EXCITATION AND EXTRACELLULAR ELECTROGRAMS IN NORMAL AND FIBROTIC TWO-DIMENSIONAL CARDIAC TISSUE: A MODEL STUDY.

A modeling system, consisting of up to 125,000 model cells electronically coupled using the anisotropic bidomain concept, has been developed. The system is used to study propagation, and the resultant extracellular field in both normal and fibrotic cardiac tissue. Simulations of excitation and electrograms matched well with both experimental work and previous model studies, and clearly demonstrate the role of anisotropy on both the propagation of excitation, and electrograms. They also suggest there is a large degree of side-to-side uncoupling of cardiac fibers after infarction, and that this is an important factor in the appearance of fractionated electrograms.