• Normal and Abnormal Heart Axis
• ECG and Right Axis Deviation
• Causes of Right Axis Deviation

Normal and Abnormal Heart Axis

• Normal (Intermediate) heart axis vector points between -30° and +90° (yellow)
• Right Axis Deviation vector points between +90° and +180° (green)
• Left Axis Deviation vector points between -30° and -90° (red)
• Extreme Axis Deviation vector points between -90° and +180° (blue)

Normal (Intermediate) Heart Axis

• If leads I and aVF are positive
• Then the vector points to the lower left quadrant (0° to 90°) and the axis is normal
• If lead I is positive and aVF is negative
• Then the vector points to the upper left quadrant (0° to -90°)
• Lead aVL (-30°) is the boundary
• between the normal axis and left axis deviation
• Lead II is perpendicular to lead aVL
• According to the biphasic QRS in lead II, it is determined whether it is a normal axis or left axis deviation

Causes of Right Axis Deviation

• Right Ventricular Hypertrophy
• Pulmonary Embolism (Acute Right Heart Overload)
• Lateral STEMI
• Chronic Obstructive Pulmonary Disease (COPD)
• Hyperkalemia
• Tricyclic Antidepressants (Intoxication)
• WPW Syndrome
• Dextrocardia
• Left Posterior Hemiblock
• Ventricular Extrasystole
• Normal Variant in Children
• Vertical Heart Position (Slim and Tall Patients)

Right Axis Deviation

• Right Axis Deviation
• Lead I is negative
• Lead aVF is positive
• Acute Pulmonary Embolism
• Negative T waves (V1-V5)
• Clockwise heart rotation (S in V6)
• The patient had pulmonary hypertension on echocardiography

Right Axis Deviation

• Right Axis Deviation
• Lead I is negative
• Lead aVF is positive
• Hyperkalemia (9.2 mmol/L)
• High peaked T waves
• Resemble the Eiffel Tower
• Consider hyperkalemia if T waves are higher than R waves (almost in all leads)
• Wide QRS complexes (0.2 s)
• In leads I and aVR, resemble a sinusoidal wave