Q. An 83-year-old male presents to the emergency department with a 3-hour history of acute substernal chest pain. He denies any trauma or episodes of similar symptoms, including angina pectoris. The pain began suddenly after dinner this evening, and is described as a sharp “tearing” sensation that radiates through to his scapula with 9/10 intensity. He reports his symptoms worsen with activity, and that rest is an alleviating factor. On physical examination, the patient is diaphoretic, and his blood pressure is 180/100 mm Hg, pulse is 92/min, respiratory rate is 18/min, and oxygen saturations are 95% on room air. Chest auscultation reveals normal lung sounds bilaterally, and his cardiac examination is also normal. While waiting for his wife to retrieve a current medication list, you order an electrocardiogram (EKG) and chest x-ray (see below). Based on the information you have at this point in time, what is the best medication to administer to this patient?