Electrical and Calcium Handling Aspects of Alternans: from cell to tissue

Yohannes Shiferaw*

Department of Physics & Astronomy, California State University at Northridge, Northridge, CA, USA

*yohannes.shiferaw@csun.edu

Calcium release in cardiac myocytes can alternate from one beat to the next in a large-small-large sequence referred to as calcium alternans. Imaging of subcellular calcium within cells reveals that calcium alternans can also become spatially out-of-phase, when one part of the cell alternates in a large-small-large sequence while a different part alternates in a small-large-small sequence, a phenomenon known as spatially discordant alternans. It is generally believed that the presence of spatially discordant alternans is arrhythmogenic as it provides a dynamical mechanism for the formation of spatial heterogeneities in the heart. In this talk I will review of our recent theoretical, and experimental, work on calcium and voltage alternans in cardiac myocytes and tissue. I will describe the nonlinear dynamics of voltage and calcium at the single cell level, and describe the spatiotemporal properties of this phenomenon on the tissue scale.

References:

*Aistrup G, *Shiferaw Y, Kapur S, Kadish AH, Wasserstrom A. (*shared first authorship) Mechanisms underlying the formation and dynamics of subcellular calcium alternans in the intact heart. Circ. Res. 104: 639-649, 2009

*Sato D, *Shiferaw Y, Garfinkel A, Weiss JN, Qu Z, Karma A. (*shared first authorship) Spatially discordant alternans in cardiac tissue: role of calcium cycling. Circ Res. 99: 520-527, 2006

Shiferaw Y, Sato D, Karma A. Subcellular Turing instability mediated by voltage and calcium diffusion in cardiac cells. Proc Natl Acad Sci USA. 103: 5670-5675, 2006.