What is mainly responsible for the delay between the atrial and ventricular contractions?
A.
the shallow slope of AV node pacemaker potentials
B.
slow action potential conduction velocity of AV node cells
C.
slow action potential conduction velocity along atrial muscle cell membranes
D.
slow action potential conduction in the Purkinje network of the ventricles
E.
greater parasympathetic nerve firing to the ventricles than to the atria