A 70-year-old man comes to the physician for a 4-month history of shortness of breath, midsternal chest pain, and sweating. Each episode lasts 2-5 minutes and is precipitated by walking up the stairs in his home. His symptoms are relieved with rest. He has hypertension managed with lisinopril. He has smoked one pack of cigarettes daily for 50 years. Vitals are within normal limits. Lungs are clear to auscultation. Cardiac examination shows an S4 heart sound. There is no ankle edema. Which of the following is most likely to confirm the diagnosis?
Ambulatory ECG monitoring
Echocardiography
Exercise stress test
Measurement of ankle-brachial indices
Measurement of serum troponin
