic APD Restitution

and Chaos

(Click inside the applet to start)

This is the same principle as in the previous applet. The only difference is that instead of a mono-phasic APD restitution we have a bi-phasic APD restitution. This kind of restitution has been known to occur in some cases when measuring the APD restitution. However, it is not completely known what causes the increase in APD at small DI's. Nevertheless, chaos can be produced with periodic passing at high frequencies.

In this applet, one can see the transition from stable to periodic doubling to chaos and to conduction block as one changes the period of stimulation. Further reading on biphasic APD restitutions and chaos can be found in PRL Vol 78 1387-1390, 1997 by Z. Qu and J.N. Weiss and A. Garfinkel.