Relias Dysrhythmia Basic Test ECG Rhythm
Interpretation 2026/2027 – Questions and
Answers | Complete Verified Answers |
Detailed Rationales – Pass Guaranteed –
A+ Graded
1. A patient's cardiac monitor shows a regular rhythm with a rate of 45
bpm. The P waves are present and upright before each QRS complex,
and the PR interval is 0.16 seconds. The QRS complex is narrow (0.08
seconds). What is the correct interpretation of this rhythm?
A) Normal Sinus Rhythm
B) Sinus Bradycardia
C) Sinus Bradycardia
D) Junctional Rhythm
Rationale: The rhythm is regular, the rate is less than 60 bpm (45 bpm), and
there is a normal P wave before every QRS complex with a normal PR
interval. These are the defining characteristics of Sinus Bradycardia. Normal
Sinus Rhythm would have a rate of 60-100 bpm. A Junctional Rhythm would
typically have an absent or inverted P wave.
2. A nurse observes a rhythm on the ECG monitor that is chaotic, with
no discernible P waves, an irregular ventricular response, and a
fibrillatory baseline. The rate is rapid and grossly irregular. What is the
priority nursing action?
,A) Administer Adenosine 6 mg IV push
B) Prepare for synchronized cardioversion
C) Assess the patient's level of consciousness and vital signs
D) Document the rhythm and continue to monitor
Rationale: The rhythm described is Atrial Fibrillation. The priority action for
any new arrhythmia is to assess the patient's hemodynamic status (level of
consciousness, vital signs, chest pain, shortness of breath). If the patient is
unstable, immediate intervention (e.g., cardioversion) is required. If stable, the
focus shifts to rate control and anticoagulation. Adenosine is used for SVT,
not Afib.
3. Which of the following rhythms is characterized by a progressive
lengthening of the PR interval until a QRS complex is dropped?
A) First-Degree AV Block
B) Second-Degree AV Block, Type I (Mobitz I / Wenckebach)
C) Second-Degree AV Block, Type II (Mobitz II)
D) Third-Degree AV Block
Rationale: Second-Degree AV Block, Type I (Wenckebach) is defined by the
progressive lengthening of the PR interval with each beat until a QRS
complex is dropped. First-Degree AV Block has a consistently prolonged PR
interval (>0.20 sec) with no dropped beats. Mobitz II has a constant PR
interval with sudden dropped beats. Third-Degree AV Block has no
relationship between P waves and QRS complexes.
4. A patient is in Ventricular Tachycardia (VT) with a pulse. The patient
is symptomatic with chest pain and a blood pressure of 80/50 mmHg.
What is the most appropriate immediate intervention?
A) Defibrillation
B) Synchronized Cardioversion
,C) Amiodarone 150 mg IV bolus
D) CPR and defibrillation
Rationale: For a patient with symptomatic Ventricular Tachycardia with a
pulse, the treatment of choice is Synchronized Cardioversion. Defibrillation is
used for pulseless VT or Ventricular Fibrillation. Amiodarone may be used for
stable VT or as an adjunct, but for an unstable patient with a pulse,
cardioversion is the priority. CPR is initiated for a pulseless patient.
5. What is the hallmark ECG characteristic of Ventricular Fibrillation
(VFib)?
A) A sawtooth pattern with a rate of 250-350 bpm
B) Chaotic, irregular, and undulating waves with no discernible QRS
complexes
C) A regular, wide-complex tachycardia at a rate of 150 bpm
D) A flatline with no electrical activity
Rationale: Ventricular Fibrillation is characterized by chaotic, irregular
electrical activity with no identifiable P waves, QRS complexes, or T waves. It
is a lethal rhythm that requires immediate defibrillation. A sawtooth pattern
describes Atrial Flutter. A regular, wide-complex tachycardia describes
Ventricular Tachycardia. A flatline describes Asystole.
6. A patient's ECG shows a regular rhythm with a rate of 180 bpm. The
QRS complexes are narrow (0.08 sec). P waves are not clearly visible.
The patient is stable but feels palpitations. What is the most likely
rhythm?
A) Ventricular Tachycardia
B) Atrial Fibrillation
C) Supraventricular Tachycardia (SVT)
D) Sinus Tachycardia
, Rationale: The rhythm described is Supraventricular Tachycardia (SVT). Key
features include a regular, narrow-complex tachycardia with a rate typically
>150 bpm and hidden or absent P waves. Ventricular Tachycardia would
have wide QRS complexes. Atrial Fibrillation is irregular. Sinus Tachycardia
would have visible P waves and a rate typically <150 bpm.
7. Which of the following is a characteristic of a Third-Degree
(Complete) Heart Block?
A) A progressive lengthening of the PR interval
B) A constant PR interval with dropped QRS complexes
C) Complete dissociation between P waves and QRS complexes
D) A prolonged PR interval >0.20 seconds
Rationale: Third-Degree AV Block (Complete Heart Block) is characterized by
a complete absence of conduction between the atria and ventricles. The P
waves and QRS complexes are completely dissociated, meaning they have no
relationship to each other. The atrial rate is typically faster than the
ventricular rate. Options A, B, and D describe other types of AV blocks.
8. A patient with a history of heart failure is on a telemetry unit. The
monitor shows a rhythm with a rate of 120 bpm, a sawtooth pattern of
P waves, and a regular ventricular response. What is the correct
interpretation?
A) Atrial Fibrillation
B) Atrial Flutter
C) Sinus Tachycardia
D) Ventricular Tachycardia
Rationale: Atrial Flutter is characterized by a sawtooth pattern of atrial waves
(F waves), often at a rate of 250-350 bpm. The ventricular response can be
regular or irregular depending on the conduction ratio (e.g., 2:1, 3:1). Atrial
Interpretation 2026/2027 – Questions and
Answers | Complete Verified Answers |
Detailed Rationales – Pass Guaranteed –
A+ Graded
1. A patient's cardiac monitor shows a regular rhythm with a rate of 45
bpm. The P waves are present and upright before each QRS complex,
and the PR interval is 0.16 seconds. The QRS complex is narrow (0.08
seconds). What is the correct interpretation of this rhythm?
A) Normal Sinus Rhythm
B) Sinus Bradycardia
C) Sinus Bradycardia
D) Junctional Rhythm
Rationale: The rhythm is regular, the rate is less than 60 bpm (45 bpm), and
there is a normal P wave before every QRS complex with a normal PR
interval. These are the defining characteristics of Sinus Bradycardia. Normal
Sinus Rhythm would have a rate of 60-100 bpm. A Junctional Rhythm would
typically have an absent or inverted P wave.
2. A nurse observes a rhythm on the ECG monitor that is chaotic, with
no discernible P waves, an irregular ventricular response, and a
fibrillatory baseline. The rate is rapid and grossly irregular. What is the
priority nursing action?
,A) Administer Adenosine 6 mg IV push
B) Prepare for synchronized cardioversion
C) Assess the patient's level of consciousness and vital signs
D) Document the rhythm and continue to monitor
Rationale: The rhythm described is Atrial Fibrillation. The priority action for
any new arrhythmia is to assess the patient's hemodynamic status (level of
consciousness, vital signs, chest pain, shortness of breath). If the patient is
unstable, immediate intervention (e.g., cardioversion) is required. If stable, the
focus shifts to rate control and anticoagulation. Adenosine is used for SVT,
not Afib.
3. Which of the following rhythms is characterized by a progressive
lengthening of the PR interval until a QRS complex is dropped?
A) First-Degree AV Block
B) Second-Degree AV Block, Type I (Mobitz I / Wenckebach)
C) Second-Degree AV Block, Type II (Mobitz II)
D) Third-Degree AV Block
Rationale: Second-Degree AV Block, Type I (Wenckebach) is defined by the
progressive lengthening of the PR interval with each beat until a QRS
complex is dropped. First-Degree AV Block has a consistently prolonged PR
interval (>0.20 sec) with no dropped beats. Mobitz II has a constant PR
interval with sudden dropped beats. Third-Degree AV Block has no
relationship between P waves and QRS complexes.
4. A patient is in Ventricular Tachycardia (VT) with a pulse. The patient
is symptomatic with chest pain and a blood pressure of 80/50 mmHg.
What is the most appropriate immediate intervention?
A) Defibrillation
B) Synchronized Cardioversion
,C) Amiodarone 150 mg IV bolus
D) CPR and defibrillation
Rationale: For a patient with symptomatic Ventricular Tachycardia with a
pulse, the treatment of choice is Synchronized Cardioversion. Defibrillation is
used for pulseless VT or Ventricular Fibrillation. Amiodarone may be used for
stable VT or as an adjunct, but for an unstable patient with a pulse,
cardioversion is the priority. CPR is initiated for a pulseless patient.
5. What is the hallmark ECG characteristic of Ventricular Fibrillation
(VFib)?
A) A sawtooth pattern with a rate of 250-350 bpm
B) Chaotic, irregular, and undulating waves with no discernible QRS
complexes
C) A regular, wide-complex tachycardia at a rate of 150 bpm
D) A flatline with no electrical activity
Rationale: Ventricular Fibrillation is characterized by chaotic, irregular
electrical activity with no identifiable P waves, QRS complexes, or T waves. It
is a lethal rhythm that requires immediate defibrillation. A sawtooth pattern
describes Atrial Flutter. A regular, wide-complex tachycardia describes
Ventricular Tachycardia. A flatline describes Asystole.
6. A patient's ECG shows a regular rhythm with a rate of 180 bpm. The
QRS complexes are narrow (0.08 sec). P waves are not clearly visible.
The patient is stable but feels palpitations. What is the most likely
rhythm?
A) Ventricular Tachycardia
B) Atrial Fibrillation
C) Supraventricular Tachycardia (SVT)
D) Sinus Tachycardia
, Rationale: The rhythm described is Supraventricular Tachycardia (SVT). Key
features include a regular, narrow-complex tachycardia with a rate typically
>150 bpm and hidden or absent P waves. Ventricular Tachycardia would
have wide QRS complexes. Atrial Fibrillation is irregular. Sinus Tachycardia
would have visible P waves and a rate typically <150 bpm.
7. Which of the following is a characteristic of a Third-Degree
(Complete) Heart Block?
A) A progressive lengthening of the PR interval
B) A constant PR interval with dropped QRS complexes
C) Complete dissociation between P waves and QRS complexes
D) A prolonged PR interval >0.20 seconds
Rationale: Third-Degree AV Block (Complete Heart Block) is characterized by
a complete absence of conduction between the atria and ventricles. The P
waves and QRS complexes are completely dissociated, meaning they have no
relationship to each other. The atrial rate is typically faster than the
ventricular rate. Options A, B, and D describe other types of AV blocks.
8. A patient with a history of heart failure is on a telemetry unit. The
monitor shows a rhythm with a rate of 120 bpm, a sawtooth pattern of
P waves, and a regular ventricular response. What is the correct
interpretation?
A) Atrial Fibrillation
B) Atrial Flutter
C) Sinus Tachycardia
D) Ventricular Tachycardia
Rationale: Atrial Flutter is characterized by a sawtooth pattern of atrial waves
(F waves), often at a rate of 250-350 bpm. The ventricular response can be
regular or irregular depending on the conduction ratio (e.g., 2:1, 3:1). Atrial
