A 62-year-old male with underlying COPD develops a viral upper respiratory infection and begins taking an over-the-counter decongestant. Shortly thereafter he experiences palpitations and presents to the emergency room, where the following rhythm strip is obtained, demonstrating
Normal sinus rhythm Junctional rhythm Atrial flutter with 4:1 atrioventricular block Paroxysmal atrial tachycardia with 2:1 atrioventricular block