A simulation of cardiac action currents having curl

A digital simulation of a two-dimensional cardiac slice has been performed. It is stimulated at the center and an action potential propagates outward. An anisotropic bidomain model is used in which fast sodium physiology connects the intracellular and extracellular domains. For cases in which the inner asymmetry (expressed as longitudinal versus transverse electrical conductivity) is greater than the outer asymmetry, a current flow pattern is observed for which there is nonzero curl. Such a result explains recent observations of nonzero B/sub z/ magnetic field detected above a slab of tissue in the x-y plane. The current loop producing this field consists of outer domain current in the longitudinal direction flowing around in space and returning at the AP location in the transverse direction in the outer domain and then completing the loop in the longitudinal direction by passing distally through the AP in the inner domain where resistance is extremely low.<<ETX>>

[1]  J P Wikswo,et al.  Possible sources of new information in the magnetocardiogram. , 1982, Journal of theoretical biology.

[2]  Latencies in action potential stimulation in a two-dimensional bidomain: A numerical simulation , 1991 .

[3]  Computer simulations of cardiac action potentials in two dimensions , 1988, Brain Research Bulletin.

[4]  S. Knisley,et al.  Interstitial potential during propagation in bathed ventricular muscle. , 1991, Biophysical journal.

[5]  J.P. Barach.  Simulation of action potentials in a one-dimensional bidomain , 1988, IEEE Transactions on Biomedical Engineering.

[6]  R. W. Joyner,et al.  Propagation through electrically coupled cells. Effects of a resistive barrier. , 1984, Biophysical journal.

[7]  R. Barr,et al.  Current flow patterns in two-dimensional anisotropic bisyncytia with normal and extreme conductivities. , 1984, Biophysical journal.

[8]  N. G. Sepulveda,et al.  Electric and magnetic fields from two-dimensional anisotropic bisyncytia. , 1987, Biophysical journal.

[9]  E. Niebur,et al.  Numerical implementation of sealed-end boundary conditions in cable theory , 1991, IEEE Transactions on Biomedical Engineering.

[10]  C. Henriquez,et al.  Simulation of propagation along a cylindrical bundle of cardiac tissue. II. Results of simulation , 1990, IEEE Transactions on Biomedical Engineering.

[11]  D DiFrancesco,et al.  A model of cardiac electrical activity incorporating ionic pumps and concentration changes. , 1985, Philosophical transactions of the Royal Society of London. Series B, Biological sciences.

[12]  C. Henriquez,et al.  Simulation of propagation along a cylindrical bundle of cardiac tissue. I. Mathematical formulation , 1990, IEEE Transactions on Biomedical Engineering.

[13]  N. G. Sepulveda,et al.  Current injection into a two-dimensional anisotropic bidomain. , 1989, Biophysical journal.

[14]  J. P. Barach.  A computer simulation routine for cardiac action potentials , 1987 .

[15]  John P. Barach.  A Method of Calculation for Simulation of Action Potentials , 1986, IEEE Transactions on Biomedical Engineering.

[16]  D. Roden,et al.  Virtual cathode effects during stimulation of cardiac muscle. Two-dimensional in vivo experiments. , 1991, Circulation research.

[17]  F A Roberge,et al.  Reconstruction of Propagated Electrical Activity with a Two‐Dimensional Model of Anisotropic Heart Muscle , 1986, Circulation research.

[18]  F A Roberge,et al.  Revised formulation of the Hodgkin-Huxley representation of the sodium current in cardiac cells. , 1987, Computers and biomedical research, an international journal.

[19]  R. Barr,et al.  Propagation of excitation in idealized anisotropic two-dimensional tissue. , 1984, Biophysical journal.

[20]  J W Moore,et al.  A numerical method to model excitable cells. , 1978, Biophysical journal.

[21]  B. Roth,et al.  Magnetic Measurements of Action Currents in a Single Nerve Axon: A Core-Conductor Model , 1985, IEEE Transactions on Biomedical Engineering.

[22]  F. V. Van Capelle,et al.  Propagation through electrically coupled cells. How a small SA node drives a large atrium. , 1986, Biophysical journal.