Relias Dysrhythmia Basic exam verified with correct answers plus
rationales 2026/2027 version
1. What is the normal intrinsic rate of the sinoatrial (SA) node?
A. 20–40 beats/min
B. 40–60 beats/min
C. 60–100 beats/min
D. 100–150 beats/min
Rationale: The SA node is the heart's normal pacemaker and typically fires at approximately 60–
100 beats/min.
2. Which ECG component represents atrial depolarization?
A. QRS complex
B. T wave
C. P wave
D. ST segment
Rationale: The P wave represents electrical depolarization of the atria.
3. The QRS complex represents:
A. Atrial repolarization
B. Ventricular repolarization
C. Ventricular depolarization
D. SA-node firing only
Rationale: The QRS complex reflects depolarization of the ventricles.
4. The T wave represents:
A. Atrial depolarization
B. Ventricular depolarization
C. Ventricular repolarization
D. AV-node conduction
Rationale: The T wave represents ventricular repolarization.
5. A normal PR interval is generally:
A. 0.04–0.08 seconds
B. 0.12–0.20 seconds
,C. 0.24–0.30 seconds
D. 0.30–0.40 seconds
Rationale: A normal PR interval is approximately 0.12–0.20 seconds.
6. A normal QRS duration is generally:
A. 0.20–0.30 seconds
B. 0.16–0.20 seconds
C. Less than 0.12 seconds
D. Greater than 0.30 seconds
Rationale: A QRS duration under 0.12 seconds is generally considered narrow.
7. A rhythm with a rate of 52 beats/min, a regular rhythm, and normal P waves
before each QRS is most consistent with:
A. Sinus tachycardia
B. Atrial fibrillation
C. Sinus bradycardia
D. Ventricular fibrillation
Rationale: Sinus bradycardia has a sinus rhythm with a rate below 60 beats/min in adults.
8. A sinus rhythm with a rate of 118 beats/min is most consistent with:
A. Sinus bradycardia
B. Sinus tachycardia
C. Complete heart block
D. Ventricular standstill
Rationale: Sinus tachycardia is a sinus rhythm with an adult rate above 100 beats/min.
9. Which rhythm is characterized by an "irregularly irregular" ventricular
rhythm and absence of consistent P waves?
A. Sinus rhythm
B. Atrial flutter
C. Atrial fibrillation
D. First-degree AV block
Rationale: Atrial fibrillation produces chaotic atrial activity and an irregularly irregular
ventricular response.
10. Atrial flutter commonly produces which characteristic ECG finding?
, A. Wide QRS complexes only
B. Sawtooth flutter waves
C. Completely absent electrical activity
D. One P wave for every QRS with a prolonged PR
Rationale: Atrial flutter commonly produces organized atrial activity appearing as repetitive
sawtooth flutter waves.
11. Which rhythm is immediately life-threatening and requires rapid
intervention?
A. Sinus bradycardia without symptoms
B. First-degree AV block
C. Ventricular fibrillation
D. Sinus arrhythmia
Rationale: Ventricular fibrillation produces ineffective ventricular activity and results in cardiac
arrest.
12. A patient is unresponsive, not breathing normally, and has no pulse. The
monitor shows ventricular fibrillation. What is the priority?
A. Obtain a 12-lead ECG
B. Give oral medication
C. Begin CPR and defibrillate as soon as possible
D. Wait for the rhythm to convert spontaneously
Rationale: VF is a shockable cardiac-arrest rhythm. High-quality CPR and prompt defibrillation
are critical.
13. Which rhythm is also considered a shockable cardiac-arrest rhythm?
A. Asystole
B. Pulseless electrical activity
C. Pulseless ventricular tachycardia
D. Sinus bradycardia
Rationale: Pulseless ventricular tachycardia, like ventricular fibrillation, is treated with
defibrillation and CPR.
14. A patient has a wide-complex tachycardia at 180 beats/min with no palpable
pulse. This should be treated as:
A. Sinus tachycardia
B. Pulseless ventricular tachycardia
rationales 2026/2027 version
1. What is the normal intrinsic rate of the sinoatrial (SA) node?
A. 20–40 beats/min
B. 40–60 beats/min
C. 60–100 beats/min
D. 100–150 beats/min
Rationale: The SA node is the heart's normal pacemaker and typically fires at approximately 60–
100 beats/min.
2. Which ECG component represents atrial depolarization?
A. QRS complex
B. T wave
C. P wave
D. ST segment
Rationale: The P wave represents electrical depolarization of the atria.
3. The QRS complex represents:
A. Atrial repolarization
B. Ventricular repolarization
C. Ventricular depolarization
D. SA-node firing only
Rationale: The QRS complex reflects depolarization of the ventricles.
4. The T wave represents:
A. Atrial depolarization
B. Ventricular depolarization
C. Ventricular repolarization
D. AV-node conduction
Rationale: The T wave represents ventricular repolarization.
5. A normal PR interval is generally:
A. 0.04–0.08 seconds
B. 0.12–0.20 seconds
,C. 0.24–0.30 seconds
D. 0.30–0.40 seconds
Rationale: A normal PR interval is approximately 0.12–0.20 seconds.
6. A normal QRS duration is generally:
A. 0.20–0.30 seconds
B. 0.16–0.20 seconds
C. Less than 0.12 seconds
D. Greater than 0.30 seconds
Rationale: A QRS duration under 0.12 seconds is generally considered narrow.
7. A rhythm with a rate of 52 beats/min, a regular rhythm, and normal P waves
before each QRS is most consistent with:
A. Sinus tachycardia
B. Atrial fibrillation
C. Sinus bradycardia
D. Ventricular fibrillation
Rationale: Sinus bradycardia has a sinus rhythm with a rate below 60 beats/min in adults.
8. A sinus rhythm with a rate of 118 beats/min is most consistent with:
A. Sinus bradycardia
B. Sinus tachycardia
C. Complete heart block
D. Ventricular standstill
Rationale: Sinus tachycardia is a sinus rhythm with an adult rate above 100 beats/min.
9. Which rhythm is characterized by an "irregularly irregular" ventricular
rhythm and absence of consistent P waves?
A. Sinus rhythm
B. Atrial flutter
C. Atrial fibrillation
D. First-degree AV block
Rationale: Atrial fibrillation produces chaotic atrial activity and an irregularly irregular
ventricular response.
10. Atrial flutter commonly produces which characteristic ECG finding?
, A. Wide QRS complexes only
B. Sawtooth flutter waves
C. Completely absent electrical activity
D. One P wave for every QRS with a prolonged PR
Rationale: Atrial flutter commonly produces organized atrial activity appearing as repetitive
sawtooth flutter waves.
11. Which rhythm is immediately life-threatening and requires rapid
intervention?
A. Sinus bradycardia without symptoms
B. First-degree AV block
C. Ventricular fibrillation
D. Sinus arrhythmia
Rationale: Ventricular fibrillation produces ineffective ventricular activity and results in cardiac
arrest.
12. A patient is unresponsive, not breathing normally, and has no pulse. The
monitor shows ventricular fibrillation. What is the priority?
A. Obtain a 12-lead ECG
B. Give oral medication
C. Begin CPR and defibrillate as soon as possible
D. Wait for the rhythm to convert spontaneously
Rationale: VF is a shockable cardiac-arrest rhythm. High-quality CPR and prompt defibrillation
are critical.
13. Which rhythm is also considered a shockable cardiac-arrest rhythm?
A. Asystole
B. Pulseless electrical activity
C. Pulseless ventricular tachycardia
D. Sinus bradycardia
Rationale: Pulseless ventricular tachycardia, like ventricular fibrillation, is treated with
defibrillation and CPR.
14. A patient has a wide-complex tachycardia at 180 beats/min with no palpable
pulse. This should be treated as:
A. Sinus tachycardia
B. Pulseless ventricular tachycardia
