Basic Arrhythmia Sentara Test Prep: ECG Rhythm
Recognition Practice Questions & Rationales
This specialized clinical preparation resource provides targeted practice questions,
verified answers, and detailed telemetry rationales designed for the Sentara Healthcare
Basic Arrhythmia competency assessment. It covers core electrocardiogram (ECG)
tracking capabilities, including calculating heart rates, measuring cardiac intervals, and
identifying lethal dysrhythmias such as ventricular fibrillation and various heart blocks.
Critical care nurses, telemetry technicians, and allied health professionals will master
rhythm strip analysis and immediate nursing intervention protocols to ensure clinical
safety and pass their mandatory employment screening.
Section 1: ECG Basics & Measurements (Questions 1-15)
Question 1
What does the P wave represent on an ECG tracing?
A. Ventricular depolarization
B. Atrial depolarization
C. Ventricular repolarization
D. Atrial repolarization
Correct Answer: B) Atrial depolarization
,Rationale: The P wave represents atrial depolarization, which corresponds to atrial
contraction. It reflects the electrical impulse spreading through the atria from the SA node.
Question 2
What does the QRS complex represent?
A. Atrial depolarization
B. Ventricular repolarization
C. Ventricular depolarization
D. Atrial repolarization
Correct Answer: C) Ventricular depolarization
Rationale: The QRS complex represents ventricular depolarization, which corresponds to
ventricular contraction. This is the largest waveform on the ECG because the ventricles
have more muscle mass than the atria.
Question 3
What does the T wave represent?
A. Atrial depolarization
B. Ventricular depolarization
C. Ventricular repolarization
D. Atrial repolarization
Correct Answer: C) Ventricular repolarization
,Rationale: The T wave represents ventricular repolarization, which is the electrical recovery
of the ventricles after depolarization.
Question 4
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
Correct Answer: B) 0.12-0.20 seconds
Rationale: The normal PR interval is 0.12-0.20 seconds (3-5 small squares). It represents
the time from the start of atrial depolarization to the start of ventricular depolarization.
Question 5
What is the normal duration of the QRS complex in an adult?
A. 0.04-0.06 seconds
B. 0.06-0.12 seconds
C. 0.12-0.20 seconds
D. 0.20-0.32 seconds
Correct Answer: B) 0.06-0.12 seconds
, Rationale: The normal QRS duration is 0.06-0.12 seconds (1.5-3 small squares). A QRS
>0.12 seconds indicates a bundle branch block or ventricular origin of the impulse.
Question 6
What is the normal duration of the QT interval?
A. 0.20-0.32 seconds
B. 0.32-0.44 seconds
C. 0.44-0.52 seconds
D. 0.12-0.20 seconds
Correct Answer: B) 0.32-0.44 seconds
Rationale: The normal QT interval is 0.32-0.44 seconds and varies with heart rate. It
represents ventricular depolarization and repolarization.
Question 7
What is the length of each small square on standard ECG paper?
A. 0.02 seconds
B. 0.04 seconds
C. 0.20 seconds
D. 0.40 seconds
Correct Answer: B) 0.04 seconds
Recognition Practice Questions & Rationales
This specialized clinical preparation resource provides targeted practice questions,
verified answers, and detailed telemetry rationales designed for the Sentara Healthcare
Basic Arrhythmia competency assessment. It covers core electrocardiogram (ECG)
tracking capabilities, including calculating heart rates, measuring cardiac intervals, and
identifying lethal dysrhythmias such as ventricular fibrillation and various heart blocks.
Critical care nurses, telemetry technicians, and allied health professionals will master
rhythm strip analysis and immediate nursing intervention protocols to ensure clinical
safety and pass their mandatory employment screening.
Section 1: ECG Basics & Measurements (Questions 1-15)
Question 1
What does the P wave represent on an ECG tracing?
A. Ventricular depolarization
B. Atrial depolarization
C. Ventricular repolarization
D. Atrial repolarization
Correct Answer: B) Atrial depolarization
,Rationale: The P wave represents atrial depolarization, which corresponds to atrial
contraction. It reflects the electrical impulse spreading through the atria from the SA node.
Question 2
What does the QRS complex represent?
A. Atrial depolarization
B. Ventricular repolarization
C. Ventricular depolarization
D. Atrial repolarization
Correct Answer: C) Ventricular depolarization
Rationale: The QRS complex represents ventricular depolarization, which corresponds to
ventricular contraction. This is the largest waveform on the ECG because the ventricles
have more muscle mass than the atria.
Question 3
What does the T wave represent?
A. Atrial depolarization
B. Ventricular depolarization
C. Ventricular repolarization
D. Atrial repolarization
Correct Answer: C) Ventricular repolarization
,Rationale: The T wave represents ventricular repolarization, which is the electrical recovery
of the ventricles after depolarization.
Question 4
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
Correct Answer: B) 0.12-0.20 seconds
Rationale: The normal PR interval is 0.12-0.20 seconds (3-5 small squares). It represents
the time from the start of atrial depolarization to the start of ventricular depolarization.
Question 5
What is the normal duration of the QRS complex in an adult?
A. 0.04-0.06 seconds
B. 0.06-0.12 seconds
C. 0.12-0.20 seconds
D. 0.20-0.32 seconds
Correct Answer: B) 0.06-0.12 seconds
, Rationale: The normal QRS duration is 0.06-0.12 seconds (1.5-3 small squares). A QRS
>0.12 seconds indicates a bundle branch block or ventricular origin of the impulse.
Question 6
What is the normal duration of the QT interval?
A. 0.20-0.32 seconds
B. 0.32-0.44 seconds
C. 0.44-0.52 seconds
D. 0.12-0.20 seconds
Correct Answer: B) 0.32-0.44 seconds
Rationale: The normal QT interval is 0.32-0.44 seconds and varies with heart rate. It
represents ventricular depolarization and repolarization.
Question 7
What is the length of each small square on standard ECG paper?
A. 0.02 seconds
B. 0.04 seconds
C. 0.20 seconds
D. 0.40 seconds
Correct Answer: B) 0.04 seconds
