Which of the Following Would Not Increase Heart Rate

Question

Which of the following would not increase heart rate?
A) increased sympathetic stimulation of SA node
B) decreased parasympathetic stimulation of nodal fibers
C) increased levels of epinephrine
D) faster depolarization of the pacemaker potential
E) beta blocking drugs

Accepted Answer

Beta blocking drugs are used to decrease heart rate by blocking the effects of epinephrine and norepinephrine on the heart. Therefore, it would not increase heart rate.