Basic Arrhythmia Sentara - Sinus Rhythms
Exam Questions and Verified Answers with
Rationale Latest Edition 2026/2027
1. Which rhythm strip finding is characterized by a regular
rhythm, rate of 60 to 100 beats per minute, upright P waves
preceding every QRS complex, and a normal PR interval?
A. Normal sinus rhythm
B. Sinus bradycardia
C. Junctional escape rhythm
D. Atrial fibrillation
Correct Answer: A
Rationale: Normal sinus rhythm originates in the sinoatrial
node within the normal 60 to 100 beats per minute range,
featuring consistent, normal P wave morphology and
constant 1:1 AV conduction.
2. What is the defining rhythm characteristic of Sinus
Bradycardia on an ECG monitor?
A. Regular rhythm with a heart rate below 60 beats per minute
and normal P waves
B. Irregular rhythm with absent P waves and a slow ventricular
response
,C. Sawtooth baseline waves with a rate under 50 beats per
minute
D. Wide, bizarre QRS complexes firing at 30 beats per minute
Correct Answer: A
Rationale: Sinus bradycardia shares identical electrical
features with normal sinus rhythm except that the rate
slows below 60 beats per minute due to increased vagal
tone or SA node depression.
3. Which rhythm strip displays a regular rhythm with a
heart rate exceeding 100 beats per minute, upright P waves
preceding every QRS complex, and normal intervals?
A. Sinus tachycardia
B. Paroxysmal supraventricular tachycardia
C. Accelerated idioventricular rhythm
D. Atrial flutter
Correct Answer: A
Rationale: Sinus tachycardia maintains normal sinus node
conduction pathways and morphology, simply accelerating
to a rate above 100 beats per minute due to physiological
stress, fever, or sympathetic stimulation.
4. What is the primary rhythm definition of Sinus
Arrhythmia on an ECG monitor?
,A. An irregular rhythm varying with respiration, featuring
normal P waves and a heart rate between 60 and 100 beats per
minute
B. A completely chaotic rhythm with absent P waves and
irregularly irregular intervals
C. A slow rhythm with progressive PR lengthening and dropped
beats
D. A rapid regular rhythm with hidden P waves
Correct Answer: A
Rationale: Sinus arrhythmia is a normal physiological
variation where heart rate accelerates slightly during
inspiration and slows during expiration, driven by vagal
nerve tone changes associated with breathing.
5. Which rhythm strip shows a temporary pause in sinus
node activity where the missing P-QRS-T cycle is an exact
multiple of the underlying R-R interval?
A. Sinus exit block
B. Sinus arrest
C. Third-degree AV block
D. First-degree AV block
Correct Answer: A
Rationale: Sinus exit block involves failure of the impulse to
exit the SA node into the atrial tissue, resulting in a pause
, that equals an exact mathematical multiple of the normal
cycle length.
6. What distinguishes Sinus Arrest from Sinus Exit Block on
a rhythm strip?
A. Sinus arrest pauses are not exact multiples of the underlying
R-R interval, whereas sinus exit block pauses are exact
multiples.
B. Sinus arrest features wide QRS complexes during the pause.
C. Sinus exit block completely destroys all subsequent P waves.
D. Sinus arrest only occurs during atrial fibrillation.
Correct Answer: A
Rationale: Because sinus arrest represents a temporary
cessation or failure of SA node firing, the resulting pause
does not mathematically match the underlying rhythm
cycle length, unlike a sinus exit block.
7. Which condition describes sick sinus syndrome where
episodes of severe sinus bradycardia alternate with periods
of atrial tachyarrhythmias?
A. Tachycardia-bradycardia syndrome (Tachy-Brady syndrome)
B. First-degree AV block
C. Wolff-Parkinson-White syndrome
D. Brugada syndrome
Exam Questions and Verified Answers with
Rationale Latest Edition 2026/2027
1. Which rhythm strip finding is characterized by a regular
rhythm, rate of 60 to 100 beats per minute, upright P waves
preceding every QRS complex, and a normal PR interval?
A. Normal sinus rhythm
B. Sinus bradycardia
C. Junctional escape rhythm
D. Atrial fibrillation
Correct Answer: A
Rationale: Normal sinus rhythm originates in the sinoatrial
node within the normal 60 to 100 beats per minute range,
featuring consistent, normal P wave morphology and
constant 1:1 AV conduction.
2. What is the defining rhythm characteristic of Sinus
Bradycardia on an ECG monitor?
A. Regular rhythm with a heart rate below 60 beats per minute
and normal P waves
B. Irregular rhythm with absent P waves and a slow ventricular
response
,C. Sawtooth baseline waves with a rate under 50 beats per
minute
D. Wide, bizarre QRS complexes firing at 30 beats per minute
Correct Answer: A
Rationale: Sinus bradycardia shares identical electrical
features with normal sinus rhythm except that the rate
slows below 60 beats per minute due to increased vagal
tone or SA node depression.
3. Which rhythm strip displays a regular rhythm with a
heart rate exceeding 100 beats per minute, upright P waves
preceding every QRS complex, and normal intervals?
A. Sinus tachycardia
B. Paroxysmal supraventricular tachycardia
C. Accelerated idioventricular rhythm
D. Atrial flutter
Correct Answer: A
Rationale: Sinus tachycardia maintains normal sinus node
conduction pathways and morphology, simply accelerating
to a rate above 100 beats per minute due to physiological
stress, fever, or sympathetic stimulation.
4. What is the primary rhythm definition of Sinus
Arrhythmia on an ECG monitor?
,A. An irregular rhythm varying with respiration, featuring
normal P waves and a heart rate between 60 and 100 beats per
minute
B. A completely chaotic rhythm with absent P waves and
irregularly irregular intervals
C. A slow rhythm with progressive PR lengthening and dropped
beats
D. A rapid regular rhythm with hidden P waves
Correct Answer: A
Rationale: Sinus arrhythmia is a normal physiological
variation where heart rate accelerates slightly during
inspiration and slows during expiration, driven by vagal
nerve tone changes associated with breathing.
5. Which rhythm strip shows a temporary pause in sinus
node activity where the missing P-QRS-T cycle is an exact
multiple of the underlying R-R interval?
A. Sinus exit block
B. Sinus arrest
C. Third-degree AV block
D. First-degree AV block
Correct Answer: A
Rationale: Sinus exit block involves failure of the impulse to
exit the SA node into the atrial tissue, resulting in a pause
, that equals an exact mathematical multiple of the normal
cycle length.
6. What distinguishes Sinus Arrest from Sinus Exit Block on
a rhythm strip?
A. Sinus arrest pauses are not exact multiples of the underlying
R-R interval, whereas sinus exit block pauses are exact
multiples.
B. Sinus arrest features wide QRS complexes during the pause.
C. Sinus exit block completely destroys all subsequent P waves.
D. Sinus arrest only occurs during atrial fibrillation.
Correct Answer: A
Rationale: Because sinus arrest represents a temporary
cessation or failure of SA node firing, the resulting pause
does not mathematically match the underlying rhythm
cycle length, unlike a sinus exit block.
7. Which condition describes sick sinus syndrome where
episodes of severe sinus bradycardia alternate with periods
of atrial tachyarrhythmias?
A. Tachycardia-bradycardia syndrome (Tachy-Brady syndrome)
B. First-degree AV block
C. Wolff-Parkinson-White syndrome
D. Brugada syndrome
