A 70-year-old male with a history of CHD presents with severe chest pain. His ECG shows ST-segment depression in leads V1-V4. His troponin levels are elevated. What could be the diagnosis and the next steps?
The patient's symptoms, ECG changes, and elevated troponin levels suggest a non-ST segment elevation myocardial infarction (NSTEMI), which is part of the spectrum of acute coronary syndrome (ACS). He should be admitted to the hospital for close monitoring and started on medical therapy including aspirin, other antiplatelet agents, nitroglycerin, and potentially heparin or other anticoagulants. A coronary angiogram should be considered to assess the need for revascularization.