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Chapter 21 Test — Channelopathies and Pre-Excitation Syndromes
29 questions · 29 min · +4 / -1
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Question 1
Question 1
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A 25-year-old man collapsed while playing a football match. He has had several fainting episodes in the past. His resting 12-lead ECG is shown. What is the most likely diagnosis?
A.
Atrial flutter
B.
Atrial fibrillation
C.
Wolff-Parkinson-White syndrome
D.
Sinus tachycardia
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Question 2
Question 2
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A 24-year-old man with episodic palpitations and two prior syncopal episodes has the resting ECG shown — a short PR interval (<120 ms), a slurred initial upstroke of the QRS (delta wave) and a QRS duration >120 ms. Echocardiography is normal. Which arrhythmia carries the GREATEST risk of sudden cardiac death in this patient?
A.
Orthodromic AVRT causing a rapid narrow-complex SVT
B.
Antidromic AVRT mimicking ventricular tachycardia
C.
Atrial fibrillation with rapid accessory-pathway conduction
D.
Atrial flutter with 1:1 accessory-pathway conduction
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Question 3
Question 3
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The ECG shown was recorded from a haemodynamically stable young man with known Wolff-Parkinson-White syndrome who developed sudden palpitations: a very fast, irregularly irregular wide-complex tachycardia with beat-to-beat variation in QRS morphology. Which drug is the treatment of choice?
A.
Digoxin
B.
Procainamide
C.
Verapamil
D.
Adenosine
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Question 4
Question 4
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The most common re-entrant tachycardia associated with WPW syndrome is:
A.
Orthodromic AV re-entrant tachycardia
B.
Antidromic AV re-entrant tachycardia
C.
Rapidly conducting atrial fibrillation
D.
Atrial flutter with 2:1 block
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Question 5
Question 5
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A haemodynamically stable patient with known WPW presents with a regular broad-complex tachycardia which is shown to be antidromic AV re-entrant tachycardia. What is the optimal management?
A.
Oral verapamil
B.
Oral beta-blocker
C.
Immediate defibrillation
D.
Intravenous procainamide
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Question 6
Question 6
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A 22-year-old man with WPW undergoes an electrophysiology study to characterise conduction through his accessory pathway in both antegrade and retrograde directions. Which statement about accessory-pathway conduction is FALSE?
A.
The Bundle of Kent can conduct antegrade
B.
Concealed pathways conduct only retrogradely
C.
Antegrade conduction causes pre-excitation
D.
Retrograde conduction causes pre-excitation
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Question 7
Question 7
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All of the following are true about the condition diagnosed by an ECG showing a
short PR interval with a delta wave and a widened QRS
, EXCEPT:
A.
It is a congenital condition
B.
It can be seen in completely asymptomatic individuals
C.
Its prevalence increases with age
D.
It is caused by an abnormal accessory pathway
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Question 8
Question 8
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Congenital heart disease classically associated with ventricular pre-excitation is:
A.
Atrial septal defect
B.
Bicuspid aortic valve
C.
Ebstein anomaly
D.
Patent ductus arteriosus
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Question 9
Question 9
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A 25-year-old man presents with palpitations and recurrent syncope. His brother died suddenly. Examination is normal. His ECG (shown) demonstrates a PR interval of 100 ms with a completely normal, narrow QRS and no delta wave. What is the most likely diagnosis?
A.
Wolff-Parkinson-White syndrome
B.
Lown-Ganong-Levine syndrome
C.
Long QT syndrome
D.
Brugada syndrome
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Question 10
Question 10
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A 50-year-old man is admitted with chest discomfort. His ECG shows a right bundle branch block-like appearance with ST elevation confined to leads V1, V2 and V3. There is no evidence of myocardial infarction, and no true RBBB. Which condition could be a threat to his life?
A.
WPW syndrome
B.
AV nodal re-entrant tachycardia
C.
Hyperkalaemia
D.
Brugada syndrome
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Question 11
Question 11
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A 15-year-old boy is brought to the emergency department in the early morning after his father found him with agonal respiration. BP is 80/50 mmHg with no palpable pulse. A sibling died suddenly. Genetic workup shows a loss-of-function mutation in the SCN5A gene. Which ECG pattern is expected?
A.
ST elevation with a coved pattern in V1-V2
B.
ST elevation with a Pardee sign (convex, with reciprocal changes)
C.
Downsloping ST depression
D.
Upsloping ST depression
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Question 12
Question 12
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A 10-year-old boy's father noticed agonal respiration at 5 AM while the boy was asleep. He was rushed to the emergency department and the ECG shown (leads V1-V3) was recorded. What is the most likely diagnosis?
A.
Early repolarisation syndrome
B.
Brugada syndrome
C.
Hypertrophic cardiomyopathy
D.
Atrial fibrillation
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Question 13
Question 13
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A 32-year-old man is referred after his brother died suddenly at age 28. His ECG shows a coved pattern in V1-V2: J-point elevation ≥2 mm with a convex, dome-shaped ST segment followed by a negative T wave, present spontaneously without drug provocation. Echocardiography is normal. Which is the most ominous arrhythmia this ECG predisposes to?
A.
Atrial fibrillation with rapid ventricular response
B.
Polymorphic ventricular tachycardia
C.
Complete AV block with ventricular escape
D.
AV re-entry tachycardia via an accessory pathway
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Question 14
Question 14
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A 16-year-old girl has recurrent exercise-induced syncope. Her ECG (shown) demonstrates marked QT prolongation, and audiometry reveals no hearing deficit. This presentation is consistent with Romano-Ward syndrome. Which best describes this condition?
A.
Congenital short PR associated with deafness
B.
Congenital long QT without deafness
C.
Congenital long QT associated with cataract
D.
Congenital short PR without cataract
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Question 15
Question 15
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A 14-year-old boy is brought to the emergency department after a syncopal episode while swimming in a school pool; he was resuscitated by the lifeguard. His elder brother died suddenly at 18 during a football match, and his mother takes beta-blockers for a cardiac condition. Examination is unremarkable. ECG shows a QTc of 520 ms with broad-based T waves. Genetic testing reveals a loss-of-function mutation in KCNQ1. What is the most likely diagnosis?
A.
Long QT syndrome type 1
B.
Brugada syndrome
C.
Catecholaminergic polymorphic ventricular tachycardia
D.
Hypertrophic cardiomyopathy
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Question 16
Question 16
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The figure shows the three Brugada ECG patterns. Which statement is correct?
A.
The Type 3 pattern is diagnostic only if the ST elevation exceeds 1 mm
B.
The saddleback Type 2 pattern is diagnostic of Brugada syndrome on its own
C.
The coved Type 1 pattern is diagnostic of Brugada syndrome on its own
D.
All three patterns are equally diagnostic
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Question 17
Question 17
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A 34-year-old man is evaluated after an episode of unexplained syncope. His ECG shows a saddleback ST-segment elevation in V2 with a positive T wave (Type II Brugada pattern). Echocardiography is normal. What is the most appropriate next step to establish the diagnosis?
A.
Reassure the patient — a saddleback pattern excludes Brugada syndrome
B.
Implant an ICD immediately
C.
Start quinidine and repeat the ECG in one week
D.
Perform a provocative drug challenge with IV ajmaline or flecainide
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Question 18
Question 18
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A 28-year-old man of Southeast Asian origin is admitted with a febrile illness (39.5 °C) and has a syncopal episode on the ward. His ECG now shows coved ST elevation in V1-V2 with T-wave inversion, which was not present on a previous tracing. Which of the following best explains this finding?
A.
Fever impairs sodium channel function and unmasks the Brugada pattern
B.
Fever causes acute myocarditis with pericardial ST elevation
C.
Fever causes hyperkalaemia which mimics Brugada
D.
Fever prolongs the QT interval and produces coved ST elevation
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Question 19
Question 19
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Which drug is the only pharmacological agent proven to reduce arrhythmia burden in Brugada syndrome, and by what mechanism?
A.
Verapamil — by blocking L-type calcium channels
B.
Flecainide — by blocking the sodium current
C.
Amiodarone — by prolonging the action potential and refractory period
D.
Quinidine — by blocking the transient outward current (I
to
)
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Question 20
Question 20
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A 19-year-old woman with congenital long QT syndrome has always had her syncopal episodes triggered by the sound of her alarm clock or a sudden telephone ring. Her ECG shows low-amplitude, notched T waves. Which gene is most likely mutated?
A.
KCNQ1 (IKs)
B.
RYR2 (ryanodine receptor)
C.
SCN5A (INa)
D.
KCNH2 (IKr)
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Question 21
Question 21
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The characteristic T-wave morphologies of the three main congenital long QT subtypes are shown. For the subtype in the
third panel
(long isoelectric ST segment with a late-appearing T wave), which treatment is most appropriate?
A.
Deliberate induction of bradycardia with digoxin
B.
Mexiletine, with an ICD for high-risk patients
C.
Beta-blockers alone are highly effective
D.
Verapamil
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Question 22
Question 22
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Mutations in the
SCN5A
gene can cause both Brugada syndrome and long QT syndrome type 3. Which statement correctly describes this relationship?
A.
Both are loss-of-function mutations, differing only in penetrance
B.
Brugada is a loss-of-function mutation; LQT3 is a gain-of-function mutation
C.
Brugada is a gain-of-function mutation; LQT3 is a loss-of-function mutation
D.
SCN5A codes for a potassium channel in Brugada and a sodium channel in LQT3
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Question 23
Question 23
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A 14-year-old boy collapses during a physical education class and is resuscitated. His resting 12-lead ECG in the emergency department is completely normal, as is his echocardiogram. What is the most appropriate next investigation?
A.
24-hour ambulatory blood pressure monitoring
B.
Exercise stress testing
C.
Reassure and discharge — the normal ECG excludes a cardiac cause
D.
Coronary angiography
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Question 24
Question 24
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During exercise testing, a 12-year-old girl with recurrent exertional syncope develops ventricular ectopy that progresses to a ventricular tachycardia in which the QRS axis alternates from beat to beat. Her resting ECG and echocardiogram are normal. Which is the first-line treatment?
A.
Quinidine
B.
Amiodarone
C.
Beta-blockers (nadolol)
D.
Mexiletine
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Question 25
Question 25
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A 20-year-old woman with known congenital long QT syndrome becomes dizzy and the monitor shows the rhythm illustrated — a polymorphic ventricular tachycardia whose QRS complexes twist around the isoelectric baseline. She has a palpable pulse and a systolic BP of 100 mmHg. What is the first-line treatment?
A.
IV magnesium sulfate 2 g over 1-2 minutes
B.
Oral propranolol 40 mg three times daily
C.
IV amiodarone 300 mg over 20 minutes
D.
IV adenosine 6 mg by rapid bolus
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Question 26
Question 26
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The ECG of a 22-year-old asymptomatic athlete is shown. It demonstrates J-point elevation with notching, concave ('smiley') ST elevation and tall concordant T waves in the lateral leads. Which feature, if present, would classify this early repolarisation pattern as HIGH risk?
A.
Inferior-lead J-point elevation with a horizontal ST segment
B.
J-point elevation confined to the lateral leads V4-V6
C.
A rapidly ascending ST segment after the J point
D.
Notching rather than slurring of the J wave in the lateral leads
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Question 27
Question 27
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A 19-year-old man is investigated after a resuscitated cardiac arrest. He has no structural heart disease. His ECG shows a QTc of 320 ms with tall, narrow, peaked T waves and virtually no ST segment. What is the most likely diagnosis and definitive treatment?
A.
Brugada syndrome — quinidine alone
B.
Hypocalcaemia — IV calcium gluconate
C.
Early repolarisation syndrome — reassurance
D.
Short QT syndrome — ICD implantation
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Question 28
Question 28
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In a patient with the Wolff-Parkinson-White pattern, the delta wave is clearly
positive (upright) in lead V1
. What does this indicate?
A.
An atrio-His (James) fibre
B.
A concealed accessory pathway
C.
A left-sided accessory pathway (Type A WPW)
D.
A right-sided accessory pathway (Type B WPW)
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Question 29
Question 29
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A 26-year-old woman with WPW syndrome has had three episodes of symptomatic AVRT in the past year. What is the definitive management?
A.
Radiofrequency catheter ablation
B.
Lifelong verapamil
C.
Lifelong digoxin
D.
Implantable cardioverter-defibrillator
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