Continuous and discontinuous propagation in heart muscle

Although cardiac muscle has been considered as an electrical syncytium for a long time, several aspects of conduction of the electrical impulse in the heart could not be explained by a continuous approach. Even the simple anisotropic nature of cardiac muscle gives rise to a number of conduction characteristics that contradicts with results from continuous models. It is, however, evident that cardiac conduction must be discontinuous in nature owing to recurrent resistive discontinuities caused by the cellular interconnections. In this review, the role of discontinuities at the cellular and macroscopic level on cardiac propagation will be discussed.