RELIAS DYSRHYTHMIA BASIC A EXAM 2026/2027 |
Elaboration Questions & Answers | Graded A+ | 100%
Correct | Pass Guaranteed - A+ Graded
[Section 1: Normal Sinus Rhythm & Sinus Node Dysrhythmias
(Questions 1-15)]
Question 1
A patient has an ECG showing a heart rate of 72 bpm, regular rhythm, upright P waves in
lead II preceding each QRS complex, PR interval of 0.16 seconds, and QRS duration of
0.08 seconds. Which rhythm is present?
A. Sinus bradycardia
B. Normal sinus rhythm [CORRECT]
C. Sinus tachycardia
D. First-degree AV block
Rationale: Normal sinus rhythm requires rate 60-100 bpm, regular rhythm, upright P
wave in lead II before each QRS, PR interval 0.12-0.20 seconds (3-5 small boxes), and
QRS duration <0.12 seconds. All criteria are met: rate 72 bpm, regular, upright P waves,
PR 0.16 sec, QRS 0.08 sec. Sinus bradycardia (Option A) requires rate <60 bpm. Sinus
tachycardia (Option C) requires rate >100 bpm. First-degree AV block (Option D)
requires PR >0.20 seconds. This is the foundational rhythm against which all
dysrhythmias are compared.
Correct Answer: B
,Question 2
A 28-year-old marathon runner has a resting heart rate of 48 bpm on ECG. The rhythm is
regular with normal P waves, PR interval 0.14 seconds, and narrow QRS complexes. He
is asymptomatic. Which diagnosis and management are most appropriate?
A. Sinus tachycardia; no treatment needed
B. Sinus bradycardia; no treatment needed [CORRECT]
C. Sinus bradycardia; atropine 0.5 mg IV immediately
D. Third-degree AV block; pacemaker insertion
Rationale: Sinus bradycardia is defined as NSR with rate <60 bpm. In trained athletes,
physiologic sinus bradycardia is common due to increased vagal tone and requires no
treatment if asymptomatic. Atropine (Option C) is indicated only for symptomatic
bradycardia (hypotension, syncope, chest pain, dyspnea, AMS). Third-degree AV block
(Option D) would show AV dissociation with no relationship between P waves and QRS
complexes. The asymptomatic status and athletic conditioning guide expectant
management.
Correct Answer: B
Question 3
A patient on metoprolol presents with fatigue, dizziness, and a heart rate of 52 bpm. BP
is 88/52 mmHg. The ECG shows regular rhythm with upright P waves, PR 0.18 seconds,
and narrow QRS. Which is the FIRST-line treatment?
A. Transcutaneous pacing immediately
B. Atropine 0.5 mg IV [CORRECT]
C. Epinephrine 1 mg IV push
D. Amiodarone 300 mg IV
,Rationale: Symptomatic sinus bradycardia (hypotension, fatigue, dizziness) requires
treatment per ACLS guidelines. First-line is atropine 0.5 mg IV every 3-5 minutes
(maximum 3 mg). Transcutaneous pacing (Option A) is reserved for atropine-refractory
or unstable patients. Epinephrine infusion 2-10 mcg/min (Option C) is second-line if
atropine fails. Amiodarone (Option D) is contraindicated as it would further slow the
heart rate. The beta-blocker effect from metoprolol contributes to the bradycardia.
Correct Answer: B
Question 4
A patient with inferior MI (RCA occlusion) develops sinus bradycardia at 46 bpm with
hypotension (SBP 78 mmHg) and altered mental status. Atropine 3 mg has been given
without effect. What is the next appropriate intervention?
A. Give additional atropine 1 mg IV
B. Initiate transcutaneous pacing [CORRECT]
C. Administer adenosine 6 mg rapid IV push
D. Perform synchronized cardioversion at 50J
Rationale: After maximum atropine dosing (3 mg), symptomatic bradycardia requires
transcutaneous pacing if the patient remains unstable. Inferior MI commonly affects the
RCA, which supplies the SA and AV nodes, causing bradycardia. Additional atropine
(Option A) exceeds the maximum dose. Adenosine (Option C) would worsen
bradycardia and is contraindicated. Synchronized cardioversion (Option D) is for
tachyarrhythmias, not bradycardia. Dopamine 2-10 mcg/kg/min or epinephrine 2-10
mcg/min infusion are alternatives while preparing pacing.
Correct Answer: B
, Question 5
A patient has a heart rate of 140 bpm with regular rhythm, upright P waves in lead II
preceding each QRS, PR interval 0.14 seconds, and narrow QRS complexes. The patient
has a fever of 39°C and is septic. Which diagnosis and treatment are most appropriate?
A. Atrial fibrillation; anticoagulation and rate control
B. Sinus tachycardia; treat underlying sepsis and fever [CORRECT]
C. Supraventricular tachycardia; adenosine 6 mg IV push
D. Ventricular tachycardia; amiodarone 150 mg IV
Rationale: Sinus tachycardia is NSR with rate >100 bpm, typically 100-160 bpm. Fever
increases heart rate approximately 10 bpm per 1°C; 39°C explains the elevated rate.
Treatment targets the underlying cause (sepsis, fever, hypovolemia) rather than the rate.
Atrial fibrillation (Option A) would be irregularly irregular without distinct P waves. SVT
(Option C) would typically have rate >150 bpm with P waves often not visible. VT
(Option D) would show wide QRS complexes. Sinus tachycardia is a compensatory
response, not a primary rhythm disturbance.
Correct Answer: B
Question 6
A patient with anxiety and caffeine overuse presents with palpitations. ECG shows rate
118 bpm, regular rhythm, upright P waves, PR 0.15 seconds, narrow QRS. BP is 132/84
mmHg. The patient is otherwise asymptomatic. Which management is most
appropriate?
A. Immediate synchronized cardioversion
B. Metoprolol 5 mg IV to slow rate
C. Reassurance and avoidance of triggers [CORRECT]
D. Adenosine 6 mg rapid IV push
Elaboration Questions & Answers | Graded A+ | 100%
Correct | Pass Guaranteed - A+ Graded
[Section 1: Normal Sinus Rhythm & Sinus Node Dysrhythmias
(Questions 1-15)]
Question 1
A patient has an ECG showing a heart rate of 72 bpm, regular rhythm, upright P waves in
lead II preceding each QRS complex, PR interval of 0.16 seconds, and QRS duration of
0.08 seconds. Which rhythm is present?
A. Sinus bradycardia
B. Normal sinus rhythm [CORRECT]
C. Sinus tachycardia
D. First-degree AV block
Rationale: Normal sinus rhythm requires rate 60-100 bpm, regular rhythm, upright P
wave in lead II before each QRS, PR interval 0.12-0.20 seconds (3-5 small boxes), and
QRS duration <0.12 seconds. All criteria are met: rate 72 bpm, regular, upright P waves,
PR 0.16 sec, QRS 0.08 sec. Sinus bradycardia (Option A) requires rate <60 bpm. Sinus
tachycardia (Option C) requires rate >100 bpm. First-degree AV block (Option D)
requires PR >0.20 seconds. This is the foundational rhythm against which all
dysrhythmias are compared.
Correct Answer: B
,Question 2
A 28-year-old marathon runner has a resting heart rate of 48 bpm on ECG. The rhythm is
regular with normal P waves, PR interval 0.14 seconds, and narrow QRS complexes. He
is asymptomatic. Which diagnosis and management are most appropriate?
A. Sinus tachycardia; no treatment needed
B. Sinus bradycardia; no treatment needed [CORRECT]
C. Sinus bradycardia; atropine 0.5 mg IV immediately
D. Third-degree AV block; pacemaker insertion
Rationale: Sinus bradycardia is defined as NSR with rate <60 bpm. In trained athletes,
physiologic sinus bradycardia is common due to increased vagal tone and requires no
treatment if asymptomatic. Atropine (Option C) is indicated only for symptomatic
bradycardia (hypotension, syncope, chest pain, dyspnea, AMS). Third-degree AV block
(Option D) would show AV dissociation with no relationship between P waves and QRS
complexes. The asymptomatic status and athletic conditioning guide expectant
management.
Correct Answer: B
Question 3
A patient on metoprolol presents with fatigue, dizziness, and a heart rate of 52 bpm. BP
is 88/52 mmHg. The ECG shows regular rhythm with upright P waves, PR 0.18 seconds,
and narrow QRS. Which is the FIRST-line treatment?
A. Transcutaneous pacing immediately
B. Atropine 0.5 mg IV [CORRECT]
C. Epinephrine 1 mg IV push
D. Amiodarone 300 mg IV
,Rationale: Symptomatic sinus bradycardia (hypotension, fatigue, dizziness) requires
treatment per ACLS guidelines. First-line is atropine 0.5 mg IV every 3-5 minutes
(maximum 3 mg). Transcutaneous pacing (Option A) is reserved for atropine-refractory
or unstable patients. Epinephrine infusion 2-10 mcg/min (Option C) is second-line if
atropine fails. Amiodarone (Option D) is contraindicated as it would further slow the
heart rate. The beta-blocker effect from metoprolol contributes to the bradycardia.
Correct Answer: B
Question 4
A patient with inferior MI (RCA occlusion) develops sinus bradycardia at 46 bpm with
hypotension (SBP 78 mmHg) and altered mental status. Atropine 3 mg has been given
without effect. What is the next appropriate intervention?
A. Give additional atropine 1 mg IV
B. Initiate transcutaneous pacing [CORRECT]
C. Administer adenosine 6 mg rapid IV push
D. Perform synchronized cardioversion at 50J
Rationale: After maximum atropine dosing (3 mg), symptomatic bradycardia requires
transcutaneous pacing if the patient remains unstable. Inferior MI commonly affects the
RCA, which supplies the SA and AV nodes, causing bradycardia. Additional atropine
(Option A) exceeds the maximum dose. Adenosine (Option C) would worsen
bradycardia and is contraindicated. Synchronized cardioversion (Option D) is for
tachyarrhythmias, not bradycardia. Dopamine 2-10 mcg/kg/min or epinephrine 2-10
mcg/min infusion are alternatives while preparing pacing.
Correct Answer: B
, Question 5
A patient has a heart rate of 140 bpm with regular rhythm, upright P waves in lead II
preceding each QRS, PR interval 0.14 seconds, and narrow QRS complexes. The patient
has a fever of 39°C and is septic. Which diagnosis and treatment are most appropriate?
A. Atrial fibrillation; anticoagulation and rate control
B. Sinus tachycardia; treat underlying sepsis and fever [CORRECT]
C. Supraventricular tachycardia; adenosine 6 mg IV push
D. Ventricular tachycardia; amiodarone 150 mg IV
Rationale: Sinus tachycardia is NSR with rate >100 bpm, typically 100-160 bpm. Fever
increases heart rate approximately 10 bpm per 1°C; 39°C explains the elevated rate.
Treatment targets the underlying cause (sepsis, fever, hypovolemia) rather than the rate.
Atrial fibrillation (Option A) would be irregularly irregular without distinct P waves. SVT
(Option C) would typically have rate >150 bpm with P waves often not visible. VT
(Option D) would show wide QRS complexes. Sinus tachycardia is a compensatory
response, not a primary rhythm disturbance.
Correct Answer: B
Question 6
A patient with anxiety and caffeine overuse presents with palpitations. ECG shows rate
118 bpm, regular rhythm, upright P waves, PR 0.15 seconds, narrow QRS. BP is 132/84
mmHg. The patient is otherwise asymptomatic. Which management is most
appropriate?
A. Immediate synchronized cardioversion
B. Metoprolol 5 mg IV to slow rate
C. Reassurance and avoidance of triggers [CORRECT]
D. Adenosine 6 mg rapid IV push
