A 59-year-old is admitted to the intensive care unit for chest pain. ECG revealed Q waves and an ST depression in the anterior leads. His cardiac enzymes were elevated and he was treated with nitroglycerin and inotropic support for a low blood pressure. He was discharged 7 days later and was again seen in the emergency department 3 weeks later. His complaints were of a low-grade fever, chest pain, nausea, and generalized malaise. He complained of pain radiating to his neck. ECG revealed generalized ST segment elevation. What is the most likely diagnosis?