Page 1 of 99
EKG Packet | FULL Rhythm Interpretation
+ Practice Strips & Answers | Master ECG
Fast 2026.
Q1. The P wave on an EKG represents:
A) Ventricular depolarization
B) Atrial depolarization
C) Ventricular repolarization
D) Atrial repolarization
✅ Answer: B
Rationale: The P wave represents atrial depolarization
(contraction). The QRS complex represents ventricular
depolarization. The T wave represents ventricular repolarization.
Atrial repolarization is not visible because it occurs during the
QRS and is masked.
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Q2. Which lead is considered the “rhythm strip” lead in a
standard 12-lead EKG?
A) Lead I
B) Lead II
C) Lead V5
D) Lead aVR
✅ Answer: B
Rationale: Lead II is commonly used for the rhythm strip because
it provides a clear view of the P wave and is aligned with the
cardiac axis, making arrhythmias easier to identify.
Q3. The normal duration of a QRS complex is:
A) <0.06 sec
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B) 0.06–0.10 sec
C) 0.10–0.12 sec
D) >0.12 sec
✅ Answer: B
Rationale: Normal QRS duration is 0.06–0.10 seconds (60–
100 ms). A QRS ≥0.12 seconds indicates intraventricular
conduction delay (bundle branch block or ventricular rhythm).
Q4. The PR interval is measured from the:
A) Beginning of the P wave to the beginning of the QRS
complex
B) End of the P wave to the end of the QRS
C) Beginning of the QRS to the end of the T wave
D) Beginning of the P wave to the end of the T wave
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✅ Answer: A
Rationale: The PR interval includes atrial depolarization plus the
conduction delay through the AV node. It begins at the start of
the P wave and ends at the start of the QRS complex.
Q5. The normal PR interval duration is:
A) 0.08–0.12 sec
B) 0.12–0.20 sec
C) 0.20–0.30 sec
D) >0.30 sec
✅ Answer: B
Rationale: Normal PR interval is 0.12–0.20 seconds (3 to 5 small
boxes at standard speed). A PR interval >0.20 seconds indicates
first-degree AV block.
EKG Packet | FULL Rhythm Interpretation
+ Practice Strips & Answers | Master ECG
Fast 2026.
Q1. The P wave on an EKG represents:
A) Ventricular depolarization
B) Atrial depolarization
C) Ventricular repolarization
D) Atrial repolarization
✅ Answer: B
Rationale: The P wave represents atrial depolarization
(contraction). The QRS complex represents ventricular
depolarization. The T wave represents ventricular repolarization.
Atrial repolarization is not visible because it occurs during the
QRS and is masked.
,Page 2 of 99
Q2. Which lead is considered the “rhythm strip” lead in a
standard 12-lead EKG?
A) Lead I
B) Lead II
C) Lead V5
D) Lead aVR
✅ Answer: B
Rationale: Lead II is commonly used for the rhythm strip because
it provides a clear view of the P wave and is aligned with the
cardiac axis, making arrhythmias easier to identify.
Q3. The normal duration of a QRS complex is:
A) <0.06 sec
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B) 0.06–0.10 sec
C) 0.10–0.12 sec
D) >0.12 sec
✅ Answer: B
Rationale: Normal QRS duration is 0.06–0.10 seconds (60–
100 ms). A QRS ≥0.12 seconds indicates intraventricular
conduction delay (bundle branch block or ventricular rhythm).
Q4. The PR interval is measured from the:
A) Beginning of the P wave to the beginning of the QRS
complex
B) End of the P wave to the end of the QRS
C) Beginning of the QRS to the end of the T wave
D) Beginning of the P wave to the end of the T wave
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✅ Answer: A
Rationale: The PR interval includes atrial depolarization plus the
conduction delay through the AV node. It begins at the start of
the P wave and ends at the start of the QRS complex.
Q5. The normal PR interval duration is:
A) 0.08–0.12 sec
B) 0.12–0.20 sec
C) 0.20–0.30 sec
D) >0.30 sec
✅ Answer: B
Rationale: Normal PR interval is 0.12–0.20 seconds (3 to 5 small
boxes at standard speed). A PR interval >0.20 seconds indicates
first-degree AV block.
