What is the normal QRS axis range?

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Multiple Choice

What is the normal QRS axis range?

The QRS axis is the average direction of ventricular depolarization in the frontal plane. In a healthy heart, this mean axis falls between -30 degrees and +90 degrees. This range reflects the typical orientation of the heart’s depolarization vectors, usually directed downward and to the left, with some variation toward the right. If the axis is more negative than -30 degrees, that’s left axis deviation, which can be seen with conditions like left ventricular hypertrophy or certain conduction abnormalities. If the axis is more positive than +90 degrees, that’s right axis deviation, seen with things like COPD or pulmonary hypertension. The range -30° to +90° is the normal one, so that choice is correct.

The QRS axis is the average direction of ventricular depolarization in the frontal plane. In a healthy heart, this mean axis falls between -30 degrees and +90 degrees. This range reflects the typical orientation of the heart’s depolarization vectors, usually directed downward and to the left, with some variation toward the right.

If the axis is more negative than -30 degrees, that’s left axis deviation, which can be seen with conditions like left ventricular hypertrophy or certain conduction abnormalities. If the axis is more positive than +90 degrees, that’s right axis deviation, seen with things like COPD or pulmonary hypertension. The range -30° to +90° is the normal one, so that choice is correct.

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