FD is a 74-year-old man postoperative day 1 from a radical prostatectomy for prostate cancer. After breakfast, he develops palpitations and light-headedness. The surgical intern administers 6 mg IV...

FD is a 74-year-old man postoperative day 1 from a radical prostatectomy for prostate cancer. After breakfast, he develops palpitations and light-headedness. The surgical intern administers 6 mg IV adenosine, which promptly resolves the tachycardia.The tachycardia recurs 2 hours later and an ECG obtained during the second episode would most likely reveal:

A. AF

B. Multifocal atrial tachycardia

C. Atrial flutter

D. Sinus tachycardia

E. AV nodal re-entry tachycardia