Dynamic origin of spatially discordant alternans in cardiac tissue

Hideki Hayashi, Yohannes Shiferaw, Daisuke Sato, Motoki Nihei, Shien Fong Lin, Peng Sheng Chen, Alan Garfinkel, James N. Weiss, Zhilin Qu

Research output: Contribution to journalArticle

73 Scopus citations

Abstract

Alternans, a condition in which there is a beat-to-beat alternation in the electromechanical response of a periodically stimulated cardiac cell, has been linked to the genesis of life-threatening ventricular arrhythmias. Optical mapping of membrane voltage (Vm) and intracellular calcium (Ca i) on the surface of animal hearts reveals complex spatial patterns of alternans. In particular, spatially discordant alternans has been observed in which regions with a large-small-large action potential duration (APD) alternate out-of-phase adjacent to regions of small-large-small APD. However, the underlying mechanisms that lead to the initiation of discordant alternans and govern its spatiotemporal properties are not well understood. Using mathematical modeling, we show that dynamic changes in the spatial distribution of discordant alternans can be used to pinpoint the underlying mechanisms. Optical mapping of Vm and Cai in paced rabbit hearts revealed that spatially discordant alternans induced by rapid pacing exhibits properties consistent with a purely dynamical mechanism as shown in theoretical studies. Our results support the viewpoint that spatially discordant alternans in the heart can be formed via a dynamical pattern formation process which does not require tissue heterogeneity.

Original languageEnglish (US)
Pages (from-to)448-460
Number of pages13
JournalBiophysical Journal
Volume92
Issue number2
DOIs
StatePublished - Jan 2007
Externally publishedYes

ASJC Scopus subject areas

  • Biophysics

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    Hayashi, H., Shiferaw, Y., Sato, D., Nihei, M., Lin, S. F., Chen, P. S., Garfinkel, A., Weiss, J. N., & Qu, Z. (2007). Dynamic origin of spatially discordant alternans in cardiac tissue. Biophysical Journal, 92(2), 448-460. https://doi.org/10.1529/biophysj.106.091009