Lesson Objectives:

• Develop a structured approach to ECG interpretation.

• Recognize key arrhythmias and ischemic changes.

• Differentiate between STEMI, NSTEMI, and normal ECG variants.

Stepwise ECG Interpretation (RRAI-PLAT)

1️⃣ Rate: Normal (60-100 bpm), tachycardia (>100 bpm), bradycardia (<60 bpm).
2️⃣ Rhythm: Sinus vs. atrial fibrillation/flutter, premature beats.
3️⃣ Axis: Normal (-30° to +90°), left axis deviation (LAD), right axis deviation (RAD).
4️⃣ Intervals:

• PR interval (normal: 120-200 ms) – prolonged in AV block.

• QRS complex (<120 ms) – widened in bundle branch blocks (LBBB/RBBB).

• QT interval – prolonged in long QT syndrome (risk of torsades de pointes).
  5️⃣ P-wave abnormalities: Peaked in right atrial enlargement, notched in left atrial enlargement.
  6️⃣ LBBB vs. RBBB:

• LBBB: “W” in V1, “M” in V6.

• RBBB: “M” in V1, “W” in V6.
  7️⃣ Ischemic Changes:

• ST Elevation: STEMI (localized to coronary artery territory).

• ST Depression/T-wave inversion: NSTEMI or unstable angina.

🔹 Classic ECG Patterns:

• Inferior STEMI: ST elevation in II, III, aVF → RCA involvement.

• Anterior STEMI: ST elevation in V1-V4 → LAD involvement.

• Atrial Fibrillation: No P-waves, irregularly irregular rhythm.

• Ventricular Tachycardia: Wide QRS, rapid rate, life-threatening.