A 64 year-old male comes to the emergency room and reports that he developed chest pain, shortness of breath and palpitations for the last 6 hours. On further questioning, he reveals that over the last two days he has been drinking excessive amounts of alcohol in celebration of a friend’s birthday. His past medical history is significant only for GERD for which he takes omeprazole. ECG showed irregularly, irregular QRS complexes with no P waves. Laboratory tests revealed normal levels of troponin; elevated liver enzymes and normal renal function. After medical treatment, his condition has improved. He no longer has chest pain or shortness of breath. However, he is still experiencing episodes of palpitations. He is breathing comfortably on room air with oxygen saturation by pulse oximetry 97%. Blood pressure is 120/80 mm Hg. Heart rate is 102 beats/min at rest. At the time of discharge, which of the following medications is indicated for this patient?
