Einthoven's triangle

Causes of left axis deviation (LAD)

 left anterior hemiblock

 left bundle branch block

 Wolff‐Parkinson‐White syndrome* ‐  right‐sided accessory pathway

 hyperkalaemia

 congenital: ostium primum ASD, tricuspid atresia

 minor LAD in obese people

Causes of right axis deviation (RAD)

 right ventricular hypertrophy

 left posterior hemiblock

 chronic lung disease

 pulmonary embolism

 ostium secundum ASD

 Wolff‐Parkinson‐White syndrome* ‐  left‐sided accessory pathway

 normal in infant < 1 years old

 minor RAD in tall people

normal variants in an athlete:

 sinus bradycardia

 junctional rhythm