see also:

• The basics of reading an ECG
• left axis deviation (LAD)

• right axis deviation is an ECG finding where the mean frontal QRS axis is between +90 deg to +180deg
• the normal QRS axis is -30deg to +90deg

• normal in children
  • may persistent into early adulthood, particularly if patient is tall and thin
• electrode misplacement
• right ventricular hypertrophy (RVH)
  • RVH may exist without RAD, while combined RVH and LVH may also give a normal axis or even LAD
  • when RAD occurs in RVH, the axis is usually > +110deg
• lateral wall MI
  • loss of leftward forces due to infarction result in rightward shift in QRS axis, owing to a dominant Q or QS in lead I
  • confirmatory evidence is presence of Q waves in V5-6.
• left posterior fascicular block
  • delayed activation of post/inf. part of left ventricle causes rightward shift in QRS axis
  • presence of RA enlargement suggests RVH rather than LPFB (LPHB)
  • presence of inf. or post. MI suggests LPFB rather than RVH
• chronic obstructive pulmonary disease (COPD)
  • may give an axis of +90deg to +110deg even in absence of pulmonary hypertension
• ectopic ventricular rhythms originating in RV
  • may give a Left Bundle Branch Block (LBBB) pattern but with RAD
• dextrocardia
  • may give an extreme axis deviation (-90deg to -180deg) or RAD
• limb lead misplacement