Review Question - QID 107904

A 63-year-old male is admitted to the hospital after an episode of syncope. He endorses vague abdominal discomfort as well as increased bilateral lower leg swelling for the past month. He has had intermittent left shoulder discomfort on exertion, which he states has been increasing in frequency. The patient’s vitals signs are as follows: Temperature is 98.7 deg F (37.1 deg C), blood pressure is 153/78 mmHg, pulse is 54/min, respirations are 14/min, and oxygen saturation is 98% on room air. The patient’s cardiac exam is notable for bradycardia without any murmurs. Chest radiograph appears as follows (Figure A). Which of the following changes on electrocardiogram would be most consistent with this patient’s presentation?