A patient in their 70s presented to the emergency department with chest tightness and shortness of breath for 5 hours and loss of consciousness for 10 minutes. The patient’s medical history included metastatic rectal cancer and hypertension. On admission, the patient had a temperature of 36.0 °C, blood pressure of 52/26 mm Hg, pulse rate of 45 beats per minute, and respiratory rate of 6 breaths per minute. Examination revealed ecchymosis on the lower limbs, whereas cardiopulmonary examination was unremarkable. The N-terminal pro-brain natriuretic peptide level was 6770 ng/L (reference, 300-900 ng/L); however, the troponin I level was normal. A 12-lead electrocardiogram (ECG) obtained at admission is shown in Figure, A.