A 53-year-old man with multiple atherosclerotic risk factors, including HTN, hyperlipidemia, and tobacco use, presents with a 6-month history of DOE and exertional chest tightness. He has orthopnea and paroxysmal nocturnal dyspnea. Echocardiography reveals a severely dilated LV with an EF of 20% and global ventricular hypokinesis. The ECG is normal. The next step in diagnostic evaluation should be: a. Holter monitor b. Stress test with measurement of maximal oxygen consumption c. Coronary angiography d. Heart transplant evaluation
