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Chapter 11 Test — Bradyarrhythmias: Sinus Node Dysfunction, AV Blocks and Escape Rhythms
26 questions · 26 min · +4 / -1
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Question 1
Question 1
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Which of the following statements about sick sinus syndrome is
UNTRUE
?
A.
It occurs most commonly in the elderly
B.
Coronary artery disease is a common cause
C.
The ECG abnormalities are often intermittent
D.
Most symptomatic patients will eventually require permanent pacing
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Question 2
Question 2
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The primary (definitive) therapeutic intervention in
symptomatic
sinoatrial node dysfunction is:
A.
IV atropine boluses
B.
IV isoprenaline infusion
C.
Permanent pacemaker implantation
D.
Long-term oral theophylline therapy
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Question 3
Question 3
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In which of the following causes of SA node dysfunction may permanent pacing
NOT
be required?
1. Beta-blocker drugs
2. Narcotic drugs
3. Iatrogenic — post-radiotherapy / post-surgery
4. Hypothyroidism
5. Sick sinus syndrome
6. Raised intracranial pressure
A.
1, 2, 3 and 4
B.
1, 2, 4 and 5
C.
1, 2, 4 and 6
D.
3, 5 and 6
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Question 4
Question 4
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A 68-year-old woman has recurrent dizzy spells. Her rhythm strip shows a baseline P-P interval of 800 ms interrupted by a sudden pause of exactly 1600 ms, after which the sinus rhythm resumes at the original rate. What is the most likely mechanism?
A.
Mobitz type II second-degree AV block
B.
Second-degree sinoatrial (SA) exit block
C.
Sinus arrest, in which the SA node fails to generate an impulse at all
D.
A blocked (non-conducted) premature atrial complex
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Question 5
Question 5
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A 74-year-old man with paroxysmal atrial fibrillation is started on a beta-blocker for rate control and shortly afterwards has a syncopal episode. Monitoring shows a 5-second pause occurring immediately after an episode of atrial fibrillation terminates. Which statement about his management is correct?
A.
The beta-blocker alone is sufficient; the pause will settle
B.
The pause is physiological and needs no specific action
C.
Long-term oral atropine is the treatment of choice
D.
Tachy-brady syndrome, requiring a permanent pacemaker
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Question 6
Question 6
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A 22-year-old competitive marathon runner has a routine ECG for a sports medical. He is entirely asymptomatic with a blood pressure of 118/74 mmHg and excellent exercise tolerance. The ECG shows sinus rhythm at 44/min with a normal P wave before every QRS and a PR interval of 180 ms. What is the most appropriate action?
A.
Start oral theophylline to raise his resting heart rate
B.
Refer for permanent pacemaker implantation
C.
Give atropine 1 mg IV to raise the rate
D.
Reassure and discharge; no treatment is required
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Question 7
Question 7
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The treatment of
asymptomatic
bradycardia is:
A.
No treatment is required
B.
Atropine
C.
Isoprenaline
D.
Cardiac pacing
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Question 8
Question 8
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In complete heart block, which fibres take over after a period of asystole to produce an idioventricular rhythm?
A.
SA node
B.
Purkinje fibres
C.
Bundle of His
D.
AV node
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Question 9
Question 9
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The rhythm strip shown is from a 70-year-old man. After a sinus beat there is a long pause, followed by slow, wide, bizarre QRS complexes at about 30/min with no preceding P waves. He is hypotensive and drowsy. What is the most appropriate management?
A.
Synchronised DC cardioversion
B.
Transcutaneous pacing, with transvenous pacing to follow
C.
IV amiodarone bolus
D.
IV lidocaine to suppress the wide complexes
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Question 10
Question 10
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In the tracing shown, sinus beats are followed by a long pause that is terminated by a beat with no preceding P wave and a QRS identical in width to the sinus beats (labelled 'Junctional Escape'). Which statement about this beat is correct?
A.
It is an early (premature) beat and should be suppressed with an antiarrhythmic
B.
It indicates an infranodal block and always carries a wide QRS
C.
It is a late escape beat arising from the AV junction at 40-60/min
D.
It confirms accelerated idioventricular rhythm
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Question 11
Question 11
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The rhythm strip shown is a regular
wide-QRS
rhythm without visible P waves at a rate of roughly 90/min, recorded minutes after successful thrombolysis for STEMI. This accelerated idioventricular rhythm (AIVR) is most characteristically associated with:
A.
Dilated cardiomyopathy
B.
Myocardial reperfusion
C.
Digitalis intoxication
D.
Myocarditis
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Question 12
Question 12
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A 72-year-old man on digoxin for heart failure is found to have a regular narrow-QRS rhythm at 80/min with no discernible P waves. Serum potassium is 3.1 mmol/L. Which rhythm is this and what does it suggest?
A.
Accelerated junctional rhythm, suggesting digoxin toxicity
B.
Normal junctional escape rhythm, which needs no explanation
C.
Sinus tachycardia due to decompensated heart failure
D.
Ventricular escape rhythm requiring urgent pacing
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Question 13
Question 13
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A 62-year-old man presents with recurrent fainting episodes. His ECG shows P waves at 75/min and narrow QRS complexes at 35/min, with no relationship between the P waves and the QRS complexes. The clinical diagnosis is:
A.
Second-degree AV block
B.
Atrial tachycardia
C.
First-degree AV block
D.
Stokes-Adams syndrome
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Question 14
Question 14
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An 80-year-old man presents with syncope. On the rhythm strip shown, the arrows mark P waves (upward) and R waves (downward). The P-P interval is regular at 800 ms and the R-R interval is regular at 1500 ms, with no consistent relationship between them. The
most appropriate immediate
management is:
A.
Atropine 1 mg IV, followed by temporary pacing
B.
Digoxin to slow the ventricular rate
C.
IV adenosine 6 mg bolus to assess conduction
D.
Oral bisoprolol to enhance vagal tone
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Question 15
Question 15
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A 68-year-old man presents with recurrent syncope and a heart rate of 36/min. His 12-lead ECG shows regular P waves at 72/min with no fixed relationship to the QRS complexes, which occur at 36/min with a slightly widened morphology; the PR interval is completely variable. He had an anterior myocardial infarction 3 weeks ago. What is the
definitive
management?
A.
IV atropine 0.6 mg bolus
B.
Temporary transvenous pacemaker insertion
C.
Permanent pacemaker implantation
D.
IV isoprenaline infusion
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Question 16
Question 16
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A 64-year-old man with an inferior-wall myocardial infarction one year ago presents with palpitations and recurrent syncope. His resting ECG is unremarkable. A 24-hour Holter recording captures sinus pauses of up to 4.5 seconds and episodes of high-grade AV block, occurring at the same times as his syncopal episodes. What is the recommended long-term treatment?
A.
Long-term oral amiodarone
B.
Atropine as required
C.
Permanent pacemaker implantation
D.
Atropine and isoproterenol infusions
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Question 17
Question 17
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A 60-year-old woman has an ECG showing sinus rhythm at 70/min with a constant PR interval of 180 ms and intermittent, sudden non-conducted P waves. The QRS duration is 140 ms. She has no symptoms. What is the correct management?
A.
Referral for permanent pacemaker implantation
B.
Start a beta-blocker to stabilise the rhythm
C.
Atropine 1 mg IV and discharge
D.
Observation only, since she is asymptomatic
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Question 18
Question 18
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A 24-year-old man from a rural area presents with a 2-week history of a flu-like illness after a camping trip, and now has presyncope. His ECG shows complete heart block with a junctional escape at 45/min. He recalls an expanding circular rash on his thigh. What is the most appropriate management?
A.
Long-term amiodarone therapy
B.
Reassurance and discharge with routine outpatient follow-up
C.
Immediate permanent pacemaker implantation
D.
Antibiotic therapy, with temporary pacing if needed
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Question 19
Question 19
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A patient with digoxin toxicity has a pulse of 54/min and ECG evidence of third-degree heart block. What is the best treatment?
A.
Digoxin immune Fab
B.
Lidocaine
C.
DC shock
D.
Phenytoin
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Question 20
Question 20
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In the treatment of severe symptomatic bradycardia, all of the following are appropriate
EXCEPT
:
A.
Atropine
B.
Cardiac pacing
C.
Isoproterenol
D.
Diltiazem
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Question 21
Question 21
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A patient with an acute inferior myocardial infarction develops symptomatic sinus bradycardia with hypotension. The initial treatment of choice is:
A.
Atropine
B.
Digoxin
C.
A calcium channel blocker
D.
Propranolol
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Question 22
Question 22
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Which of the following bradyarrhythmias is
LEAST
likely to respond to intravenous atropine?
A.
Symptomatic sinus bradycardia
B.
Complete AV block with a wide-QRS ventricular escape at 30/min
C.
Complete AV block with a narrow-QRS junctional escape at 45/min
D.
Mobitz type I (Wenckebach) second-degree AV block
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Question 23
Question 23
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A 78-year-old woman has recurrent syncope. Her Holter shows episodes of sinus arrest with pauses, the longest measuring 4 seconds, each corresponding to a blackout. She is on no rate-slowing drugs and her thyroid function is normal. Which statement is correct?
A.
Long-term oral atropine is the treatment of choice
B.
The finding is only significant if the pause exceeds 10 seconds
C.
Pauses of any length are physiological during the day and need no action
D.
Symptomatic pauses over 3 seconds warrant permanent pacing
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Question 24
Question 24
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Giant 'a' waves in the jugular venous pulse occur in all of the following
EXCEPT
:
A.
Junctional rhythm
B.
Pulmonary hypertension
C.
Tricuspid regurgitation
D.
Complete heart block
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Question 25
Question 25
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Which of the following endocrine conditions is a recognised, often reversible cause of bradycardia and AV block?
A.
Hypothyroidism
B.
Cushing syndrome
C.
Hyperthyroidism
D.
Phaeochromocytoma
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Question 26
Question 26
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A neonate born to a mother positive for anti-Ro/SSA and anti-La/SSB antibodies is at greatest risk of developing which cardiac abnormality?
A.
Tetralogy of Fallot
B.
Patent ductus arteriosus
C.
Wolff-Parkinson-White syndrome
D.
Congenital complete (third-degree) heart block
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