ECG: Axis Deviation

Key points

• Left axis deviation: left anterior hemiblock · left bundle branch block · Wolff-Parkinson-White syndrome with a right-sided accessory pathway · hyperkalaemia · congenital (ostium primum ASD, tricuspid atresia) · minor LAD in obese people
• Right axis deviation: right ventricular hypertrophy · left posterior hemiblock · chronic lung disease → cor pulmonale · pulmonary embolism · ostium secundum ASD · Wolff-Parkinson-White syndrome with a left-sided accessory pathway · normal in infants < 1 year · minor RAD in tall people
• In the majority of cases, or in a question without qualification, Wolff-Parkinson-White syndrome is associated with left axis deviation
• WPW: short PR interval and a wide QRS complex with a slurred upstroke (delta wave); axis deviation depends on the position of the accessory pathway

Decision points in this pathway

• Left axis deviation present?

The full step-by-step algorithm, including what to do at each branch, opens in the app for approved members.