During carotid sinus reflex testing, what is the expected change in pulse when the carotid artery is occluded?

• A. Pulse should decrease
• B. Pulse should increase
• C. Pulse remains unchanged
• D. Pulse becomes irregular

Answer: (A)

The carotid sinus houses baroreceptors that regulate blood pressure by adjusting heart rate through autonomic reflexes. When the carotid sinus is stimulated (as in occluding or massaging that area), the baroreceptors increase their firing. This signals the brain to elevate parasympathetic (vagal) activity to the heart and reduce sympathetic drive. The net result is a slowing of the heart rate, i.e., a decrease in pulse.

So, a lower pulse is the expected response. If the pulse stays the same or becomes irregular, that would suggest an abnormal or blunted reflex rather than the normal parasympathetic-mediated bradycardia.