Which of the Following is Least Related to Tachydysrhythmias

Question

Which of the following is least related to tachydysrhythmias?
A) Sympathetic nervous system activation
B) Beta1-adrenergic receptor activation
C) (+) Dromotropic effect
D) Vagal discharge

Accepted Answer

Vagal discharge is least related to tachydysrhythmias, as activation of the parasympathetic nervous system (mediated by the vagus nerve) slows down heart rate and can actually counteract tachycardic effects. The other choices all involve activation of the sympathetic nervous system or pathways that lead to increased heart rate and can contribute to tachydysrhythmias.