This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Pharmacology
A 45-year-old man has recently been the recipient of a hea transplant. Which one of the following drug is least likely to cause tachycardia in this patient 
Select and explain. 
A. Amphetamine, B. Dobutamine, C. Epinephrine, D. Norepinephrine
A: Amphetamine
Answer: A: Amphetamine 
Explanation: The transplanted hea doesn't have sympathetic innervation. Hence an indirectly acting sympathomimetic like Amphetamine has the least likelihood of causing tachycardia when compared to the directly acting ones.