HOAG ECG EXAM UPDATED EXAM STYLE
QUESTIONS AND CORRECT ANSWERS
250 High Yield ECG/EKG Practice Questions • A, B, C, D Choices • Answer and Rationale Immediately After Each Question
Important: This is an original exam-preparation workbook. It emphasizes high-yield concepts associated with HOAG-style
ECG competency preparation, but it does not reproduce or claim to contain leaked/proprietary actual examination
questions.
Format: Questions are blue, answer choices are black, correct answers are green, and rationales are purple for rapid
review.
HOAG ECG Exam Prep • Original exam-style study material Page 1
, ECG Fundamentals & Measurements
1. What does ECG stand for?
A. Electrocardiogram
B. Echocardiographic graph
C. Electrocardiac gradient
D. Electrical cardiac gauge
Correct Answer: A. Electrocardiogram
Rationale: ECG is the standard abbreviation for electrocardiogram, a recording of cardiac electrical activity.
2. Which structure normally initiates the heartbeat?
A. AV node
B. SA node
C. Bundle of His
D. Purkinje fibers
Correct Answer: B. SA node
Rationale: The sinoatrial (SA) node normally serves as the heart's primary pacemaker.
3. The P wave primarily represents:
A. Ventricular depolarization
B. Atrial depolarization
C. Atrial repolarization
D. Ventricular repolarization
Correct Answer: B. Atrial depolarization
Rationale: The P wave reflects atrial depolarization.
4. The QRS complex primarily represents:
A. Atrial depolarization
B. Ventricular depolarization
C. Atrial repolarization
D. Ventricular relaxation
Correct Answer: B. Ventricular depolarization
Rationale: The QRS complex reflects ventricular depolarization.
5. The T wave represents:
A. Atrial depolarization
B. Ventricular depolarization
C. Ventricular repolarization
D. AV-node depolarization
Correct Answer: C. Ventricular repolarization
Rationale: The T wave represents ventricular repolarization.
6. The PR interval is measured from:
A. Start of P to end of T
B. Start of P to start of QRS
C. Start of QRS to end of T
D. End of P to start of T
Correct Answer: B. Start of P to start of QRS
Rationale: PR is measured from the beginning of the P wave to the beginning of the QRS complex.
7. A standard ECG is commonly recorded at a paper speed of:
A. 10 mm/s
B. 25 mm/s
HOAG ECG Exam Prep • Original exam-style study material Page 2
, C. 50 mm/s
D. 100 mm/s
Correct Answer: B. 25 mm/s
Rationale: The conventional standard paper speed is 25 mm/s unless another speed is specified.
8. At 25 mm/s, one small ECG box represents:
A. 0.02 s
B. 0.04 s
C. 0.10 s
D. 0.20 s
Correct Answer: B. 0.04 s
Rationale: At 25 mm/s, 1 mm equals 0.04 seconds.
9. At 25 mm/s, one large ECG box represents:
A. 0.04 s
B. 0.10 s
C. 0.20 s
D. 0.40 s
Correct Answer: C. 0.20 s
Rationale: A large box contains five small boxes, so 5 × 0.04 = 0.20 seconds.
10. A normal adult PR interval is approximately:
A. 0.04–0.08 s
B. 0.12–0.20 s
C. 0.24–0.32 s
D. 0.36–0.44 s
Correct Answer: B. 0.12–0.20 s
Rationale: A typical normal PR interval is 0.12–0.20 seconds.
11. Which ECG component is most useful for assessing ventricular depolarization time?
A. P wave
B. PR segment
C. QRS duration
D. T-wave amplitude
Correct Answer: C. QRS duration
Rationale: QRS duration reflects the time required for ventricular depolarization.
12. Which ECG component occurs after the QRS complex and reflects ventricular recovery?
A. P wave
B. T wave
C. PR interval
D. Q wave
Correct Answer: B. T wave
Rationale: The T wave represents ventricular repolarization.
13. Which lead is a bipolar limb lead?
A. aVR
B. aVL
C. Lead II
D. V4
Correct Answer: C. Lead II
Rationale: Leads I, II, and III are bipolar limb leads.
HOAG ECG Exam Prep • Original exam-style study material Page 3
, 14. Which group contains only augmented limb leads?
A. I, II, III
B. V1, V2, V3
C. aVR, aVL, aVF
D. V4, V5, V6
Correct Answer: C. aVR, aVL, aVF
Rationale: The augmented limb leads are aVR, aVL, and aVF.
15. Which leads are considered precordial leads?
A. I, II, III
B. aVR, aVL, aVF
C. V1–V6
D. I, aVR, V1
Correct Answer: C. V1–V6
Rationale: V1 through V6 are the six precordial (chest) leads.
16. A 12-lead ECG provides how many electrical views of the heart?
A. 6
B. 8
C. 10
D. 12
Correct Answer: D. 12
Rationale: The standard 12-lead ECG provides 12 electrical views.
17. Which interval includes both ventricular depolarization and repolarization?
A. PR
B. QRS
C. QT
D. RR
Correct Answer: C. QT
Rationale: The QT interval spans ventricular depolarization through repolarization.
18. The isoelectric line is best described as the:
A. Baseline reference
B. Peak of the R wave
C. End of the T wave
D. Start of the P wave
Correct Answer: A. Baseline reference
Rationale: The isoelectric line is the ECG baseline used as a reference for segment displacement.
19. A wide QRS generally suggests:
A. Delayed ventricular conduction or ventricular origin
B. Normal atrial conduction
C. Shortened atrial depolarization
D. Only sinus bradycardia
Correct Answer: A. Delayed ventricular conduction or ventricular origin
Rationale: A widened QRS can reflect intraventricular conduction delay or a ventricular-origin rhythm.
20. Which ECG finding is most directly associated with atrial depolarization?
A. P wave
B. Q wave
C. ST segment
HOAG ECG Exam Prep • Original exam-style study material Page 4
QUESTIONS AND CORRECT ANSWERS
250 High Yield ECG/EKG Practice Questions • A, B, C, D Choices • Answer and Rationale Immediately After Each Question
Important: This is an original exam-preparation workbook. It emphasizes high-yield concepts associated with HOAG-style
ECG competency preparation, but it does not reproduce or claim to contain leaked/proprietary actual examination
questions.
Format: Questions are blue, answer choices are black, correct answers are green, and rationales are purple for rapid
review.
HOAG ECG Exam Prep • Original exam-style study material Page 1
, ECG Fundamentals & Measurements
1. What does ECG stand for?
A. Electrocardiogram
B. Echocardiographic graph
C. Electrocardiac gradient
D. Electrical cardiac gauge
Correct Answer: A. Electrocardiogram
Rationale: ECG is the standard abbreviation for electrocardiogram, a recording of cardiac electrical activity.
2. Which structure normally initiates the heartbeat?
A. AV node
B. SA node
C. Bundle of His
D. Purkinje fibers
Correct Answer: B. SA node
Rationale: The sinoatrial (SA) node normally serves as the heart's primary pacemaker.
3. The P wave primarily represents:
A. Ventricular depolarization
B. Atrial depolarization
C. Atrial repolarization
D. Ventricular repolarization
Correct Answer: B. Atrial depolarization
Rationale: The P wave reflects atrial depolarization.
4. The QRS complex primarily represents:
A. Atrial depolarization
B. Ventricular depolarization
C. Atrial repolarization
D. Ventricular relaxation
Correct Answer: B. Ventricular depolarization
Rationale: The QRS complex reflects ventricular depolarization.
5. The T wave represents:
A. Atrial depolarization
B. Ventricular depolarization
C. Ventricular repolarization
D. AV-node depolarization
Correct Answer: C. Ventricular repolarization
Rationale: The T wave represents ventricular repolarization.
6. The PR interval is measured from:
A. Start of P to end of T
B. Start of P to start of QRS
C. Start of QRS to end of T
D. End of P to start of T
Correct Answer: B. Start of P to start of QRS
Rationale: PR is measured from the beginning of the P wave to the beginning of the QRS complex.
7. A standard ECG is commonly recorded at a paper speed of:
A. 10 mm/s
B. 25 mm/s
HOAG ECG Exam Prep • Original exam-style study material Page 2
, C. 50 mm/s
D. 100 mm/s
Correct Answer: B. 25 mm/s
Rationale: The conventional standard paper speed is 25 mm/s unless another speed is specified.
8. At 25 mm/s, one small ECG box represents:
A. 0.02 s
B. 0.04 s
C. 0.10 s
D. 0.20 s
Correct Answer: B. 0.04 s
Rationale: At 25 mm/s, 1 mm equals 0.04 seconds.
9. At 25 mm/s, one large ECG box represents:
A. 0.04 s
B. 0.10 s
C. 0.20 s
D. 0.40 s
Correct Answer: C. 0.20 s
Rationale: A large box contains five small boxes, so 5 × 0.04 = 0.20 seconds.
10. A normal adult PR interval is approximately:
A. 0.04–0.08 s
B. 0.12–0.20 s
C. 0.24–0.32 s
D. 0.36–0.44 s
Correct Answer: B. 0.12–0.20 s
Rationale: A typical normal PR interval is 0.12–0.20 seconds.
11. Which ECG component is most useful for assessing ventricular depolarization time?
A. P wave
B. PR segment
C. QRS duration
D. T-wave amplitude
Correct Answer: C. QRS duration
Rationale: QRS duration reflects the time required for ventricular depolarization.
12. Which ECG component occurs after the QRS complex and reflects ventricular recovery?
A. P wave
B. T wave
C. PR interval
D. Q wave
Correct Answer: B. T wave
Rationale: The T wave represents ventricular repolarization.
13. Which lead is a bipolar limb lead?
A. aVR
B. aVL
C. Lead II
D. V4
Correct Answer: C. Lead II
Rationale: Leads I, II, and III are bipolar limb leads.
HOAG ECG Exam Prep • Original exam-style study material Page 3
, 14. Which group contains only augmented limb leads?
A. I, II, III
B. V1, V2, V3
C. aVR, aVL, aVF
D. V4, V5, V6
Correct Answer: C. aVR, aVL, aVF
Rationale: The augmented limb leads are aVR, aVL, and aVF.
15. Which leads are considered precordial leads?
A. I, II, III
B. aVR, aVL, aVF
C. V1–V6
D. I, aVR, V1
Correct Answer: C. V1–V6
Rationale: V1 through V6 are the six precordial (chest) leads.
16. A 12-lead ECG provides how many electrical views of the heart?
A. 6
B. 8
C. 10
D. 12
Correct Answer: D. 12
Rationale: The standard 12-lead ECG provides 12 electrical views.
17. Which interval includes both ventricular depolarization and repolarization?
A. PR
B. QRS
C. QT
D. RR
Correct Answer: C. QT
Rationale: The QT interval spans ventricular depolarization through repolarization.
18. The isoelectric line is best described as the:
A. Baseline reference
B. Peak of the R wave
C. End of the T wave
D. Start of the P wave
Correct Answer: A. Baseline reference
Rationale: The isoelectric line is the ECG baseline used as a reference for segment displacement.
19. A wide QRS generally suggests:
A. Delayed ventricular conduction or ventricular origin
B. Normal atrial conduction
C. Shortened atrial depolarization
D. Only sinus bradycardia
Correct Answer: A. Delayed ventricular conduction or ventricular origin
Rationale: A widened QRS can reflect intraventricular conduction delay or a ventricular-origin rhythm.
20. Which ECG finding is most directly associated with atrial depolarization?
A. P wave
B. Q wave
C. ST segment
HOAG ECG Exam Prep • Original exam-style study material Page 4
