A patient in their 40s with no history of cardiovascular disease presented to the emergency department with a constant, substernal chest pain accompanied by sweating, which had started one and a half hours prior.
On arrival, the patient’s vital signs were as follows: blood pressure, 158/77 mm Hg; pulse, 78 beats/min; temperature, 36.0 °C; respiratory rate, 16 breaths/min; and oxygen saturation was 95% on room air. The patient was hemodynamically stable, and physical examination findings were unremarkable. Results of blood chemistry tests and complete blood cell count were within normal limits. The result of an initial troponin I test was normal. An electrocardiogram (ECG) was obtained (Figure, A). Forty minutes later, a preoperative ECG was performed (Figure, B).