Normal:

(I, II, aVF) + → vector between +90 and -30

Trick: draw the vector using amplitude of I and aVF QRS complex

Abnormal:

RAD - Right Axis Deviation

• RV Hypertrophy ECG

LAD - Left Axis Deviation

• LV Hypertrophy ECG
• Right superior axis (“Indeterminate”): both -