RELIAS DYSRHYTHMIA ADVANCED A 2026/2027 |
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Section 1: Advanced Sinus Node & Atrial Dysrhythmias (Q1-15)
Question 1 A 62-year-old patient presents with sudden onset of palpitations. The
ECG shows a regular narrow-complex tachycardia at 130 bpm with P waves identical
in morphology to the patient's baseline sinus P waves. The rhythm terminates
abruptly with carotid sinus massage. What is the most likely diagnosis?
A. Atrial flutter with 2:1 block
B. Sinus node reentrant tachycardia (SNRT)
C. Atrioventricular nodal reentrant tachycardia (AVNRT)
D. Atrial tachycardia with block
Correct Answer: B. Sinus node reentrant tachycardia (SNRT) [CORRECT]
Rationale: SNRT is characterized by paroxysmal onset/termination, P wave
morphology identical to sinus P waves (indicating origin near the sinus node), regular
narrow-complex tachycardia at 100-150 bpm, and response to vagal maneuvers.
Atrial flutter (A) would show sawtooth flutter waves, not sinus P waves. AVNRT (C)
typically shows retrograde P waves or no visible P waves, not sinus morphology.
Atrial tachycardia with block (D) would show abnormal P' morphology and AV block,
not 1:1 conduction with sinus P waves.
Question 2 During continuous ECG monitoring, you observe progressive shortening
of the P-P interval over several beats followed by a pause containing no P wave. The
pause duration is less than twice the shortest P-P interval. What type of sinoatrial exit
block is present?
A. Second-degree SA block type II
B. Third-degree SA block
,C. Second-degree SA block type I (Wenckebach)
D. Sinus arrest
Correct Answer: C. Second-degree SA block type I (Wenckebach) [CORRECT]
Rationale: Second-degree type I SA block demonstrates Wenckebach periodicity
with progressive shortening of the P-P interval before a dropped P wave, and the
pause is less than twice the shortest cycle length. Type II (A) shows constant P-P
intervals before sudden pauses equal to multiples of the baseline P-P interval. Third-
degree block (B) would show complete absence of P waves with an escape rhythm.
Sinus arrest (D) shows pauses not related to multiples of the baseline cycle length.
Question 3 A patient on chronic digoxin therapy presents with nausea and
confusion. The ECG shows atrial rate 200 bpm with regular QRS complexes at 100
bpm. There are visible P waves with abnormal morphology between QRS complexes.
What is the definitive treatment priority?
A. Administer adenosine 6 mg IV push
B. Stop digoxin immediately and check serum level
C. Perform synchronized cardioversion at 100J
D. Start amiodarone 150 mg IV over 10 minutes
Correct Answer: B. Stop digoxin immediately and check serum level [CORRECT]
Rationale: This presentation is classic for nonparoxysmal atrial tachycardia with 2:1
AV block due to digoxin toxicity. The atrial rate of 200 bpm with ventricular rate of
100 bpm indicates 2:1 conduction. Priority is stopping the offending agent, checking
digoxin level, and evaluating potassium and magnesium. Adenosine (A) is
contraindicated in digoxin toxicity. Cardioversion (C) is unnecessary as this is not
unstable VT/VF. Amiodarone (D) may worsen toxicity and is not first-line.
Question 4 A 68-year-old with COPD exacerbation has an irregularly irregular
narrow-complex tachycardia at 120 bpm. The ECG shows at least three distinct P
wave morphologies with varying PR intervals and irregular P-P intervals. No single P
,wave morphology predominates. What is the most appropriate initial
pharmacological intervention?
A. Digoxin loading dose
B. Metoprolol 5 mg IV
C. Verapamil or diltiazem IV
D. Amiodarone 150 mg IV
Correct Answer: C. Verapamil or diltiazem IV [CORRECT]
Rationale: This is multifocal atrial tachycardia (MAT), characterized by ≥3 distinct P'
morphologies, irregularly irregular rhythm, and association with pulmonary disease.
Calcium channel blockers (verapamil/diltiazem) are first-line for rate control. Digoxin
(A) is ineffective and potentially harmful in MAT. Beta-blockers (B) may worsen
bronchospasm in COPD patients. Amiodarone (D) is not first-line and carries
significant toxicity; magnesium replacement should also be initiated.
Question 5 An ECG rhythm strip shows sawtooth flutter waves at 300 bpm with QRS
complexes occurring irregularly at varying intervals. The ventricular rate ranges from
75-150 bpm. What is the mechanism and key clinical implication?
A. Atrial fibrillation with rapid ventricular response
B. Atrial flutter with variable AV block (2:1 to 4:1)
C. Atrial tachycardia with variable block
D. Multifocal atrial tachycardia
Correct Answer: B. Atrial flutter with variable AV block (2:1 to 4:1) [CORRECT]
Rationale: Atrial flutter with variable block demonstrates characteristic sawtooth
flutter waves with irregular ventricular response due to changing AV conduction
ratios (2:1, 3:1, 4:1, etc.). This may mimic atrial fibrillation if flutter waves are small or
hidden in the QRS/T wave. Atrial fibrillation (A) lacks organized atrial activity. Atrial
tachycardia (C) shows discrete P' waves, not sawtooth pattern. MAT (D) requires ≥3
distinct P morphologies, not flutter waves.
, Question 6 A 45-year-old asymptomatic patient has an ECG showing inverted P
waves in leads II, III, and aVF with a PR interval of 0.16 seconds and ventricular rate of
68 bpm. The QRS is narrow. What is the significance and management?
A. Acute inferior myocardial infarction; activate cath lab
B. Ectopic atrial rhythm from low atrial focus; no treatment needed
C. Junctional rhythm with retrograde conduction; atropine indicated
D. WPW syndrome; refer for electrophysiology study
Correct Answer: B. Ectopic atrial rhythm from low atrial focus; no treatment
needed [CORRECT]
Rationale: Low atrial (ectopic atrial) rhythm originates from a low atrial focus,
producing inverted P waves in inferior leads (II, III, aVF) with PR >0.12 sec and rate
50-100 bpm. This is benign and requires no treatment. Inferior MI (A) would show ST
changes, not isolated P wave inversion. Junctional rhythm (C) would have PR <0.12
sec or retrograde P waves after the QRS. WPW (D) shows short PR and delta waves,
not this pattern.
Question 7 A patient with paroxysmal palpitations has an ECG during symptoms
showing regular narrow-complex tachycardia at 140 bpm. The P waves are upright in
lead I and aVF, identical to baseline sinus P waves. The tachycardia starts and stops
abruptly. Which vagal maneuver is most likely to terminate this rhythm?
A. Carotid sinus massage
B. Valsalva maneuver
C. Diving reflex (ice water to face)
D. All of the above are equally effective
Correct Answer: D. All of the above are equally effective [CORRECT]
Rationale: SNRT involves reentry within or near the sinus node and responds to any
vagal maneuver that increases parasympathetic tone and slows SA nodal conduction.
Carotid massage (A), Valsalva (B), and diving reflex (C) all increase vagal tone. While
effectiveness varies individually, all are appropriate first-line interventions for SNRT
before pharmacological therapy (adenosine, beta-blockers, or calcium channel
blockers).
Questions with Complete Solutions | A+ Graded | Pass
Guaranteed - A+ Graded
Section 1: Advanced Sinus Node & Atrial Dysrhythmias (Q1-15)
Question 1 A 62-year-old patient presents with sudden onset of palpitations. The
ECG shows a regular narrow-complex tachycardia at 130 bpm with P waves identical
in morphology to the patient's baseline sinus P waves. The rhythm terminates
abruptly with carotid sinus massage. What is the most likely diagnosis?
A. Atrial flutter with 2:1 block
B. Sinus node reentrant tachycardia (SNRT)
C. Atrioventricular nodal reentrant tachycardia (AVNRT)
D. Atrial tachycardia with block
Correct Answer: B. Sinus node reentrant tachycardia (SNRT) [CORRECT]
Rationale: SNRT is characterized by paroxysmal onset/termination, P wave
morphology identical to sinus P waves (indicating origin near the sinus node), regular
narrow-complex tachycardia at 100-150 bpm, and response to vagal maneuvers.
Atrial flutter (A) would show sawtooth flutter waves, not sinus P waves. AVNRT (C)
typically shows retrograde P waves or no visible P waves, not sinus morphology.
Atrial tachycardia with block (D) would show abnormal P' morphology and AV block,
not 1:1 conduction with sinus P waves.
Question 2 During continuous ECG monitoring, you observe progressive shortening
of the P-P interval over several beats followed by a pause containing no P wave. The
pause duration is less than twice the shortest P-P interval. What type of sinoatrial exit
block is present?
A. Second-degree SA block type II
B. Third-degree SA block
,C. Second-degree SA block type I (Wenckebach)
D. Sinus arrest
Correct Answer: C. Second-degree SA block type I (Wenckebach) [CORRECT]
Rationale: Second-degree type I SA block demonstrates Wenckebach periodicity
with progressive shortening of the P-P interval before a dropped P wave, and the
pause is less than twice the shortest cycle length. Type II (A) shows constant P-P
intervals before sudden pauses equal to multiples of the baseline P-P interval. Third-
degree block (B) would show complete absence of P waves with an escape rhythm.
Sinus arrest (D) shows pauses not related to multiples of the baseline cycle length.
Question 3 A patient on chronic digoxin therapy presents with nausea and
confusion. The ECG shows atrial rate 200 bpm with regular QRS complexes at 100
bpm. There are visible P waves with abnormal morphology between QRS complexes.
What is the definitive treatment priority?
A. Administer adenosine 6 mg IV push
B. Stop digoxin immediately and check serum level
C. Perform synchronized cardioversion at 100J
D. Start amiodarone 150 mg IV over 10 minutes
Correct Answer: B. Stop digoxin immediately and check serum level [CORRECT]
Rationale: This presentation is classic for nonparoxysmal atrial tachycardia with 2:1
AV block due to digoxin toxicity. The atrial rate of 200 bpm with ventricular rate of
100 bpm indicates 2:1 conduction. Priority is stopping the offending agent, checking
digoxin level, and evaluating potassium and magnesium. Adenosine (A) is
contraindicated in digoxin toxicity. Cardioversion (C) is unnecessary as this is not
unstable VT/VF. Amiodarone (D) may worsen toxicity and is not first-line.
Question 4 A 68-year-old with COPD exacerbation has an irregularly irregular
narrow-complex tachycardia at 120 bpm. The ECG shows at least three distinct P
wave morphologies with varying PR intervals and irregular P-P intervals. No single P
,wave morphology predominates. What is the most appropriate initial
pharmacological intervention?
A. Digoxin loading dose
B. Metoprolol 5 mg IV
C. Verapamil or diltiazem IV
D. Amiodarone 150 mg IV
Correct Answer: C. Verapamil or diltiazem IV [CORRECT]
Rationale: This is multifocal atrial tachycardia (MAT), characterized by ≥3 distinct P'
morphologies, irregularly irregular rhythm, and association with pulmonary disease.
Calcium channel blockers (verapamil/diltiazem) are first-line for rate control. Digoxin
(A) is ineffective and potentially harmful in MAT. Beta-blockers (B) may worsen
bronchospasm in COPD patients. Amiodarone (D) is not first-line and carries
significant toxicity; magnesium replacement should also be initiated.
Question 5 An ECG rhythm strip shows sawtooth flutter waves at 300 bpm with QRS
complexes occurring irregularly at varying intervals. The ventricular rate ranges from
75-150 bpm. What is the mechanism and key clinical implication?
A. Atrial fibrillation with rapid ventricular response
B. Atrial flutter with variable AV block (2:1 to 4:1)
C. Atrial tachycardia with variable block
D. Multifocal atrial tachycardia
Correct Answer: B. Atrial flutter with variable AV block (2:1 to 4:1) [CORRECT]
Rationale: Atrial flutter with variable block demonstrates characteristic sawtooth
flutter waves with irregular ventricular response due to changing AV conduction
ratios (2:1, 3:1, 4:1, etc.). This may mimic atrial fibrillation if flutter waves are small or
hidden in the QRS/T wave. Atrial fibrillation (A) lacks organized atrial activity. Atrial
tachycardia (C) shows discrete P' waves, not sawtooth pattern. MAT (D) requires ≥3
distinct P morphologies, not flutter waves.
, Question 6 A 45-year-old asymptomatic patient has an ECG showing inverted P
waves in leads II, III, and aVF with a PR interval of 0.16 seconds and ventricular rate of
68 bpm. The QRS is narrow. What is the significance and management?
A. Acute inferior myocardial infarction; activate cath lab
B. Ectopic atrial rhythm from low atrial focus; no treatment needed
C. Junctional rhythm with retrograde conduction; atropine indicated
D. WPW syndrome; refer for electrophysiology study
Correct Answer: B. Ectopic atrial rhythm from low atrial focus; no treatment
needed [CORRECT]
Rationale: Low atrial (ectopic atrial) rhythm originates from a low atrial focus,
producing inverted P waves in inferior leads (II, III, aVF) with PR >0.12 sec and rate
50-100 bpm. This is benign and requires no treatment. Inferior MI (A) would show ST
changes, not isolated P wave inversion. Junctional rhythm (C) would have PR <0.12
sec or retrograde P waves after the QRS. WPW (D) shows short PR and delta waves,
not this pattern.
Question 7 A patient with paroxysmal palpitations has an ECG during symptoms
showing regular narrow-complex tachycardia at 140 bpm. The P waves are upright in
lead I and aVF, identical to baseline sinus P waves. The tachycardia starts and stops
abruptly. Which vagal maneuver is most likely to terminate this rhythm?
A. Carotid sinus massage
B. Valsalva maneuver
C. Diving reflex (ice water to face)
D. All of the above are equally effective
Correct Answer: D. All of the above are equally effective [CORRECT]
Rationale: SNRT involves reentry within or near the sinus node and responds to any
vagal maneuver that increases parasympathetic tone and slows SA nodal conduction.
Carotid massage (A), Valsalva (B), and diving reflex (C) all increase vagal tone. While
effectiveness varies individually, all are appropriate first-line interventions for SNRT
before pharmacological therapy (adenosine, beta-blockers, or calcium channel
blockers).
