Right Axis Deviation

Causes of right axis deviation
  • Young age
  • RVH, pulmonary hypertension, COPD, secundum ASD
  • Lateral MI (loss of lateral forces)
  • Left posterior fascicular block (LPFB); diagnostic criteria:
    • right axis deviation > +100 degrees
    • leads II, III, aVF ­ but start with a narrow Q (qR)
    • leads I and aVL ¯ but start with a small r (rS)
    • all other causes of right axis deviation have been excluded
    • (isolated LPFB is exceedingly rare; it is a combined clinical and ECG diagnosis)