Makindo Medical Notes

Related Subjects: |ECG Basics |ECG Axis |ECG Analysis |ECG LAD |ECG RAD |ECG Low voltage |ECG Pathological Q waves |ECG ST/T wave changes |ECG LBBB |ECG RBBB |ECG short PR |ECG Heart Block |ECG Asystole and P wave asystole |ECG QRS complex |ECG ST segment |ECG: QT interval |ECG: LVH |ECG RVH |ECG: Bundle branch blocks |ECG Dominant R wave in V1 |ECG Acute Coronary Syndrome |ECG Crib sheets

🫀 ECG, MI & Coronary Arteries

📋 Criteria for Diagnosing STEMI

• ST elevation in ≥2 contiguous leads >1 mm (except V2–V3 thresholds below).
• V2–V3: ≥2 mm in men >40 yrs, ≥2.5 mm in men <40 yrs, ≥1.5 mm in women.
• New or presumed new LBBB.
• Isolated posterior MI (diagnose by reciprocal ST depression in V1–V3).
• Reciprocal changes support diagnosis.

⚠️ Differentials of ST Elevation

• STEMI
• Early repolarisation ⭐ (benign, young athletes, no reciprocal change)
• Myopericarditis ❤️‍🔥 (saddle-shaped STE in all except aVR)
• Prinzmetal’s angina 🌙 (vasospasm, transient)
• LV aneurysm (post-MI, persistent STE)
• Brugada syndrome ⚡ (V1–V3 STE, risk of sudden death)
• Takotsubo cardiomyopathy 🐙
• During PCI or angioplasty

🔎 Early Repolarisation (Mimics Anterior STEMI)

• Incidence: 5–13% (common in young athletes).
• J-point elevation ≥1 mm in ≥2 contiguous leads (often inferior or lateral).
• Concave morphology, no reciprocal changes, large T waves.
• Benign – but must exclude ACS if uncertain.

🩺 STEMI Evolution

• 1️⃣ Hyperacute T waves
• 2️⃣ ST elevation ± reciprocal depression
• 3️⃣ T wave inversion
• 4️⃣ Loss of R wave height
• 5️⃣ Q waves (transmural infarct, “electrical window”)

NSTEMI / Ischaemia

• Widespread ST depression
• T wave flattening/inversion
• Deep anterior T inversions → LAD stenosis
• Deep inferior T inversions → RCA stenosis

📐 Modified Sgarbossa Criteria (LBBB)

• ≥1 mm concordant STE in ≥1 lead
• ≥1 mm concordant ST depression V1–V3
• ≥1 mm STE with discordance ≥25% of preceding S-wave depth

🧭 Correlating ECG with Culprit Vessel