Which statement best differentiates NSTEMI from unstable angina?

• A. NSTEMI is defined by a troponin elevation indicating myocardial necrosis
• B. Unstable angina may have no troponin elevation
• C. NSTEMI may show troponin elevation with dynamic ECG changes, whereas unstable angina may have dynamic ECG changes without troponin elevation
• D. Unstable angina requires immediate thrombolysis

Answer: (C)

Distinguishing NSTEMI from unstable angina centers on myocardial necrosis as shown by troponin. In NSTEMI, troponin rises, reflecting cardiomyocyte death, and patients may have dynamic ischemic changes on the ECG. In unstable angina, troponin remains normal because there is ischemia without necrosis, though the ECG can still show dynamic changes. So the best statement captures both the troponin status and the ECG activity: troponin elevation with possible ECG changes indicates NSTEMI, while absence of troponin elevation with ischemic ECG changes points to unstable angina. Note that thrombolysis is not used for NSTEMI or unstable angina; it’s reserved for STEMI.