Home /

Left Axis Deviation

Left axis deviation

ECG and Left Axis Deviation

• The vector points to the upper left quadrant (red)
• Lead I is positive
• Lead aVF is negative
• Lead II is predominantly negative

Left Axis Deviation

• The vector points to the upper left quadrant
• Lead I is positive and aVF is negative
• Negative QRS in lead II
• The vector points away from lead II
• Equiphase QRS in aVR
• The vector is perpendicular to lead aVR
• Deepest S wave in lead III
• The vector axis is -60°

Left Axis Deviation

• Left Axis Deviation
• Lead I is positive
• Lead aVF is negative
• Lead II is predominantly negative
• Left Anterior Fascicular Block
• Left Axis Deviation
• Narrow QRS complexes < 0.12s

Left Axis Deviation

• Left Axis Deviation
• Lead I is positive
• Lead aVF is negative
• Lead II is predominantly negative
• Left Ventricular Hypertrophy
• Giant S and R waves in the precordial leads, extending into adjacent leads
• Positive Sokolow Index
• S(V1/2) + R(V5/6) ≥ 35mm
• Prolonged R wave time (V6) ≥ 50ms
• Definitive diagnosis is made using echocardiography

Left Axis Deviation

• Left Axis Deviation
• Lead I is positive
• Lead aVF is negative
• Lead II is predominantly negative
• WPW Syndrome Type B (Intermittent)
• Delta wave
• Negative QRS in V1 (Kent bundle is in the right atrium)