T. J. Hund, N. F. Otani, and Y. Rudy, The dynamics of action potential head-tail interaction during reentry in cardiac tissue: Ionic mechanisms, American Journal of Physiology (Heart and Circulatory Physiology ) 279, H1869-H1879 (2000).
In a sufficiently short reentry pathway, the excitation wavefront (head) propagates into tissue which is partially refractory (tail) from the previous action potential (AP). We incorporate a detailed mathematical model of the ventricular myocyte into a one-dimensional closed pathway to investigate effects of head-tail interaction and ion accumulation on the dynamics of reentry. Results: (1) A high degree of head-tail interaction produces oscillations in AP properties. (2) Ca2+ transient oscillations are in phase with AP duration (APD) oscillations. (3) As the wavefront propagates around the pathway, AP properties undergo periodic oscillations which produce complicated oscillations at a single site. (4) Depending on the degree of head-tail interaction, [Na+]i accumulation either stabilizes reentry or increases the CL oscillations which promote termination of reentry.