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| Title: | SPATIOTEMPORAL DYNAMICS OF VENTRICULAR FIBRILLATION IN AN ANISOTROPIC HUMAN HEART MODEL
Supported by research grants from the Canadian Institutes of Health Research, the Heart & Stroke Foundation of Nova Scotia, and the Natural Sciences and Engineering Council of Canada. |
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| DOI No: | 10.1142/9789812702234_0046 | |
| Source: | ADVANCES IN ELECTROCARDIOLOGY 2004 (pp 154-157) | |
| Author(s): | J. R. FITZ-CLARKE
Dept. of Physiology & Biophysics, Dalhousie University, Halifax Nova Scotia B3H 4H7, Canada J. C. CLEMENTS Dept. of Mathematics & Statistics, Dalhousie University, Halifax Nova Scotia B3H 4H7, Canada B. M. HORÁČEK Dept. of Physiology & Biophysics, Dalhousie University, Halifax Nova Scotia B3H 4H7, Canada |
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| Abstract: | We used computer simulations to study ventricular fibrillation (VF) in a three-dimensional (3-D) anisotropic human heart model comprised of 2.46 million elements. A new model of cardiac action potential, based on the Luo-Rudy formulation, was developed to simulate dynamics of ionic currents (INa, Ica, IK, IK1, Ito) in human ventricular myocytes; it contains the minimal number of currents necessary to capture the essential behaviour of endocardial, epicardial, and M cells, and it allows simulation of various pharmacological interventions. Re-entrant circuits were induced, and evolved into 3-D scroll waves. Wave stability was altered by manipulating restitution curves of action potential duration to achieve either solitary fixed or meandering spiral waves, which remained stable or fractionated into VF, depending on ionic conductances and gating time constants. We propose a scheme for characterizing subtypes of VF depending on dominant frequency, number of reentrant circuits, and Lyapunov exponents. Spatiotemporal dynamics of simulated arrhythmias corresponded well with optical maps reported in the literature, and demonstrated the feasibility of simulating realistically malignant ventricular arrhymias in a human heart model. | |
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