Cycle length oscillations and reentrant rhythms

The author explores the behavior of reentry that occurs in an adjustable tricuspid ring, where the size of the ring is adjusted by a delay time. When the conduction velocity of reentry is plotted against the ring size, one can locate a phase transition from which unsustained reentry emerges from sustained reentry. This transition is smooth rather than abrupt. In this region, cycle length oscillates with an interesting pattern, which becomes complex as the strength of the sodium current increases.