Cardiac Beat-to-beat Alternations Driven by Unusual Spiral Waves.
From: National Creative Research Initiative Center for Neuro-Dynamics and Department of Physics, Korea University, Seoul 136-701, Korea.
Proceedings of the National Academy of Sciences of the United States of America
- Publish Date: Jul 2007
- ISSN: 0027-8424
- Volume: 104
- Issue: 28
- Pages: 11639-42
- Medium: Print
- Language: English
- Citation (JAMA): Kim Tae Yun, Woo Sung-Jae, Hwang Seong-Min, et al. Cardiac Beat-to-beat Alternations Driven by Unusual Spiral Waves.. Proc. Natl. Acad. Sci. U.S.A. Jul 2007;104:11639-42
Abstract
Alternans, a beat-to-beat temporal alternation in the sequence of heartbeats, is a known precursor of the development of cardiac fibrillation, leading to sudden cardiac death. The equally important precursor of cardiac arrhythmias is the rotating spiral wave of electro-mechanical activity, or reentry, on the heart tissue. Here, we show that these two seemingly different phenomena can have a remarkable relationship. In well controlled in vitro tissue cultures, isotropic populations of rat ventricular myocytes sustaining a temporal rhythm of alternans can support period-2 oscillatory reentries and vice versa. These reentries bear “line defects” across which the phase of local excitation slips rather abruptly by 2pi, when a full period-2 cycle of alternans completes in 4pi. In other words, the cells belonging to the line defects are period-1 oscillatory, whereas all of the others in the bulk medium are period-2 oscillatory. We also find that a slowly rotating line defect results in a quasi-periodic like oscillation in the bulk medium. Some key features of these phenomena can be well reproduced in computer simulations of a nonlinear reaction-diffusion model.
Mesh Headings (Keywords): Animals, Cells, Cultured, Computer Simulation, Diffusion, Heart Rate, Heart Ventricles, Models, Cardiovascular, Myocardial Contraction, Rats
Check for Full Text / PubMed Unique Identifier (PMID): 17606916
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