II. Interpretation: Axis Determination (Method 1)
 Images: EKG Axis
 Check lead I (0 degrees)
 QRS positive (predominately up)
 Vector points to patient's Left
 Correlates with right half of axis circle (12:00 to 6:00 on clockface)
 QRS negative (predominately down)
 Vector points to patient's Right (6:00 to 12:00 on clockface)
 Correlates with left half of axis circle (always Right Axis Deviation)
 QRS positive (predominately up)
 Check lead aVF (90 degrees)
 QRS positive (predominately up)
 Vector points to bottom half of axis circle (3:00 to 9:00 on clockface)
 QRS negative (predominately down)
 Vector points to upper half of axis circle (Left Axis Deviation if 30 to 90 degrees, or 12:00 to 2:00)
 QRS positive (predominately up)
 Interpretation
 Indeterminate: Extreme Right Axis Deviation
 Lead I: Negative QRS
 Lead aVF: Negative QRS
 Right Axis Deviation
 Lead I: Negative QRS
 Lead aVF: Positive QRS
 Normal range
 Lead I: Positive QRS
 Lead aVF: Positive QRS
 Left Axis Deviation
 Lead I: Positive QRS
 Lead aVF: Negative QRS (normal if 30 to 0 degrees, 2:00 to 3:00 on clockface)
 Indeterminate: Extreme Right Axis Deviation
III. Interpretation: Axis Determination (Method 2)
 Select Isoelectric lead from limb and augmented leads
 Isoelectric lead averages to baseline
 Positive deflection equals negative deflection
 Identify isoelectric lead on axis circle
 Lead with most symmetric voltage (as much positive QRS voltage as negative QRS voltage)
 Choose lead that is perpendicular to isoelectric lead
 Use Lead I and aVF to determine quadrant
 Read perpendicular lead's degrees off axis circle

Extreme Right Axis Deviation (90 to 180, negative in lead I and negative in lead avF)
 Most Isoelectric I (avF is perpendicular): 90 (12:00)
 Most Isoelectric avL (II is perpendicular): 120 (11:00)
 Most Isoelectric III (avR is perpendicular): 150 (10:00)
 Most Isoelectric avF (I is perpendicular): 180 (9:00)

Right Axis Deviation (+180 to +90, negative in lead I and positive in lead avF)
 Most Isoelectric avF (I is perpendicular): +180 (9:00)
 Most Isoelectric II (avL is perpendicular): +150 (8:00)
 Most Isoelectric avR (III is perpendicular): +120 (7:00)
 Most Isoelectric I (avF is perpendicular): +90 (6:00)

Left Axis Deviation (90 to 30, positive in lead I and negative in lead avF)
 Most Isoelectric I (avF is perpendicular): 90 (12:00)
 Most Isoelectric avR (III is perpendicular): 60 (1:00)
 Most Isoelectric II (avL is perpendicular): 30 (2:00)
 Normal Axis (+90 to 30, positive in lead I and positive in lead avF)
 Most Isoelectric avF (I is perpendicular): 0 (3:00)
 Most Isoelectric III (avR is perpendicular): +30 (4:00)
 Most Isoelectric avL (II is perpendicular): +60 (5:00)
 Most Isoelectric I (avF is perpendicular): +90 (6:00)