MedXpertQA MM Extended

Q: A 37-year-old male presents to the emergency department with a sudden onset of palpitations. An initial electrocardiogram reveals paroxysmal supraventricular tachycardia at a rate of 160 beats per minute. Despite receiving multiple doses of adenosine, the arrhythmia persists. After consulting with the on-call electrophysiologist, the treating physician decides to administer a medication that modifies the cardiac action potential as shown in the accompanying figure. Which of the following medications was most likely used to manage this patient’s condition? Answer Choices: (A) Procainamide (B) Lidocaine (C) Propafenone (D) Diltiazem (E) Ibutilide A: Let's think step by step. Conclude your response with the line: "Therefore, among A through E, the answer is X" where X is the correct answer letter (A, B, C, D, or E).