Recurrent Chest Pain in a 42-Year-Old Woman With a History of NSTE-ACS
A 42-year-old woman was admitted to an inpatient cardiology service with complaint of sudden onset of severe substernal chest pain associated with nausea and diaphoresis. She had a history, nine months prior to admission, of non–ST-elevation acute coronary syndromes (NSTE-ACS) treated at an outside hospital, with angiographic evidence of 75% stenosis of the distal left anterior descending artery. No percutaneous intervention had been performed at that time, and the patient had been started on medical therapy. She also reported a history of atrioventricular nodal reentry tachycardia, treated with radiofrequency ablation six months prior to admission at another hospital. She denied any family history of coronary artery disease or sudden death. In addition, she was very physically active and denied chest pain on exertion.
In the emergency room, the patient's electrocardiogram (ECG) showed sinus rhythm with sinus arrhythmia. Her blood pressure was 105/70, heart rate 65 bpm, respiratory rate 16, and O2 saturation 100% on room air. The chest x-ray was unremarkable. Laboratory analyses were within normal limits, including two troponin levels drawn six hours apart. Her physical exam showed a pleasant, fit woman in no acute distress; no jugular venous distension and no neck bruits were noted. Lungs were clear to auscultation. Heart rhythm was regular, with normal S1, physiologically split S2, and no murmurs, rubs, or gallops. The abdomen was soft, non-distended, and non- tender, with normoactive bowel sounds. Groin auscultation was remarkable for bilateral bruits, more prominent on the left side. Peripheral pulses were normal in all extremities. In the emergency room, for a presumptive diagnosis of unstable angina, she was given aspirin 325 mg, clopidogrel, metoprolol tartrate, atorvastatin, and subcutaneous enoxaparin, with resolution of the chest pain. After admission to the cardiology service, a transthoracic echocardiogram showed normal left ventricular size, function (ejection fraction 60%), and wall motion. Right ventricular size and function were also within normal limits. No significant valvular abnormalities were noted. Arterial duplex of the inferior limbs showed no abnormalities of the inflow, outflow, and runoff. She continued to remain asymptomatic.
Which of the following would be the most appropriate next diagnostic test(s) for this patient?