Bipolar stimulation of a three-dimensional bidomain incorporating rotational anisotropy

• Published in: IEEE transactions on biomedical engineering Vol. 45; no. 4; pp. 449 - 462
• Main Authors: Muzikant, A.L., Henriquez, C.S.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.04.1998; Institute of Electrical and Electronics Engineers
• Subjects: Anisotropic magnetoresistance; Anisotropy; Biological and medical sciences; Biothermics. Biomagnetism. Bioelectricity; Cardiac tissue; Cardiovascular system; Electric Conductivity; Electrodes; Electromagnetic Fields; Electrophysiology; Endocardium - physiology; Extracellular; Fundamental and applied biological sciences. Psychology; Laplace equations; Mathematical models; Membrane Potentials; Models, Cardiovascular; Muscles; Myocardium; Optical fiber polarization; Pericardium - physiology; Physiological models; Sampling methods; Steady-state; Surface Properties; Tissue; Tissues, organs and organisms biophysics; Bipolar electrode; Electrical properties; Potential distribution; Electrical stimulus; Modeling; Tissue; Simulation; Anisotropy; Myocardium; Three dimensional system; Rotation behavior; Fiber orientation; Circulatory system
• ISSN: 0018-9294; 1558-2531
• DOI: 10.1109/10.664201

A bidomain model of cardiac tissue was used to examine the effect of transmural fiber rotation during bipolar stimulation in three-dimensional (3-D) myocardium. A 3-D tissue block with unequal anisotropy and two types of fiber rotation (none and moderate) was stimulated along and across fibers via bipolar electrodes on the epicardial surface, and the resulting steady-state interstitial (/spl Phi//sub /spl epsiv//) and transmembrane (V/sub m/) potentials were computed. Results demonstrate that the presence of rotated fibers does not change the amount of tissue polarized by the point surface stimuli, but does cause changes in the orientation of /spl Phi//sub /spl epsiv//, and V/sub m/ in the depth of the tissue, away from the epicardium. Further analysis revealed a relationship between the Laplacian of /spl Phi//sub /spl epsiv//, regions of virtual electrodes, and fiber orientation that was dependent upon adequacy of spatial sampling and the interstitial anisotropy. These findings help to understand the role of fiber architecture during extracellular stimulation of cardiac muscle.