If the AV node is damaged so that it can no longer transmit the signal from the SA node (total heart block), will the ventricles continue to contract? Why or why not?
A) No: there are no cells left to pace and coordinate the heart beat.
B) Yes: the AV bundle will keep the heart going at the usual rate.
C) Yes: however, ventricular contractions will no longer follow atrial contractions, and the rate of ventricular contractions will be significantly slowed.
D) No: the SA node must be intact to pace the system.

Question

Quizplus · Accepted Answer

In the event of total heart block, where the AV node is damaged and cannot transmit signals from the SA node, the ventricles can still contract due to the presence of secondary pacemaker cells located in the ventricles themselves. These cells can initiate contractions independently, albeit at a slower rate than the normal rhythm set by the SA node, leading to a significant reduction in the heart rate. This means that while the ventricles continue to beat, their contractions are no longer synchronized with the atrial contractions, resulting in a less efficient pumping action.

If the AV Node Is Damaged So That It Can