The conduction velocity is maximum in

The velocity of conduction of the excitatory action potential signal along both atrial and ventricular muscle fibers is about 0.3 to 0.5 m/sec, or about 1/250 the velocity in very large nerve fibers and about 1/10 the velocity in skeletal muscle fibers. The velocity of conduction in the specialized hea conductive system--in the Purkinje fibers is as great as 4 m/sec in most pas of the system, which allows reasonably rapid conduction of the excitatory signal to the different pas of the hea. Ref: Guyton and Hall textbook of medical physiology 13th edition. Page: 111