Stable angina vs Acute coronary syndrome
How to tell Stable angina and Acute coronary syndrome apart when a board question makes them look alike.
Stable is predictable demand ischemia; new, worse, or rest pain is ACS until biomarkers and ECG classify it.
Side by side
Predictable exertional chest pressure relieved by rest or nitroglycerin.
New, worsening, or rest chest pain requiring ACS framing: unstable angina, NSTEMI, or STEMI.
Fixed atherosclerotic narrowing causes demand ischemia.
Plaque rupture or acute thrombus causes unstable ischemia, with troponin and ECG separating UA, NSTEMI, and STEMI.
Troponin is negative and symptoms follow a reproducible exertional pattern.
Troponin separates unstable angina from NSTEMI; ST elevation identifies STEMI.
The trap
A normal first troponin and a normal ECG do not move new-onset, rest, or crescendo pain into the stable category. Unstable angina is defined by the clinical pattern, not by the biomarker. Order serial troponins and ECGs every 3 to 6 hours and treat as ACS until two negative sets and risk-appropriate stress testing or coronary CT are clean. Sending a patient home on a single negative troponin is the highest-stakes error in this pair.
Watch it explained
The repair move
First decide stable pattern versus ACS pattern; then use ECG and troponin to classify ACS.
Try a free question
CoreA patient has substernal pressure only when walking uphill. It resolves within minutes of rest. ECG and troponin are normal. Which diagnosis best fits?
Show answer and explanation
Answer: A. Stable angina. Predictable exertional pain relieved by rest is stable angina.
Why the other choices are tempting
- B. Unstable angina is new, worsening, or rest pain with negative troponin.
- C. NSTEMI has myocardial injury with elevated troponin.
- D. STEMI has acute transmural injury with ST elevation.
- E. Pericarditis is positional/pleuritic and has diffuse ST elevation.
Flashcards
Tap a card to flip it.
What mechanism defines stable angina?
Fixed atherosclerotic narrowing creates reproducible demand ischemia during exertion.
What symptom pattern pushes angina into ACS framing?
New, worsening, crescendo, or rest pain should be treated as acute coronary syndrome until classified.
Quick answers
What is the fastest way to tell Stable angina from Acute coronary syndrome?
Stable is predictable demand ischemia; new, worse, or rest pain is ACS until biomarkers and ECG classify it.
What is the key clue for Stable angina?
Predictable exertional chest pressure relieved by rest or nitroglycerin.
What is the key clue for Acute coronary syndrome?
New, worsening, or rest chest pain requiring ACS framing: unstable angina, NSTEMI, or STEMI.
What is the common trap with Stable angina vs Acute coronary syndrome?
A normal first troponin and a normal ECG do not move new-onset, rest, or crescendo pain into the stable category. Unstable angina is defined by the clinical pattern, not by the biomarker. Order serial troponins and ECGs every 3 to 6 hours and treat as ACS until two negative sets and risk-appropriate stress testing or coronary CT are clean. Sending a patient home on a single negative troponin is the highest-stakes error in this pair.