ACLS POST TEST EXAM 2 NEWEST VERSION 2026-2027
ACTUAL 52 QUESTION AND CORRECT DETAILED
ANSWERS RATED A GRADE.
QUESTION
Which best describes this rhythm?
A. Third-degree atrioventricular block
B. Second-degree AV block type I
C. Second-degree AV block type II
D. Monomorphic ventricular tachycardia
Correct Answer: A
Expert Rationale
A third-degree atrioventricular (AV) block is characterized by complete
dissociation between atrial and ventricular activity, with no conducted P
waves reaching the ventricles. The atria and ventricles beat
independently, with atrial rate typically faster than ventricular rate. The
P waves bear no relationship to the QRS complexes. This rhythm results
from complete interruption of conduction between the atria and
ventricles, often at the AV node or bundle of His. Patients with third-
degree AV block are at high risk for hemodynamic instability and may
require transcutaneous or transvenous pacing. This rhythm is a
significant finding in the ACLS setting because it often causes severe
bradycardia and can lead to cardiac arrest. The treatment focuses on
maintaining adequate heart rate and perfusion while addressing the
underlying cause.
,DIF: Cognitive Level: Understand (Comprehension)
TOP: ACLS - Cardiac Rhythm Interpretation
MSC: Cardiovascular Emergencies
QUESTION
Which type of atrioventricular (AV) block best describes this rhythm?
A. First-degree AV block
B. Second-degree AV block type I
C. Second-degree AV block type II
D. Third-degree AV block
Correct Answer: C
Expert Rationale
Second-degree AV block type II (Mobitz II) is characterized by
intermittent non-conducted P waves with a constant PR interval on
conducted beats. Unlike Type I (Wenckebach), there is no progressive
prolongation of the PR interval before the dropped beat. The PR
intervals of conducted beats are constant and may be normal or
prolonged. Type II block is typically located at the bundle of His or
bundle branches and carries a higher risk of progression to complete
heart block and cardiac arrest. This rhythm is more dangerous than
Type I block and often requires pacing. Patients with Type II AV block
are at significant risk for sudden hemodynamic deterioration and should
be closely monitored with immediate availability of transcutaneous
pacing.
,DIF: Cognitive Level: Understand (Comprehension)
TOP: ACLS - Cardiac Rhythm Interpretation
MSC: Cardiovascular Emergencies
QUESTION
Which best describes this rhythm?
A. Atrial fibrillation
B. Ventricular tachycardia
C. Monomorphic ventricular tachycardia
D. Polymorphic ventricular tachycardia
Correct Answer: C
Expert Rationale
Monomorphic ventricular tachycardia (VT) is a wide-complex
tachycardia characterized by QRS complexes that are uniform in shape,
amplitude, and duration. The rhythm typically originates from a single
focus within the ventricular myocardium and has a rate greater than
100 beats per minute (usually 150-200 beats/min). Monomorphic VT
can be sustained or nonsustained and may or may not be associated
with a palpable pulse. In the ACLS algorithm, pulseless VT is treated as a
shockable rhythm requiring immediate defibrillation, while stable VT
with a pulse may be treated with antiarrhythmic medications.
Polymorphic VT (Torsades de Pointes) would show variation in QRS
morphology and axis. Monomorphic VT is a common dysrhythmia in
patients with structural heart disease, especially those with prior
myocardial infarction or cardiomyopathy.
, DIF: Cognitive Level: Understand (Comprehension)
TOP: ACLS - Cardiac Rhythm Interpretation
MSC: Cardiovascular Emergencies
QUESTION
A patient in respiratory distress and with a blood pressure of 70/50
mmHg presents with the lead II ECG rhythm shown here. Which is the
appropriate treatment?
A. Administration of adenosine
B. Performing synchronized cardioversion
C. Performing defibrillation
D. Administration of atropine
Correct Answer: B
Expert Rationale
The patient described has unstable supraventricular tachycardia (SVT)
with evidence of hemodynamic compromise (hypotension, respiratory
distress). Synchronized cardioversion (Option B) is the appropriate
treatment for unstable tachyarrhythmias with a pulse. The synchronized
mode ensures that the shock is delivered at the peak of the R wave to
avoid delivering the shock during the vulnerable period of the cardiac
cycle, which could cause ventricular fibrillation. Adenosine (Option A) is
appropriate for stable SVT but is not recommended in unstable patients
because it may cause transient worsening of the rhythm. Defibrillation
(Option C) is used for pulseless rhythms such as ventricular fibrillation
or pulseless ventricular tachycardia. Atropine (Option D) is used for
symptomatic bradycardia, not tachycardia. In unstable patients with
ACTUAL 52 QUESTION AND CORRECT DETAILED
ANSWERS RATED A GRADE.
QUESTION
Which best describes this rhythm?
A. Third-degree atrioventricular block
B. Second-degree AV block type I
C. Second-degree AV block type II
D. Monomorphic ventricular tachycardia
Correct Answer: A
Expert Rationale
A third-degree atrioventricular (AV) block is characterized by complete
dissociation between atrial and ventricular activity, with no conducted P
waves reaching the ventricles. The atria and ventricles beat
independently, with atrial rate typically faster than ventricular rate. The
P waves bear no relationship to the QRS complexes. This rhythm results
from complete interruption of conduction between the atria and
ventricles, often at the AV node or bundle of His. Patients with third-
degree AV block are at high risk for hemodynamic instability and may
require transcutaneous or transvenous pacing. This rhythm is a
significant finding in the ACLS setting because it often causes severe
bradycardia and can lead to cardiac arrest. The treatment focuses on
maintaining adequate heart rate and perfusion while addressing the
underlying cause.
,DIF: Cognitive Level: Understand (Comprehension)
TOP: ACLS - Cardiac Rhythm Interpretation
MSC: Cardiovascular Emergencies
QUESTION
Which type of atrioventricular (AV) block best describes this rhythm?
A. First-degree AV block
B. Second-degree AV block type I
C. Second-degree AV block type II
D. Third-degree AV block
Correct Answer: C
Expert Rationale
Second-degree AV block type II (Mobitz II) is characterized by
intermittent non-conducted P waves with a constant PR interval on
conducted beats. Unlike Type I (Wenckebach), there is no progressive
prolongation of the PR interval before the dropped beat. The PR
intervals of conducted beats are constant and may be normal or
prolonged. Type II block is typically located at the bundle of His or
bundle branches and carries a higher risk of progression to complete
heart block and cardiac arrest. This rhythm is more dangerous than
Type I block and often requires pacing. Patients with Type II AV block
are at significant risk for sudden hemodynamic deterioration and should
be closely monitored with immediate availability of transcutaneous
pacing.
,DIF: Cognitive Level: Understand (Comprehension)
TOP: ACLS - Cardiac Rhythm Interpretation
MSC: Cardiovascular Emergencies
QUESTION
Which best describes this rhythm?
A. Atrial fibrillation
B. Ventricular tachycardia
C. Monomorphic ventricular tachycardia
D. Polymorphic ventricular tachycardia
Correct Answer: C
Expert Rationale
Monomorphic ventricular tachycardia (VT) is a wide-complex
tachycardia characterized by QRS complexes that are uniform in shape,
amplitude, and duration. The rhythm typically originates from a single
focus within the ventricular myocardium and has a rate greater than
100 beats per minute (usually 150-200 beats/min). Monomorphic VT
can be sustained or nonsustained and may or may not be associated
with a palpable pulse. In the ACLS algorithm, pulseless VT is treated as a
shockable rhythm requiring immediate defibrillation, while stable VT
with a pulse may be treated with antiarrhythmic medications.
Polymorphic VT (Torsades de Pointes) would show variation in QRS
morphology and axis. Monomorphic VT is a common dysrhythmia in
patients with structural heart disease, especially those with prior
myocardial infarction or cardiomyopathy.
, DIF: Cognitive Level: Understand (Comprehension)
TOP: ACLS - Cardiac Rhythm Interpretation
MSC: Cardiovascular Emergencies
QUESTION
A patient in respiratory distress and with a blood pressure of 70/50
mmHg presents with the lead II ECG rhythm shown here. Which is the
appropriate treatment?
A. Administration of adenosine
B. Performing synchronized cardioversion
C. Performing defibrillation
D. Administration of atropine
Correct Answer: B
Expert Rationale
The patient described has unstable supraventricular tachycardia (SVT)
with evidence of hemodynamic compromise (hypotension, respiratory
distress). Synchronized cardioversion (Option B) is the appropriate
treatment for unstable tachyarrhythmias with a pulse. The synchronized
mode ensures that the shock is delivered at the peak of the R wave to
avoid delivering the shock during the vulnerable period of the cardiac
cycle, which could cause ventricular fibrillation. Adenosine (Option A) is
appropriate for stable SVT but is not recommended in unstable patients
because it may cause transient worsening of the rhythm. Defibrillation
(Option C) is used for pulseless rhythms such as ventricular fibrillation
or pulseless ventricular tachycardia. Atropine (Option D) is used for
symptomatic bradycardia, not tachycardia. In unstable patients with
