ANSWERS 2026/2027 (BASIC A DYSRHYTHMIA)
250-Question Exam-Aligned Practice Bank
Practice bank: These are original exam-aligned questions, not copied or leaked Relias assessment items.
Cardiac conduction pathway reference diagram
1. On standard ECG paper, one small horizontal box represents:
☑ 0.04 seconds
• 0.10 seconds
• 0.20 seconds
• 0.40 seconds
Rationale: At standard speed 25 mm/s, each 1-mm small box is 0.04 s.
2. On standard ECG paper, one large box represents:
• 0.04 seconds
• 0.10 seconds
☑ 0.20 seconds
• 0.40 seconds
Rationale: A large box is five small boxes, or 0.20 s.
3. A normal PR interval is best defined as:
• 0.04–0.08 s
☑ 0.12–0.20 s
• 0.22–0.30 s
• 0.32–0.40 s
Rationale: The normal PR interval is 0.12–0.20 s.
4. A QRS duration of 0.16 seconds is described as:
• Narrow
☑ Prolonged/wide
• Absent
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, • Shortened
Rationale: A QRS ≥0.12 s is considered wide.
5. The P wave primarily represents:
☑ Atrial depolarization
• Atrial repolarization
• Ventricular depolarization
• Ventricular repolarization
Rationale: The P wave reflects atrial depolarization.
6. The QRS complex primarily represents:
• Atrial depolarization
☑ Ventricular depolarization
• Atrial repolarization
• Ventricular repolarization
Rationale: The QRS reflects ventricular depolarization.
7. The T wave represents:
• Atrial depolarization
• Ventricular depolarization
☑ Ventricular repolarization
• AV nodal conduction
Rationale: The T wave reflects ventricular repolarization.
8. A regular rhythm with 8 QRS complexes in a 6-second strip has an approximate rate of:
• 40 bpm
• 60 bpm
☑ 80 bpm
• 120 bpm
Rationale: Multiply the number of QRS complexes by 10: 8 × 10 = 80 bpm.
9. A regular rhythm with R-R intervals of 4 large boxes has an approximate rate of:
• 50 bpm
☑ 75 bpm
• 100 bpm
• 150 bpm
Rationale: For a regular rhythm, 300 ÷ 4 = 75 bpm.
10. A regular rhythm with R-R intervals of 2 large boxes has an approximate rate of:
• 75 bpm
• 100 bpm
☑ 150 bpm
• 200 bpm
Rationale: For a regular rhythm, 300 ÷ 2 = 150 bpm.
11. Which feature is most important when determining whether a ventricular rhythm is regular?
• P-wave amplitude
☑ R-R interval consistency
• T-wave polarity
• PR interval alone
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, Rationale: Regularity is assessed by comparing successive R-R intervals.
12. A normal sinus P wave should generally be:
• Absent
• Identical and inverted in every lead
☑ Upright and consistent before each QRS in appropriate leads
• Wide and not related to QRS complexes
Rationale: Sinus P waves are consistent and precede each QRS.
13. Which finding most strongly suggests sinus origin?
☑ P waves have a consistent relationship to QRS complexes
• QRS complexes are always wide
• The ventricular rate exceeds 200 bpm
• No atrial activity is visible
Rationale: Sinus rhythm has organized atrial activity preceding ventricular depolarization.
14. If a rhythm is too irregular for the 300-box method, the preferred quick rate method is:
☑ Count QRS in 6 seconds and multiply by 10
• Count P waves in 1 large box
• Multiply large boxes by 10
• Measure one PR interval
Rationale: The 6-second method is useful for irregular rhythms.
15. The ECG calibration mark of 10 mm/mV means:
☑ 10 mm vertically equals 1 mV
• 10 mm horizontally equals 1 second
• 1 mm vertically equals 10 mV
• 1 large box equals 1 mV
Rationale: Standard calibration is 10 mm per mV.
ECG reference: normal sinus rhythm
16. Which interval reflects conduction from atria through the AV node and His-Purkinje system to
ventricular depolarization?
• QT
☑ PR
• ST
• RR
Rationale: The PR interval reflects atrial-to-ventricular conduction time.
17. The QT interval represents:
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, • Atrial depolarization only
☑ Ventricular depolarization and repolarization
• AV nodal delay only
• Atrial repolarization only
Rationale: QT spans ventricular depolarization through repolarization.
18. A strip with no identifiable P waves and irregularly irregular R-R intervals is most consistent
with:
☑ Atrial fibrillation
• Sinus bradycardia
• First-degree AV block
• Junctional rhythm
Rationale: A-fib classically has absent organized P waves and an irregularly irregular ventricular rhythm.
19. Saw-tooth atrial activity is classically associated with:
☑ Atrial flutter
• Atrial fibrillation
• Ventricular fibrillation
• Sinus tachycardia
Rationale: Flutter waves create the characteristic saw-tooth pattern.
20. A rhythm with a ventricular rate of 40 bpm, narrow QRS, and absent/retrograde P waves most
strongly suggests:
☑ Junctional escape rhythm
• Ventricular tachycardia
• Atrial flutter
• Sinus tachycardia
Rationale: A junctional escape rhythm commonly has a rate of 40–60 bpm and narrow QRS complexes.
21. A sinus rhythm at 54 bpm with upright P waves before every QRS and PR 0.16 s is:
• Normal sinus rhythm
☑ Sinus bradycardia
• Sinus tachycardia
• Atrial fibrillation
Rationale: Sinus bradycardia is sinus rhythm with a rate below 60 bpm.
22. A sinus rhythm at 118 bpm with normal P waves and narrow QRS complexes is:
• Sinus bradycardia
• Normal sinus rhythm
☑ Sinus tachycardia
• Atrial flutter
Rationale: Sinus tachycardia is sinus rhythm with a rate above 100 bpm.
23. A patient with sinus bradycardia is dizzy and hypotensive. The priority is to:
• Ignore the rhythm because it is always benign
☑ Assess perfusion and follow the symptomatic bradycardia protocol
• Give a beta blocker
• Encourage the patient to ambulate
Rationale: Treatment is guided by symptoms and perfusion, not the ECG label alone.
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