BASIC ARRHYTHMIA Sentara Test Questions &
Answer Bank (2026/2027 Update) | 100% Verified
Pass Guide
1. What does the P wave represent on an ECG?
A. Ventricular depolarization
B. Atrial depolarization
C. Ventricular repolarization
D. Atrial repolarization
Answer: B
Rationale: The P wave represents atrial depolarization (contraction). It reflects the
electrical impulse spreading through the atria from the SA node .
2. What does the QRS complex represent?
A. Atrial depolarization
B. Ventricular repolarization
C. Ventricular depolarization
D. Purkinje fiber repolarization
Answer: C
Rationale: The QRS complex represents ventricular depolarization (contraction). This is
the largest waveform on the ECG .
3. What is the normal duration of the PR interval in an adult?
A. 0.06–0.10 seconds
B. 0.12–0.20 seconds
C. 0.20–0.32 seconds
D. 0.32–0.44 seconds
Answer: B
Rationale: The normal PR interval length is 0.12–0.20 seconds. It represents the time
from the start of atrial depolarization to the start of ventricular depolarization .
,4. What is the normal duration of the QRS complex?
A. 0.12–0.20 seconds
B. 0.06–0.12 seconds
C. 0.04–0.06 seconds
D. 0.20–0.32 seconds
Answer: B
Rationale: The normal QRS duration is 0.06–0.12 seconds. A QRS >0.12 seconds
indicates a bundle branch block or ventricular origin .
5. What is the normal duration of the QT interval?
A. 0.12–0.20 seconds
B. 0.06–0.12 seconds
C. 0.32–0.44 seconds
D. 0.44–0.52 seconds
Answer: C
Rationale: The normal QT interval is 0.32–0.44 seconds. It represents ventricular
depolarization and repolarization. Prolonged QT intervals (often caused by medications)
increase the risk for Torsades de Pointes .
6. What is the length of a small square on EKG paper?
A. 0.02 seconds
B. 0.04 seconds
C. 0.20 seconds
D. 0.50 seconds
Answer: B
Rationale: EKG paper runs at a standard speed of 25 mm/second. Each small 1 mm box
equals 0.04 seconds, while the larger heavy-lined box (5 small boxes) equals 0.20
seconds .
,7. What is the length of a regular (large) square on EKG paper?
A. 0.04 seconds
B. 0.10 seconds
C. 0.20 seconds
D. 1.0 seconds
Answer: C
Rationale: The large box is used for rapid heart rate calculations (e.g., counting the
number of large boxes between R waves to determine rate). Five large boxes equals 1
second .
8. How many large boxes equal 1 second?
A. 1
B. 3
C. 5
D. 10
Answer: C
Rationale: Five large boxes (each 0.20 seconds) equals 1 second. This is used for rate
calculation .
9. What are the 5 steps to EKG Interpretation?
A. Look for P waves → Measure PR Interval → Measure QRS → Identify Rhythm → Count
Rate
B. Look for QRS → Measure QT → Measure PR → Identify Rhythm → Count Rate
C. Identify Rhythm → Count Rate → Measure QRS → Measure PR → Look for P waves
D. Count Rate → Identify Rhythm → Measure QRS → Measure QT → Look for P waves
Answer: A
Rationale: This systematic approach ensures no critical detail is missed: 1) Look for P
waves; 2) Measure PR Interval; 3) Measure QRS; 4) Identify Rhythm as regular or
irregular; 5) Count Rate. The QT interval is important to measure as many medications
can affect its duration; however, this does not alter the primary interpretation .
, 10. What does the T wave represent?
A. Atrial depolarization
B. Ventricular depolarization
C. Ventricular repolarization
D. Atrial repolarization
Answer: C
Rationale: The T wave represents ventricular repolarization, which is the recovery phase
of the ventricles .
11. What do U waves represent?
A. Atrial depolarization
B. Ventricular depolarization
C. Repolarization of the Purkinje fibers
D. AV node conduction
Answer: C
Rationale: U waves represent repolarization of the Purkinje fibers .
12. What is the inherent rate of the SA node?
A. 20–40 bpm
B. 40–60 bpm
C. 60–100 bpm
D. 100–150 bpm
Answer: C
Rationale: The SA node is the primary pacemaker with an inherent rate of 60–100 bpm .
13. What is the inherent rate of the AV node?
A. 20–40 bpm
B. 40–60 bpm
C. 60–100 bpm
D. 100–150 bpm
Answer Bank (2026/2027 Update) | 100% Verified
Pass Guide
1. What does the P wave represent on an ECG?
A. Ventricular depolarization
B. Atrial depolarization
C. Ventricular repolarization
D. Atrial repolarization
Answer: B
Rationale: The P wave represents atrial depolarization (contraction). It reflects the
electrical impulse spreading through the atria from the SA node .
2. What does the QRS complex represent?
A. Atrial depolarization
B. Ventricular repolarization
C. Ventricular depolarization
D. Purkinje fiber repolarization
Answer: C
Rationale: The QRS complex represents ventricular depolarization (contraction). This is
the largest waveform on the ECG .
3. What is the normal duration of the PR interval in an adult?
A. 0.06–0.10 seconds
B. 0.12–0.20 seconds
C. 0.20–0.32 seconds
D. 0.32–0.44 seconds
Answer: B
Rationale: The normal PR interval length is 0.12–0.20 seconds. It represents the time
from the start of atrial depolarization to the start of ventricular depolarization .
,4. What is the normal duration of the QRS complex?
A. 0.12–0.20 seconds
B. 0.06–0.12 seconds
C. 0.04–0.06 seconds
D. 0.20–0.32 seconds
Answer: B
Rationale: The normal QRS duration is 0.06–0.12 seconds. A QRS >0.12 seconds
indicates a bundle branch block or ventricular origin .
5. What is the normal duration of the QT interval?
A. 0.12–0.20 seconds
B. 0.06–0.12 seconds
C. 0.32–0.44 seconds
D. 0.44–0.52 seconds
Answer: C
Rationale: The normal QT interval is 0.32–0.44 seconds. It represents ventricular
depolarization and repolarization. Prolonged QT intervals (often caused by medications)
increase the risk for Torsades de Pointes .
6. What is the length of a small square on EKG paper?
A. 0.02 seconds
B. 0.04 seconds
C. 0.20 seconds
D. 0.50 seconds
Answer: B
Rationale: EKG paper runs at a standard speed of 25 mm/second. Each small 1 mm box
equals 0.04 seconds, while the larger heavy-lined box (5 small boxes) equals 0.20
seconds .
,7. What is the length of a regular (large) square on EKG paper?
A. 0.04 seconds
B. 0.10 seconds
C. 0.20 seconds
D. 1.0 seconds
Answer: C
Rationale: The large box is used for rapid heart rate calculations (e.g., counting the
number of large boxes between R waves to determine rate). Five large boxes equals 1
second .
8. How many large boxes equal 1 second?
A. 1
B. 3
C. 5
D. 10
Answer: C
Rationale: Five large boxes (each 0.20 seconds) equals 1 second. This is used for rate
calculation .
9. What are the 5 steps to EKG Interpretation?
A. Look for P waves → Measure PR Interval → Measure QRS → Identify Rhythm → Count
Rate
B. Look for QRS → Measure QT → Measure PR → Identify Rhythm → Count Rate
C. Identify Rhythm → Count Rate → Measure QRS → Measure PR → Look for P waves
D. Count Rate → Identify Rhythm → Measure QRS → Measure QT → Look for P waves
Answer: A
Rationale: This systematic approach ensures no critical detail is missed: 1) Look for P
waves; 2) Measure PR Interval; 3) Measure QRS; 4) Identify Rhythm as regular or
irregular; 5) Count Rate. The QT interval is important to measure as many medications
can affect its duration; however, this does not alter the primary interpretation .
, 10. What does the T wave represent?
A. Atrial depolarization
B. Ventricular depolarization
C. Ventricular repolarization
D. Atrial repolarization
Answer: C
Rationale: The T wave represents ventricular repolarization, which is the recovery phase
of the ventricles .
11. What do U waves represent?
A. Atrial depolarization
B. Ventricular depolarization
C. Repolarization of the Purkinje fibers
D. AV node conduction
Answer: C
Rationale: U waves represent repolarization of the Purkinje fibers .
12. What is the inherent rate of the SA node?
A. 20–40 bpm
B. 40–60 bpm
C. 60–100 bpm
D. 100–150 bpm
Answer: C
Rationale: The SA node is the primary pacemaker with an inherent rate of 60–100 bpm .
13. What is the inherent rate of the AV node?
A. 20–40 bpm
B. 40–60 bpm
C. 60–100 bpm
D. 100–150 bpm
