Purkinje cells are specialized for rapid propagation in the heart. Furthermore, Purkinje fibers
as the source as well as the perpetuator of arrhythmias is a familiar finding. This is not
surprising considering their location in the heart and their unique cell ultrastructure, cell
electrophysiology, and mode of excitation–contraction coupling. This review touches on
each of these points as we outline what is known today about Purkinje fibers/cells.