Chart — Cardiac
ACS Comparison Chart
Side-by-side comparison of stable angina, unstable angina, NSTEMI, and STEMI — organized by ECG findings, troponin status, degree of coronary occlusion, urgency, and treatment priorities.
Educational use only. ACS management requires provider assessment and institutional protocols. This chart supports learning and NCLEX preparation. This material supports nursing education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional policy, or medical direction. Always follow facility protocols and current provider orders.
ACS Spectrum Comparison
| Condition | ECG Findings | Troponins | Coronary Occlusion | Urgency |
|---|---|---|---|---|
| Stable Angina | Normal at rest; transient ST depression with exertion; resolves with rest or NTG | Normal — no myocardial necrosis | No occlusion — fixed stenosis limits blood flow during increased demand; no thrombus | Outpatient evaluation — schedule stress testing, optimize medical management; not an emergency |
| Unstable Angina (UA) | ST depression or T-wave changes possible; NO ST elevation; changes may be dynamic | Normal — troponin NOT elevated. This is the key distinguishing feature from NSTEMI | Partial — plaque rupture with non-occlusive thrombus; severely reduced flow without complete blockage | Urgent inpatient admission — high risk for progression to MI; risk stratify with TIMI or GRACE score |
| NSTEMI | ST depression and/or T-wave inversion; NO ST elevation; may have non-specific changes or normal ECG | ELEVATED — rising and falling pattern with clinical symptoms confirms diagnosis | Near-complete to partial — thrombus with residual flow; subendocardial necrosis (partial thickness) | Emergent admission — catheterization within 24–72 hrs (high-risk: <24 hrs; low-risk: <72 hrs) |
| STEMI | ST elevation ≥1 mm in ≥2 contiguous leads; reciprocal ST depression in opposite leads; eventual Q wave development | ELEVATED — but do not wait for results; diagnosis and activation made on ECG alone | Complete — occlusive thrombus; no residual flow; transmural (full-thickness) myocardial necrosis | IMMEDIATE EMERGENCY — activate cath lab now; door-to-balloon goal ≤90 min (PCI) or ≤30 min (thrombolytics) |
Treatment Summary
Stable AnginaLong-acting nitrates, beta-blockers, CCBs, aspirin; revascularization if refractory
Unstable Angina (UA)Aspirin, P2Y12 inhibitor, heparin, beta-blocker; early invasive vs conservative based on risk
NSTEMIAspirin + P2Y12 inhibitor (DAPT), heparin, beta-blocker, statin; early invasive per risk score
STEMIImmediate reperfusion (PCI preferred); aspirin + P2Y12 inhibitor + heparin; morphine if refractory pain; avoid NTG in inferior STEMI with RV involvement
Key Differentiating Facts
| Feature | Stable Angina | Unstable Angina | NSTEMI | STEMI |
|---|---|---|---|---|
| Troponin elevated? | No | No | Yes | Yes |
| ST elevation? | No | No | No | Yes |
| Complete occlusion? | No | No | No (partial) | Yes |
| Myocardial necrosis? | No | No | Yes (partial) | Yes (transmural) |
| Reperfusion needed? | No (medical mgmt) | No (risk-based) | Yes (cath ≤24–72 hrs) | Yes (immediate, ≤90 min) |
| Presentation | Exertional only | Rest, new onset, or crescendo | Rest pain with necrosis | Complete occlusion — rest pain |
NCLEX Pearls
- ›UA vs NSTEMI: Both have no ST elevation, but NSTEMI has elevated troponin — UA does not.
- ›STEMI diagnosis is made on ECG alone — do not wait for troponin results to activate protocol.
- ›STEMI = complete occlusion → transmural infarction; NSTEMI = partial occlusion → subendocardial infarction.
- ›New LBBB with ACS symptoms is treated as a STEMI equivalent — activate cath lab protocol.
- ›Inferior STEMI: check right-sided ECG for RV infarct before giving nitroglycerin.
- ›Door-to-balloon ≤90 min for PCI; ≤30 min for thrombolytics — time-critical for STEMI only.
- ›All ACS types receive aspirin immediately — STEMI additionally needs immediate reperfusion.
Related Resources
Acute Coronary Syndrome (ACS) GuideACS overview, pathophysiology, risk factors, clinical presentation, nursing priorities
Open →STEMI vs NSTEMI GuideECG differences, troponin findings, treatment priorities, nursing implications
Open →STEMI Activation Criteria ReferenceECG criteria, contiguous leads, new LBBB, posterior MI clues
Open →Troponin Interpretation ChartNormal, rising trend, peak, downtrending — clinical significance of each pattern
Open →EKG Rhythm Chart14 cardiac rhythms with rate, regularity, P wave, PR interval, and QRS features
Open →Standards & sources
Fact-checked Jun 20, 2026This page is written to align with AHA / ACC ACS Guidelines. It is an educational summary, not a citation of any single document — always verify specific doses, values, and protocols against current guidelines and your facility policy. How we source content →