RELIAS DYSRHYTHMIA BASIC A – COMPLETE
WITH CORRECT ANSWERS AND DETAILED
RATIONALES .NO QUESTION ARE REPEATED
SECTION A: SINUS & ATRIAL RHYTHMS (Questions 1-50)
1. A 68-year-old male has a heart rate of 110 bpm. The ECG shows upright P waves
before every QRS, a PR interval of 0.16 seconds, and a QRS of 0.08 seconds. What
is the rhythm?
A) Normal Sinus Rhythm
B) Sinus Tachycardia
C) Sinus Bradycardia
D) Atrial Fibrillation
Correct Answer: B
Rationale: The rate exceeds 100 bpm, but all other criteria (P wave morphology,
PR interval, QRS duration) are normal. This defines Sinus Tachycardia, which is
often a physiologic response to stress, fever, or hypovolemia.
---
,2. Which ECG finding is diagnostic for Atrial Fibrillation?
A) Sawtooth flutter waves
B) Absent P waves and irregularly irregular ventricular response
C) Prolonged PR interval
D) Wide QRS complexes >0.12 seconds
Correct Answer: B
Rationale: Atrial Fibrillation is characterized by chaotic atrial depolarization with
no discernible P waves. The AV node conducts impulses irregularly, producing the
hallmark "irregularly irregular" rhythm. Sawtooth waves are seen in Atrial Flutter,
not fibrillation.
---
3. A patient presents with a heart rate of 48 bpm. The rhythm is regular, and there
is one P wave for every QRS. The PR interval is 0.18s and QRS is 0.10s. This is:
A) Sinus Arrhythmia
B) Sinus Bradycardia
C) Junctional Rhythm
D) First-degree AV block
Correct Answer: B
Rationale: Sinus Bradycardia is defined by a rate less than 60 bpm with normal P-
wave axis and conduction. The PR and QRS intervals are within normal limits. This
rhythm is often benign in athletes but symptomatic bradycardia requires
intervention.
,---
4. What is the most common cause of Sinus Tachycardia?
A) Increased intracranial pressure
B) Hypothermia
C) Pain, anxiety, or hypovolemia
D) Digitalis toxicity
Correct Answer: C
Rationale: Sinus tachycardia is a compensatory mechanism. Common causes
include physiologic stressors such as pain, anxiety, fever, dehydration, and heart
failure. It is rarely a primary arrhythmia and treatment focuses on the underlying
cause.
---
5. In Atrial Flutter, the atrial rate typically ranges between:
A) 40-60 bpm
B) 60-100 bpm
C) 150-250 bpm
D) 250-350 bpm
Correct Answer: D
Rationale: Atrial flutter is a macro-reentrant atrial tachycardia with an atrial rate of
250-350 bpm. The ventricular rate depends on the AV conduction ratio (e.g., 2:1,
, 4:1). The flutter waves appear as "sawtooth" or "F" waves, most prominent in
leads II, III, and aVF.
---
6. A 75-year-old female has an irregular rhythm with no P waves and a ventricular
rate of 90 bpm. What is the most appropriate initial treatment?
A) Synchronized cardioversion
B) Rate control with a beta-blocker or calcium channel blocker
C) Immediate defibrillation
D) Atropine 0.5 mg IV push
Correct Answer: B
Rationale: The rhythm is Atrial Fibrillation with a controlled ventricular rate. Rate
control is the initial strategy to prevent hemodynamic compromise and reduce
symptoms. Cardioversion is indicated if unstable or if rate control fails.
Defibrillation is only for pulseless VT/VF.
---
7. Which of the following is a classic ECG feature of Sinus Arrhythmia?
A) The heart rate varies with the respiratory cycle
B) A prolonged PR interval
C) Absence of P waves
D) A fixed, unchanging R-R interval
Correct Answer: A
WITH CORRECT ANSWERS AND DETAILED
RATIONALES .NO QUESTION ARE REPEATED
SECTION A: SINUS & ATRIAL RHYTHMS (Questions 1-50)
1. A 68-year-old male has a heart rate of 110 bpm. The ECG shows upright P waves
before every QRS, a PR interval of 0.16 seconds, and a QRS of 0.08 seconds. What
is the rhythm?
A) Normal Sinus Rhythm
B) Sinus Tachycardia
C) Sinus Bradycardia
D) Atrial Fibrillation
Correct Answer: B
Rationale: The rate exceeds 100 bpm, but all other criteria (P wave morphology,
PR interval, QRS duration) are normal. This defines Sinus Tachycardia, which is
often a physiologic response to stress, fever, or hypovolemia.
---
,2. Which ECG finding is diagnostic for Atrial Fibrillation?
A) Sawtooth flutter waves
B) Absent P waves and irregularly irregular ventricular response
C) Prolonged PR interval
D) Wide QRS complexes >0.12 seconds
Correct Answer: B
Rationale: Atrial Fibrillation is characterized by chaotic atrial depolarization with
no discernible P waves. The AV node conducts impulses irregularly, producing the
hallmark "irregularly irregular" rhythm. Sawtooth waves are seen in Atrial Flutter,
not fibrillation.
---
3. A patient presents with a heart rate of 48 bpm. The rhythm is regular, and there
is one P wave for every QRS. The PR interval is 0.18s and QRS is 0.10s. This is:
A) Sinus Arrhythmia
B) Sinus Bradycardia
C) Junctional Rhythm
D) First-degree AV block
Correct Answer: B
Rationale: Sinus Bradycardia is defined by a rate less than 60 bpm with normal P-
wave axis and conduction. The PR and QRS intervals are within normal limits. This
rhythm is often benign in athletes but symptomatic bradycardia requires
intervention.
,---
4. What is the most common cause of Sinus Tachycardia?
A) Increased intracranial pressure
B) Hypothermia
C) Pain, anxiety, or hypovolemia
D) Digitalis toxicity
Correct Answer: C
Rationale: Sinus tachycardia is a compensatory mechanism. Common causes
include physiologic stressors such as pain, anxiety, fever, dehydration, and heart
failure. It is rarely a primary arrhythmia and treatment focuses on the underlying
cause.
---
5. In Atrial Flutter, the atrial rate typically ranges between:
A) 40-60 bpm
B) 60-100 bpm
C) 150-250 bpm
D) 250-350 bpm
Correct Answer: D
Rationale: Atrial flutter is a macro-reentrant atrial tachycardia with an atrial rate of
250-350 bpm. The ventricular rate depends on the AV conduction ratio (e.g., 2:1,
, 4:1). The flutter waves appear as "sawtooth" or "F" waves, most prominent in
leads II, III, and aVF.
---
6. A 75-year-old female has an irregular rhythm with no P waves and a ventricular
rate of 90 bpm. What is the most appropriate initial treatment?
A) Synchronized cardioversion
B) Rate control with a beta-blocker or calcium channel blocker
C) Immediate defibrillation
D) Atropine 0.5 mg IV push
Correct Answer: B
Rationale: The rhythm is Atrial Fibrillation with a controlled ventricular rate. Rate
control is the initial strategy to prevent hemodynamic compromise and reduce
symptoms. Cardioversion is indicated if unstable or if rate control fails.
Defibrillation is only for pulseless VT/VF.
---
7. Which of the following is a classic ECG feature of Sinus Arrhythmia?
A) The heart rate varies with the respiratory cycle
B) A prolonged PR interval
C) Absence of P waves
D) A fixed, unchanging R-R interval
Correct Answer: A
