ECG AXIS

ECG AXIS

• • Normal: QRS up in lead 1, 2, and aVF (-30° - +90°)

  • Normal: QRS up in lead 1, and lead 2; down in aVF (-30° - +60°)

  • LAD:

    • Beyond -30°

    • QRS up in lead 1, down in aVF, and lead 2 (S > R in lead II)

    • Etiologies: LVH, LBBB, inferior MI, elevated diaphragm, WPW

  • RAD :

    • Beyond +90

    • QRS down in lead 1, and up in aVF (S > R in lead I)

    • Etiologies: RVH, RBBB, PE, COPD, lateral MI, WPW, septal defects.

  • Extreme or far RAD: QRS down in both leads 1 and aVF.