🫀 STEMI vs NSTEMI ECG Differential Simulator

Reading the ST Segment First

ST-segment shape splits acute coronary syndromes into two urgent tracks.

• ST elevation: STEMI ECG sign (≥1mm, contiguous leads)
• ST depression: NSTEMI ECG sign (or normal / T inversion)
• Troponin +: Shared marker (both are troponin-positive)
• 12-lead ECG: First test (within 10 minutes of arrival)

Why the ECG decides the pathway

Placeholder: ST elevation implies complete occlusion needing emergency reperfusion.

Placeholder: ECG pattern, not symptoms alone, drives the treatment clock.

Full-Thickness Occlusion

Complete coronary occlusion damages the entire wall thickness.

• Complete: Occlusion type (total vessel occlusion)
• 3 of 3: Wall layers hit (epi + myo + endocardium)
• ST↑ + Q wave: ECG hallmark (evolving pattern)
• High: Risk if delayed (myocardium at risk grows)

Transmural damage mechanism

Placeholder: full-thickness ischemia elevates the ST segment on ECG.

Placeholder: time lost equals muscle lost in transmural infarction.

Partial-Thickness Ischemia

Subendocardium is most vulnerable, so injury stays partial-thickness.

• Partial/subtotal: Occlusion type (or transient occlusion)
• Inner 1 of 3: Wall layers hit (subendocardial band)
• ST↓ / T inversion: ECG hallmark (or normal ECG)
• Troponin: Diagnosis needs (ECG alone insufficient)

Subendocardial vulnerability

Placeholder: inner wall gets least collateral flow, so it ischemes first.

Placeholder: normal ECG never excludes NSTEMI without troponin.

STEMI: Door-to-Balloon Race

STEMI triggers immediate cath lab activation, bypassing risk scoring.

• ≤90 min: Goal (door-to-balloon time)
• Activate cath lab: Action (pre-hospital if possible)
• Primary PCI: Strategy (or fibrinolysis if delayed)
• ECG alone: Decision basis (no waiting for troponin)

Emergent reperfusion logic

Placeholder: every 30-minute delay increases mortality risk.

Placeholder: cath lab activation happens on ECG, not lab results.

NSTEMI: Timed, Risk-Based Angiography

NSTEMI care uses risk scores to time invasive strategy, not rush it.

• GRACE/TIMI score: Tool (risk stratification)
• <24 h: High-risk timing (early invasive strategy)
• 24–72 h: Lower-risk timing (or ischemia-guided)
• Antiplatelet/anticoag: Medical therapy (started immediately)

Why NSTEMI is not rushed the same way

Placeholder: risk score guides whether angiography is urgent or elective.

Placeholder: stability allows risk-based timing instead of emergent PCI.