75-Year-Old Woman With Chest Pain and Shortness of Breath

A 75-year-old woman with a newly discovered ovarian mass concerning for malignancy and recently diagnosed (1 month previously) bilateral pulmonary emboli (PE) presented to the emergency department with sudden-onset, heavy chest pain while having lunch with her friends. The pain radiated to her back, did not worsen with postural changes, and was associated with shortness of breath. Because of her recent diagnosis of PE, she sought further evaluation. She had been compliant with her medication regimen (twice daily apixaban, the only medication she was taking) for the past month. Her medical history was remarkable for hyperlipidemia and obstructive sleep apnea. She reported no history of coronary artery disease (CAD), diabetes, hypertension, or tobacco use. On presentation, vital signs revealed a body mass index of 36 kg/m2, heart rate of 80 beats/ min, blood pressure of 205/89 mm Hg, temperature of 36.8°C, respiratory rate of 16 breaths/min, and normal oxygen saturation while breathing room air. Physical examination findings were notable for normal heart sounds, clear lung auscultation, and symmetric peripheral pulses. Initial electrocardiography (ECG) revealed normal sinus rhythm with no ST-segment changes. Laboratory evaluation revealed the following (reference ranges provided parenthetically): white blood cell count, 7.8 x 109/L (3.4 to 9.6 x 109/L); hemoglobin, 13.5 g/dL (11.6 to 15.0 g/dL); platelet count, 136 x 109/L (157 to 371 x 109/L); sodium, 143 mmol/L (135 to 145 mmol/L); potassium, 4.1 mmol/L (3.6 to 5.2 mmol/L); and creatinine, 0.88 mg/dL (0.59 to 1.04 mg/dL). Additionally, her N-terminal pro-B-type natriuretic peptide level was 84 pg/mL (10 to 227 pg/mL), and her initial high-sensitivity troponin concentration was 340 ng/L (