Slowest conduction of velocity occurs in
The total delay in the A-V nodal and A-V bundle system is about 0.13 second. This delay, in addition to the initial conduction delay of 0.03 second from the sinus node to the A-V node, makes a total delay of 0.16 second before the excitatory signal finally reaches the contracting muscle of the ventricles.Ref: Guyton and Hall textbook of medical physiology 13th edition. Page:125
Atrial muscle
A. V. node
Purkinje fibre
Ventricular muscles
Cardiovascular system