This chart will help you quickly determine the direction of a patient's electrical axis. Observe the deflections of the QRS complexes in leads I and aV_F. Lead I indicates whether impulses are moving to the right or left, and lead aV_F indicates whether they're moving up or down. Then check the chart to determine whether the patient's axis is normal or has a left, right, or extreme right deviation.

• Normal axis: QRS-complex deflection is positive or upright in both leads.
• Left axis deviation: Lead I is upright and lead aV_F points down.
• Right axis deviation: Lead I points down and lead aV_F is upright.
• Extreme right axis deviation: Both waves point down.