AXIS CERTIFICATION EXAM QUESTIONS WITH
COMPLETE SOLUTIONS
Question 1
The normal cardiac axis in adults is between:
A. 0° and +90°
B. –30° and +90°
C. –30° and +110°
D. 0° and +110°
Answer: B — –30° and +90°
Rationale: The normal QRS axis in adults ranges from –30° to
+90° (some sources –30° to +100°). Left axis deviation is ≤ –
30°, right axis deviation is ≥ +90° to +100°.
Question 2
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Which lead pair is most commonly used to quickly estimate
the QRS axis?
A. Leads I and II
B. Leads I and aVF
C. Leads II and III
D. Leads aVR and aVL
Answer: B — Leads I and aVF
Rationale: The quadrant approach uses lead I (right/left) and
lead aVF (up/down) to rapidly determine axis quadrant.
Question 3
If the QRS complex is predominantly positive (upright) in lead
I and predominantly positive in lead aVF, the axis is:
A. Normal axis
B. Left axis deviation
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C. Right axis deviation
D. Extreme axis (–90° to ±180°)
Answer: A — Normal axis
Rationale: Lead I positive = axis to the left (0° to +90°). Lead
aVF positive = axis downward (0° to +180°). Intersection = 0°
to +90° = normal axis.
Question 4
If the QRS is positive in lead I but negative in lead aVF, the
axis is:
A. Normal axis
B. Left axis deviation
C. Right axis deviation
D. Extreme axis
Answer: B — Left axis deviation
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Rationale: Lead I positive = axis to the left. Lead aVF negative
= axis upward. Intersection = left axis deviation (0° to –90°).
Typically –30° to –90° is LAD.
Question 5
If the QRS is negative in lead I but positive in lead aVF, the
axis is:
A. Normal axis
B. Left axis deviation
C. Right axis deviation
D. Extreme axis
Answer: C — Right axis deviation
Rationale: Lead I negative = axis to the right (≥ +90° to
+180°). Lead aVF positive = axis downward. Intersection = right
axis deviation (+90° to +180°).