Relias Advanced Dysrhythmia Exam A 2025
[85 Real Questions] 100% Correct Verified
Answers | Newest Version
Question 1: The rhythm strip shows a regular ventricular rate of 180 bpm, narrow QRS complexes,
and no discernible P waves. The most likely rhythm is:
A) Atrial flutter
B) Sinus tachycardia
C) Paroxysmal supraventricular tachycardia (PSVT)
D) Ventricular tachycardia
Correct Answer: C) Paroxysmal supraventricular tachycardia (PSVT)
Explanation: PSVT classically presents with sudden-onset narrow-complex tachycardia at 150–250
bpm; P waves are often hidden within or immediately after the QRS.
Question 2: Which ECG finding is the hallmark of second-degree AV block Type II?
A) Progressive PR lengthening then a dropped QRS
B) Constant PR with intermittent non-conducted P waves
C) PR shortening after a pause
D) 1:1 AV conduction at 120 bpm
Correct Answer: B) Constant PR with intermittent non-conducted P waves
Explanation: Mobitz II is a high-risk block where the PR interval does not lengthen; instead, atrial
impulses suddenly fail to conduct, often heralding complete heart block.
Question 3: A wide-complex tachycardia at 200 bpm shows extreme axis deviation and AV
dissociation. The rhythm is:
A) Atrial fibrillation with aberrancy
B) PSVT with bundle-branch block
C) Ventricular tachycardia
,D) Sinus tachycardia with PVCs
Correct Answer: C) Ventricular tachycardia
Explanation: Wide QRS > 120 ms, rate > 100 bpm, AV dissociation, and extreme axis are all VT
criteria; treat as VT until proven otherwise.
Question 4: The rhythm strip shows saw-tooth flutter waves at 300 bpm with 2:1 conduction. The
ventricular rate is:
A) 150 bpm
B) 300 bpm
C) 100 bpm
D) 250 bpm
Correct Answer: A) 150 bpm
Explanation: Classic atrial flutter has an atrial rate of ~300 bpm; 2:1 conduction yields a ventricular
rate of exactly half, 150 bpm.
Question 5: Which intervention is first-line for unstable polymorphic VT with a pulse?
A) Adenosine 12 mg IV push
B) Immediate synchronized cardioversion
C) Amiodarone 150 mg IV over 10 min
D) Vagal maneuvers
Correct Answer: B) Immediate synchronized cardioversion
Explanation: Unstable polymorphic (irregular) VT is treated like VF: immediate unsynchronized (or
synchronized if clearly identifiable R waves) cardioversion at 200 J.
Question 6: ECG shows regular P waves at 70 bpm, constant PR, but every third QRS is dropped.
This is:
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) Second-degree AV block Type II
Explanation: Constant PR with intermittent dropped beats (e.g., 3:2 conduction) without PR
prolongation defines Mobitz II, a high-risk rhythm.
Question 7: Which ECG feature distinguishes accelerated idioventricular rhythm (AIVR) from VT?
A) Rate 110–150 bpm
B) Rate 50–100 bpm
C) P waves precede every QRS
D) QRS width < 100 ms
Correct Answer: B) Rate 50–100 bpm
Explanation: AIVR is a “slow” ventricular rhythm (50–100 bpm) often seen reperfusing MI; VT is ≥
100 bpm and usually faster.
Question 8: A patient in atrial fibrillation is started on dofetilide. Which lab must be checked before
the first dose?
A) Serum potassium
B) INR
C) Troponin
D) BNP
Correct Answer: A) Serum potassium
Explanation: Hypokalemia increases risk of torsades with dofetilide; K⁺ should be ≥ 4.0 mEq/L and
Mg²⁺ ≥ 2.0 mg/dL.
Question 9: Which antiarrhythmic class prolongs repolarization by blocking potassium channels?
A) Class I
B) Class II
C) Class III
D) Class IV
Correct Answer: C) Class III
, Explanation: Class III drugs (amiodarone, sotalol, dofetilide) block IKr channels, prolonging phase 3
repolarization and QT interval.
Question 10: The rhythm strip shows irregularly irregular narrow QRS at 130 bpm with no P waves.
The rhythm is:
A) Atrial flutter
B) Sinus tachycardia
C) Atrial fibrillation
D) PSVT
Correct Answer: C) Atrial fibrillation
Explanation: Irregularly irregular narrow-complex tachycardia without discernible P waves is
pathognomonic for atrial fibrillation.
Question 11: Which vagal maneuver is safest and most effective for terminating PSVT?
A) Carotid sinus massage (both sides simultaneously)
B) Cold water facial immersion
C) Modified Valsalva (strained 40 mmHg for 15 s, supine, then leg lift)
D) Coughing vigorously
Correct Answer: C) Modified Valsalva (strained 40 mmHg for 15 s, supine, then leg lift)
Explanation: The modified Valsalva doubles success rate over standard by augmenting venous
return and increasing baroreceptor firing.
Question 12: Which ECG finding is expected in hyperkalemia before the QRS widens?
A) Peaked T waves
B) U waves
C) Delta waves
D) Osborne waves
Correct Answer: A) Peaked T waves
Explanation: Tent-shaped T waves with narrow base are the earliest sign of hyperkalemia, often at
K⁺ ≥ 5.5 mEq/L.
[85 Real Questions] 100% Correct Verified
Answers | Newest Version
Question 1: The rhythm strip shows a regular ventricular rate of 180 bpm, narrow QRS complexes,
and no discernible P waves. The most likely rhythm is:
A) Atrial flutter
B) Sinus tachycardia
C) Paroxysmal supraventricular tachycardia (PSVT)
D) Ventricular tachycardia
Correct Answer: C) Paroxysmal supraventricular tachycardia (PSVT)
Explanation: PSVT classically presents with sudden-onset narrow-complex tachycardia at 150–250
bpm; P waves are often hidden within or immediately after the QRS.
Question 2: Which ECG finding is the hallmark of second-degree AV block Type II?
A) Progressive PR lengthening then a dropped QRS
B) Constant PR with intermittent non-conducted P waves
C) PR shortening after a pause
D) 1:1 AV conduction at 120 bpm
Correct Answer: B) Constant PR with intermittent non-conducted P waves
Explanation: Mobitz II is a high-risk block where the PR interval does not lengthen; instead, atrial
impulses suddenly fail to conduct, often heralding complete heart block.
Question 3: A wide-complex tachycardia at 200 bpm shows extreme axis deviation and AV
dissociation. The rhythm is:
A) Atrial fibrillation with aberrancy
B) PSVT with bundle-branch block
C) Ventricular tachycardia
,D) Sinus tachycardia with PVCs
Correct Answer: C) Ventricular tachycardia
Explanation: Wide QRS > 120 ms, rate > 100 bpm, AV dissociation, and extreme axis are all VT
criteria; treat as VT until proven otherwise.
Question 4: The rhythm strip shows saw-tooth flutter waves at 300 bpm with 2:1 conduction. The
ventricular rate is:
A) 150 bpm
B) 300 bpm
C) 100 bpm
D) 250 bpm
Correct Answer: A) 150 bpm
Explanation: Classic atrial flutter has an atrial rate of ~300 bpm; 2:1 conduction yields a ventricular
rate of exactly half, 150 bpm.
Question 5: Which intervention is first-line for unstable polymorphic VT with a pulse?
A) Adenosine 12 mg IV push
B) Immediate synchronized cardioversion
C) Amiodarone 150 mg IV over 10 min
D) Vagal maneuvers
Correct Answer: B) Immediate synchronized cardioversion
Explanation: Unstable polymorphic (irregular) VT is treated like VF: immediate unsynchronized (or
synchronized if clearly identifiable R waves) cardioversion at 200 J.
Question 6: ECG shows regular P waves at 70 bpm, constant PR, but every third QRS is dropped.
This is:
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) Second-degree AV block Type II
Explanation: Constant PR with intermittent dropped beats (e.g., 3:2 conduction) without PR
prolongation defines Mobitz II, a high-risk rhythm.
Question 7: Which ECG feature distinguishes accelerated idioventricular rhythm (AIVR) from VT?
A) Rate 110–150 bpm
B) Rate 50–100 bpm
C) P waves precede every QRS
D) QRS width < 100 ms
Correct Answer: B) Rate 50–100 bpm
Explanation: AIVR is a “slow” ventricular rhythm (50–100 bpm) often seen reperfusing MI; VT is ≥
100 bpm and usually faster.
Question 8: A patient in atrial fibrillation is started on dofetilide. Which lab must be checked before
the first dose?
A) Serum potassium
B) INR
C) Troponin
D) BNP
Correct Answer: A) Serum potassium
Explanation: Hypokalemia increases risk of torsades with dofetilide; K⁺ should be ≥ 4.0 mEq/L and
Mg²⁺ ≥ 2.0 mg/dL.
Question 9: Which antiarrhythmic class prolongs repolarization by blocking potassium channels?
A) Class I
B) Class II
C) Class III
D) Class IV
Correct Answer: C) Class III
, Explanation: Class III drugs (amiodarone, sotalol, dofetilide) block IKr channels, prolonging phase 3
repolarization and QT interval.
Question 10: The rhythm strip shows irregularly irregular narrow QRS at 130 bpm with no P waves.
The rhythm is:
A) Atrial flutter
B) Sinus tachycardia
C) Atrial fibrillation
D) PSVT
Correct Answer: C) Atrial fibrillation
Explanation: Irregularly irregular narrow-complex tachycardia without discernible P waves is
pathognomonic for atrial fibrillation.
Question 11: Which vagal maneuver is safest and most effective for terminating PSVT?
A) Carotid sinus massage (both sides simultaneously)
B) Cold water facial immersion
C) Modified Valsalva (strained 40 mmHg for 15 s, supine, then leg lift)
D) Coughing vigorously
Correct Answer: C) Modified Valsalva (strained 40 mmHg for 15 s, supine, then leg lift)
Explanation: The modified Valsalva doubles success rate over standard by augmenting venous
return and increasing baroreceptor firing.
Question 12: Which ECG finding is expected in hyperkalemia before the QRS widens?
A) Peaked T waves
B) U waves
C) Delta waves
D) Osborne waves
Correct Answer: A) Peaked T waves
Explanation: Tent-shaped T waves with narrow base are the earliest sign of hyperkalemia, often at
K⁺ ≥ 5.5 mEq/L.
