Question:medium
A left axis deviation of \(-30^\circ\) to \(-60^\circ\) on the ECG is seen in?
A left axis deviation of \(-30^\circ\) to \(-60^\circ\) on the ECG is seen in?
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Axis more negative than \(-30^\circ\) points to the left ventricle being enlarged.
Updated On: Jun 24, 2026
- Left ventricular hypertrophy
- Right ventricular hypertrophy
- Aortic stenosis
- Left atrial enlargement
Show Solution
The Correct Option is A
Solution and Explanation
Step 1: Define the boundaries. A healthy frontal-plane QRS axis sits between $-30^\circ$ and $+90^\circ$; readings beyond $-30^\circ$ toward the upper-left signify left axis deviation.
Step 2: When the left ventricle thickens, the bulk of depolarizing muscle is on the left and superior side, dragging the average electrical vector into the $-30^\circ$ to $-60^\circ$ zone.
Step 3: The classic triad producing this superior-left axis is left ventricular hypertrophy, left anterior fascicular (hemiblock) block, and inferior wall infarction.
Step 4: By contrast, right ventricular hypertrophy pulls the axis rightward, left atrial enlargement is a P-wave finding, and aortic stenosis is only an indirect association, so left ventricular hypertrophy is the best fit.
\[\boxed{\text{Left ventricular hypertrophy}}\]
Step 2: When the left ventricle thickens, the bulk of depolarizing muscle is on the left and superior side, dragging the average electrical vector into the $-30^\circ$ to $-60^\circ$ zone.
Step 3: The classic triad producing this superior-left axis is left ventricular hypertrophy, left anterior fascicular (hemiblock) block, and inferior wall infarction.
Step 4: By contrast, right ventricular hypertrophy pulls the axis rightward, left atrial enlargement is a P-wave finding, and aortic stenosis is only an indirect association, so left ventricular hypertrophy is the best fit.
\[\boxed{\text{Left ventricular hypertrophy}}\]
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