Membrane polarization induced in the myocardium by defibrillation fields: an idealized 3-D finite element bidomain/monodomain torso model

• Published in: IEEE transactions on biomedical engineering 1999-01, Vol.46 (1), p.26-34
• Main Authors: Qiuju Huang, Eason, J.C., Claydon, F.J.
• Format: Article
• Language: English
• Subjects: Analytical models; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Biological and medical sciences; Biological membranes; Biomembranes; Cardiovascular system; Computational modeling; Computer Simulation; Defibrillation; Electric Countershock; Electrodes; Electrophysiology; Emergency and intensive cardiocirculatory care. Cardiogenic shock. Coronary intensive care; Finite Element Analysis; Finite element method; Finite element methods; Fundamental and applied biological sciences. Psychology; Heart; Heart - physiology; Humans; Intensive care medicine; Mathematical models; Mathematics; Medical sciences; Membrane Potentials - physiology; Microelectrodes; Models, Cardiovascular; Myocardium; Neural Conduction - physiology; Optical fiber polarization; Physiological models; Polarization; Torso; Vertebrates: cardiovascular system
• ISSN: 0018-9294; 1558-2531
• DOI: 10.1109/10.736750

This study develops a three-dimensional finite element torso model with bidomain myocardium to simulate the transmembrane potential (TMP) of the heart induced by defibrillation fields. The inhomogeneities of the torso are modeled as eccentric spherical volumes with both the curvature and the rotation features of cardiac fibers incorporated in the myocardial region. The numerical computation of the finite element bidomain myocardial model is validated by a semianalytic solution. The simulations show that rotation of fiber orientation through the depth of the myocardial wall changes the pattern of polarization and decreases the amount of cardiac tissue polarized compared to the idealized analytic model with no fiber rotation incorporated. The TMP induced by transthoracic and transvenous defibrillation fields are calculated and visualized. The TMP is quantified by a continuous measure of the percentage of myocardial mass above a potential gradient threshold. Using this measure, the root mean square differences in TMP distribution produced by reversing the electrode polarity for anterior-posterior and transvenous electrode configurations are 13.6 and 28.6%, respectively. These results support the claim that a bidomain model of the heart predicts a change of defibrillation threshold with reversed electrode polarity.