Modeling of heart excitation patterns caused by a local inhomogeneity.

We simulate wave propagation in the whole heart containing a local inhomogeneity whose properties mimic some properties of cardiac tissue during the acute phase of infarction. The dynamics of cardiac tissue is described by a FitzHugh-Nagumo (FHN) model. We show that two or several short-period stimulations of the heart lead to the development of a three-dimensional vortex ring, which is a temporal source of high frequency waves. The vortex ring is located near the boundary of the infarction and induces wave patterns which appear as several focal wave sources on the epicard and endocard. We have traced the filament of the vortex and show its dynamics. Continuous stimulation of the heart at high frequency resulted in the Wenckebach effect.

[1]  R Lazzara,et al.  Re‐entrant Ventricular Arrhythmias in the Late Myocardial Infarction Period: 2. Patterns of Initiation and Termination of Re‐entry , 1977, Circulation.

[2]  D. Durrer,et al.  Total Excitation of the Isolated Human Heart , 1970, Circulation.

[3]  P. Wolf,et al.  Stimulus-induced critical point. Mechanism for electrical initiation of reentry in normal canine myocardium. , 1989, The Journal of clinical investigation.

[4]  John J. Tyson,et al.  The Dynamics of Scroll Waves in Excitable Media , 1992, SIAM Rev..

[5]  M Restivo,et al.  Ventricular arrhythmias in the subacute myocardial infarction period. High-resolution activation and refractory patterns of reentrant rhythms. , 1990, Circulation research.

[6]  A. Panfilov,et al.  Vortex initiation in a heterogeneous excitable medium , 1991 .

[7]  P D Wolf,et al.  Comparison of activation during ventricular fibrillation and following unsuccessful defibrillation shocks in open-chest dogs. , 1990, Circulation research.

[8]  Y Rudy,et al.  Cellular responses to electrical stimulation: a study using a model of the ventricular cardiac action potential. , 1993, Advances in experimental medicine and biology.

[9]  D. Noble.  A modification of the Hodgkin—Huxley equations applicable to Purkinje fibre action and pacemaker potentials , 1962, The Journal of physiology.

[10]  P B Corr,et al.  Electrophysiologic mechanisms underlying arrhythmias due to reperfusion of ischemic myocardium. , 1987, Circulation.

[11]  Alexander V. Panfilov,et al.  Modelling re-entry in a finite element model of the heart , 1993 .

[12]  S. Pogwizd,et al.  Mechanisms underlying the development of ventricular fibrillation during early myocardial ischemia. , 1990, Circulation research.

[13]  G. W. Beeler,et al.  Reconstruction of the action potential of ventricular myocardial fibres , 1977, The Journal of physiology.

[14]  A. Winfree,et al.  Scroll-Shaped Waves of Chemical Activity in Three Dimensions , 1973, Science.

[15]  R. FitzHugh.  Impulses and Physiological States in Theoretical Models of Nerve Membrane. , 1961, Biophysical journal.

[16]  A. Panfilov.  Three Dimensional Vortices in Active Media , 1991 .

[17]  P. Wolf,et al.  Mechanism of Ventricular Vulnerability to Single Premature Stimuli in Open‐Chest Dogs , 1988, Circulation research.

[18]  C F Starmer,et al.  Vulnerability in an excitable medium: analytical and numerical studies of initiating unidirectional propagation. , 1993, Biophysical journal.

[19]  D. Noble,et al.  Reconstruction of the electrical activity of cardiac Purkinje fibres. , 1975, The Journal of physiology.

[20]  James P. Keener,et al.  Re-entry in an anatomical model of the heart , 1995 .

[21]  N. El-Sherif,et al.  Reentrant ventricular arrhythmias in the late myocardial infarction period in the dog. 13. Correlation of activation and refractory maps. , 1985, Circulation research.

[22]  P B Corr,et al.  Reentrant and Nonreentrant Mechanisms Contribute to Arrhythmogenesis During Early Myocardial Ischemia: Results Using Three‐Dimensional Mapping , 1987, Circulation research.

[23]  M. Janse,et al.  Electrophysiological mechanisms of ventricular arrhythmias resulting from myocardial ischemia and infarction. , 1989, Physiological reviews.

[24]  S. Yoshizawa,et al.  An Active Pulse Transmission Line Simulating Nerve Axon , 1962, Proceedings of the IRE.

[25]  V. Krinsky.  Mathematical models of cardiac arrhythmias (spiral waves). , 1978, Pharmacology & therapeutics. Part B: General & systematic pharmacology.

[26]  W. Baxter,et al.  Spiral waves of excitation underlie reentrant activity in isolated cardiac muscle. , 1993, Circulation research.