A 65-year-old male with a history of hypertension and diabetes presents with discomfort in his left arm and jaw, accompanied by nausea and diaphoresis. His ECG shows ST depression in leads V3-V5 and T-wave inversions in leads II, III, and aVF. Cardiac enzymes are pending. What is the MOST likely diagnosis?
- AAcute aortic dissection
- BNSTEMI/Unstable Angina
- CStable angina
- DPericarditis
Show answer & explanationAnswer & explanation
Correct answer: B. NSTEMI/Unstable Angina
The patient's symptoms (discomfort radiating to arm/jaw, nausea, diaphoresis) are classic for acute coronary syndrome. The ECG findings of ST depression and T-wave inversions, without ST elevation, are indicative of non-ST elevation myocardial infarction (NSTEMI) or unstable angina. The distinction between NSTEMI and unstable angina relies on cardiac enzyme elevation, which is pending.
Why the other options are wrong
- A. Acute aortic dissection presents with tearing pain and often differential blood pressures, not typically ST depression/T-wave inversion.
- C. Stable angina symptoms are typically relieved by rest or nitroglycerin and have a predictable pattern; this patient's symptoms are acute onset and severe.
- D. Pericarditis usually presents with pleuritic chest pain, often relieved by leaning forward, and diffuse ST elevation (not depression) with PR depression.
NSTEMI/Unstable Angina Diagnosis
Non-ST elevation myocardial infarction (NSTEMI) and unstable angina are forms of acute coronary syndrome characterized by ischemic symptoms and ECG changes (ST depression or T-wave inversion) without ST elevation. NSTEMI involves elevated cardiac biomarkers, while unstable angina does not.
- Symptoms: chest discomfort (angina equivalent), dyspnea, nausea, diaphoresis.
- ECG: ST depression (horizontal or downsloping) and/or T-wave inversion.
- No persistent ST elevation.
- Cardiac enzymes distinguish NSTEMI from unstable angina (elevated in NSTEMI).
Memory trick: ACS: STEMI, NSTEMI, Unstable Angina - ECG and Enzymes Tell All!