EKG: Axis Deviations

Between what degrees will you find the normal QRS?

+90 to 0

If the QRS in positive in both leads I and aVF

what will the QRS axis be?

How else can Direction of mean vector be said?

Mean electrical axis

In what direction does the mean vector point for depolarization?

• Left
• Inferior

In what lead will you find a normal QRS?

II

Between what degrees will you find Right axis deviation?

+90 and +180

What are the characteristics for Right axis deviation?

• Lead I: Negative QRS
• Lead aVF: Positive QRS

What are some possible causes for Right axis deviation?

• Right Ventricular Hypertrophy (RVH)
• Chronic lung disease (COPD)
• Lateral myocardial infarction (MI
• Pulmonary embolism (acute RV strain)
• Left posterior hemiblock

Between what degrees will you find Extreme Right axis deviation?

negative 90 and +180

What is Extreme Right axis deviation also known as?

• Northwest axis
• Superior axis

What are some characteristics of Northwest axis deviation?

• Lead I: Negative QRS
• Lead aVF: Negative QRS

What are some possible causes of Northwest axis deviation?

• Severe Right ventricular hypertrophy
• Ventricular rhythms
• Hyperkalemia

In what population is Right axis deviation very common?

• Pediatrics
• Vertically orientated hearts: Tall

Between what degrees will you find Left axis deviation?

negative 90 and 0

What are the characteristics of Left axis deviation?

• Lead I: Positive QRS
• Lead aVF: Negative QRS

What are some possible causes of Left axis deviation?

• Left ventricular hypertrophy

from hypertension

• Inferior myocardial infarction
• L bundle branch block
• L anterior fasicular hemiblock

In what population will you see Left axis deviation more often?

Short and stout

What leads are you looking at to determine axis deviation?

• Lead I
• Lead aVF