Left axis deviation can be associated with which conditions?

Left axis deviation can be associated with which conditions?

• A. Left ventricular hypertrophy and hypertension
• B. Right ventricular hypertrophy
• C. Pulmonary embolism
• D. Hyperkalemia

Answer: (A)

Left axis deviation means the overall QRS electrical vector is directed more toward the left side of the heart. This occurs when the left ventricle becomes the dominant pumping force, typically because its mass has increased. Chronic hypertension is a common driver of this process: the heart adapts to higher afterload by hypertrophying the left ventricle, which strengthens leftward electrical forces and shifts the mean QRS axis to the left. So, conditions that lead to left ventricular hypertrophy, such as hypertension, are strongly associated with left axis deviation.

Right ventricular hypertrophy tends to push the axis to the right, not left. Pulmonary embolism often causes right heart strain and right axis deviation. Hyperkalemia alters conduction and the appearance of waves on the ECG but does not specifically produce left axis deviation.