Supported by NIH Grants HL4–1603 (ADM), HL4-3023 (Shu Chien, Institute for Biomedical Engineering, The University of California. San Diego, La Jolla. California. USA), and Training Grant HL07089 (SC), and NSF PY1 Grant BCS-91-57961 (ADM).
Nonuniform Muscle Fiber Orientation Causes Spiral Wave Drift in a Finite Element Model of Cardiac Action Potential Propagation
Version of Record online: 29 APR 2007
Journal of Cardiovascular Electrophysiology
Volume 5, Issue 6, pages 496–509, June 1994
How to Cite
ROGERS, J. M. and McCULLOCH, A. D. (1994), Nonuniform Muscle Fiber Orientation Causes Spiral Wave Drift in a Finite Element Model of Cardiac Action Potential Propagation. Journal of Cardiovascular Electrophysiology, 5: 496–509. doi: 10.1111/j.1540-8167.1994.tb01290.x
- Issue online: 29 APR 2007
- Version of Record online: 29 APR 2007
- Manuscript received 19 January 1994; Accepted for publication 6 April 1994
- FitzHugh-Nagumo equations;
- nonstationary propagation;
Mechanism for Spiral Wave Drift. Introduction: Reentrant tachyarrhythmias are thought to involve spiral waves of excitation and recovery that may be nonstationary. The effect of muscle fiber curvature on spiral and planar wave propagation was studied using a computational model.
Methods and Results: Two-dimensional anisotropic cardiac propagation was modeled using a finite element method to solve a modification of the FitzHugh-Nagumo equations. Spiral waves that propagated stably about a fixed core in tissue with a uniform fiber orientation were found to drift at an oblique angle to the fibers when the fibers curved. The drift velocity was linearly related to the fiber angle gradient and was 10% of the longitudinal propagation velocity with a gradient of 4 degree/cm. Planar wavefronts were also affected by fiber curvature. The maximal upstroke rate, propagation velocity, and the action potential amplitude all increased when the fibers curved toward the wavefront and decreased when they curved away. For example, when the fibers curved toward the wavefront with a moderate gradient of 15 degree/cm, maximal upstroke rate increased 74%, transverse propagation velocity increased 65%, and action potential amplitude increased 9%, This phenomenon caused the spiral wave drift: As a spiral wave traverses a cycle, the angle between the wavefront at the wavetip and the fibers changes periodically, thus altering the propagation parameters. These periodic changes affect the instantaneous radius of curvature of the wavetip path, which results in drift.
Conclusion: Spiral and planar waves are affected by muscle fiber curvature. The resulting dynamics may be important in determining the lifetime and stability of reentrant arrhythmias.