Modeling Action Potential Reversals in Tunicate Hearts

Authors

John W. Cain, Harvard University
Luran He, Harvard University
Lindsay D. Waldrop, Chapman UniversityFollow

Document Type

Article

Publication Date

12-23-2020

Abstract

Tunicates are small invertebrates which possess a unique ability to reverse flow in their hearts. Scientists have debated various theories regarding how and why flow reversals occur. Here we explore the electrophysiological basis for reversals by simulating action potential propagation in an idealized model of the tubelike tunicate heart. Using asymptotic formulas for action potential duration and conduction velocity, we propose tunicate-specific parameters for a two-current ionic model of the action potential. Then, using a kinematic model, we derive analytical criteria for reversals to occur. These criteria inform subsequent numerical simulations of action potential propagation in a fiber paced at both ends. In particular, we explore the role that variability of pacemaker firing rates plays in generating reversals, and we identify various favorable conditions for triggering retrograde propagation. Our analytical framework extends to other species; for instance, it can be used to model competition between the sinoatrial node and abnormal ectopic foci in human heart tissue.

Comments

This article was originally published in Physical Review E, volume 102, in 2020. https://doi.org/10.1103/PhysRevE.102.062421

Recommended Citation

J. W. Cain, L. He, and L. Waldrop, Phys. Rev. E. 102, 06241 (2020). https://doi.org/10.1103/PhysRevE.102.062421

Copyright

American Physical Society