A 46-year-old man with no significant medical history presented to the emergency department (ED) 6 hours after a 20-minute episode of chest pain and diaphoresis that occurred at rest and resolved spontaneously. Two days earlier, he reported a similar 20-minute episode of chest pain and diaphoresis. The patient currently smoked 30 cigarettes per day and had a 20 pack-year history of smoking. He was taking no daily medications and had no family history of cardiovascular disease. On admission to the ED, the patient was asymptomatic. Blood pressure was 102/74 mm Hg, heart rate was 84/min, and oxygen saturation was 100% on room air. His physical examination results were unremarkable. Laboratory testing produced the following results: troponin T, 16 ng/mL (reference, <14 ng/mL); creatine kinase (CK), 82 U/L (1.37 µkat/L) (reference, <190 U/L [<3.17 µkat/L]); CK-MB, 16 U/L (reference, <24 U/L); low-density lipoprotein (LDL) cholesterol, 106 mg/dL (2.75 mmol/L) (reference, <130 mg/dL [<3.37 mmol/L]); and high-density lipoprotein (HDL) cholesterol, 38 mg/dL (0.98 mmol/L) (reference, >35 mg/dL [>0.91 mmol/L]). His initial electrocardiogram (ECG) is shown in Figure 1.