Under What Condition Will the AV Node Become the Pacemaker

Question

Under what condition will the AV node become the pacemaker?
A) When its rate of spontaneous depolarization exceeds that of the ventricular conduction cells
B) As a normal response to sympathetic nerve discharge
C) When its rate of spontaneous depolarization exceeds that of the SA node
D) In the presence of normal sinus rhythm

Accepted Answer

The AV node becomes the pacemaker if its rate of spontaneous depolarization exceeds that of the SA node. This can occur in certain conditions such as sinus node dysfunction or heart block, where the normal pacemaker function of the SA node is disrupted. In these cases, the AV node may take over as the primary pacemaker, but at a slower rate than the SA node, leading to a lower heart rate.