1
DYSRHYTHMIAS COMPLETE SOLUTIONS 2026/2027 |
Including EKG Strips | Verified Rhythm Interpretation | Basic
& Advanced | Pass Guaranteed - A+ Graded
Section 1: Sinus Dysrhythmias & Normal Variants (Q1-12)
Q1. A 42-year-old male presents for a pre-operative evaluation. The EKG strip shows:
upright P waves preceding every QRS complex in lead II; R-R intervals regular at 4
large boxes; PR interval constant at 0.16 seconds; QRS duration 0.08 seconds; ST
segment isoelectric; T waves upright. What is the rhythm interpretation?
A. Sinus bradycardia with first-degree AV block
B. Normal sinus rhythm
C. Junctional escape rhythm
D. Sinus arrhythmia
B. Normal sinus rhythm [CORRECT]
Rationale: The rhythm meets all criteria for normal sinus rhythm: regular rate of 75
bpm (300/4), upright P waves in lead II preceding each QRS, normal PR interval (0.12-
0.20 sec), narrow QRS (<0.12 sec), and isoelectric ST segment. Option A is incorrect
because the PR interval is normal and the rate is not <60 bpm. Option C is incorrect
because junctional rhythms have absent, inverted, or retrograde P waves. Option D is
incorrect because the R-R intervals are regular without respiratory variation.
Correct Answer: B
Q2. A 68-year-old patient on beta-blocker therapy has a heart rate of 52 bpm. The
EKG shows upright P waves in lead II before each QRS, normal PR interval, and
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narrow QRS complexes. What is the primary treatment per 2026/2027 ACLS
guidelines if the patient is hypotensive (SBP 78/42) and altered?
A. Immediate synchronized cardioversion
B. Atropine 1 mg IV, repeat every 3-5 minutes to a maximum of 3 mg
C. Adenosine 6 mg rapid IV push
D. Amiodarone 300 mg IV push
B. Atropine 1 mg IV, repeat every 3-5 minutes to a maximum of 3 mg [CORRECT]
Rationale: Symptomatic sinus bradycardia is treated with atropine as the first-line
agent per ACLS guidelines. If atropine is ineffective, transcutaneous pacing or
dopamine/epinephrine infusions are indicated. Cardioversion (A) is inappropriate for
non-tachycardic rhythms. Adenosine (C) would worsen bradycardia. Amiodarone (D)
is indicated for ventricular tachycardia, not bradycardia.
Correct Answer: B
Q3. A 28-year-old athlete presents with a resting heart rate of 58 bpm. The EKG
demonstrates regular rhythm, normal P wave morphology, PR interval 0.14 seconds,
and QRS 0.09 seconds. The patient is asymptomatic with normal blood pressure.
What is the appropriate management?
A. Immediate transcutaneous pacing
B. Discontinue all physical activity permanently
C. Observation; no treatment required
D. Atropine 0.5 mg IV push
C. Observation; no treatment required [CORRECT]
Rationale: Asymptomatic sinus bradycardia in a healthy athlete is a normal
physiologic adaptation from increased vagal tone and requires no intervention.
Transcutaneous pacing (A) and atropine (D) are reserved for symptomatic or
hemodynamically unstable bradycardia. Discontinuing activity (B) is unnecessary
without symptoms.
Correct Answer: C
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Q4. A patient with fever and sepsis has a heart rate of 118 bpm. The EKG shows
upright P waves in lead II preceding each QRS, PR interval 0.15 seconds, and narrow
QRS complexes. The rhythm is regular. Which statement is most accurate?
A. This is atrial fibrillation requiring anticoagulation
B. This is sinus tachycardia; treat the underlying cause
C. This is junctional tachycardia requiring adenosine
D. This is ventricular tachycardia requiring amiodarone
B. This is sinus tachycardia; treat the underlying cause [CORRECT]
Rationale: Sinus tachycardia is characterized by a rate >100 bpm with normal P wave
morphology and axis, normal PR interval, and narrow QRS complexes. The
appropriate management is treating the underlying cause (sepsis/fever). AFib (A)
would be irregularly irregular without distinct P waves. Junctional tachycardia (C)
would have absent, inverted, or retrograde P waves. VT (D) would have wide QRS
complexes.
Correct Answer: B
Q5. A 72-year-old patient on digoxin presents with dizziness. The EKG strip shows:
regular sinus rhythm at 68 bpm, then a pause with no P wave, QRS, or T wave during
the pause. After the pause, the sinus rhythm resumes at 68 bpm. The pause duration
is exactly twice the preceding P-P interval. What is the rhythm?
A. Second-degree AV block Type I
B. Sinus arrest with junctional escape
C. Sinoatrial exit block Type II
D. Ventricular standstill
C. Sinoatrial exit block Type II [CORRECT]
Rationale: SA exit block Type II is characterized by a sudden absence of P-QRS-T
complexes where the pause duration is an exact multiple (usually 2×) of the
underlying P-P interval, indicating the sinus impulse failed to depolarize the atria.
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Sinus arrest (B) would have a pause that is not a multiple of the baseline P-P interval.
Second-degree AV block Type I (A) shows progressive PR prolongation before a
dropped QRS, not absent P waves. Ventricular standstill (D) would show P waves
without QRS complexes.
Correct Answer: C
Q6. A 35-year-old patient has a heart rate that varies from 68 bpm during expiration
to 88 bpm during inspiration. The EKG shows normal P waves, normal PR interval,
and narrow QRS with gradually shortening and lengthening R-R intervals
corresponding to respiration. What is this rhythm?
A. Atrial fibrillation
B. Sinus arrhythmia
C. Sinus tachycardia with PACs
D. Second-degree AV block Type I
B. Sinus arrhythmia [CORRECT]
Rationale: Sinus arrhythmia is a normal variant characterized by phasic variation in
heart rate with respiration (inspiration increases rate, expiration decreases rate) due
to changes in vagal tone. All other parameters (P waves, PR interval, QRS) remain
normal. AFib (A) would be irregularly irregular without consistent P waves. PACs (C)
would cause premature beats with abnormal P wave morphology. Wenckebach (D)
shows progressive PR prolongation before a dropped beat.
Correct Answer: B
Q7. Using the 6-second method, a nurse counts 9 QRS complexes within a 6-second
strip. What is the calculated heart rate?
A. 60 bpm
B. 72 bpm
DYSRHYTHMIAS COMPLETE SOLUTIONS 2026/2027 |
Including EKG Strips | Verified Rhythm Interpretation | Basic
& Advanced | Pass Guaranteed - A+ Graded
Section 1: Sinus Dysrhythmias & Normal Variants (Q1-12)
Q1. A 42-year-old male presents for a pre-operative evaluation. The EKG strip shows:
upright P waves preceding every QRS complex in lead II; R-R intervals regular at 4
large boxes; PR interval constant at 0.16 seconds; QRS duration 0.08 seconds; ST
segment isoelectric; T waves upright. What is the rhythm interpretation?
A. Sinus bradycardia with first-degree AV block
B. Normal sinus rhythm
C. Junctional escape rhythm
D. Sinus arrhythmia
B. Normal sinus rhythm [CORRECT]
Rationale: The rhythm meets all criteria for normal sinus rhythm: regular rate of 75
bpm (300/4), upright P waves in lead II preceding each QRS, normal PR interval (0.12-
0.20 sec), narrow QRS (<0.12 sec), and isoelectric ST segment. Option A is incorrect
because the PR interval is normal and the rate is not <60 bpm. Option C is incorrect
because junctional rhythms have absent, inverted, or retrograde P waves. Option D is
incorrect because the R-R intervals are regular without respiratory variation.
Correct Answer: B
Q2. A 68-year-old patient on beta-blocker therapy has a heart rate of 52 bpm. The
EKG shows upright P waves in lead II before each QRS, normal PR interval, and
,2
narrow QRS complexes. What is the primary treatment per 2026/2027 ACLS
guidelines if the patient is hypotensive (SBP 78/42) and altered?
A. Immediate synchronized cardioversion
B. Atropine 1 mg IV, repeat every 3-5 minutes to a maximum of 3 mg
C. Adenosine 6 mg rapid IV push
D. Amiodarone 300 mg IV push
B. Atropine 1 mg IV, repeat every 3-5 minutes to a maximum of 3 mg [CORRECT]
Rationale: Symptomatic sinus bradycardia is treated with atropine as the first-line
agent per ACLS guidelines. If atropine is ineffective, transcutaneous pacing or
dopamine/epinephrine infusions are indicated. Cardioversion (A) is inappropriate for
non-tachycardic rhythms. Adenosine (C) would worsen bradycardia. Amiodarone (D)
is indicated for ventricular tachycardia, not bradycardia.
Correct Answer: B
Q3. A 28-year-old athlete presents with a resting heart rate of 58 bpm. The EKG
demonstrates regular rhythm, normal P wave morphology, PR interval 0.14 seconds,
and QRS 0.09 seconds. The patient is asymptomatic with normal blood pressure.
What is the appropriate management?
A. Immediate transcutaneous pacing
B. Discontinue all physical activity permanently
C. Observation; no treatment required
D. Atropine 0.5 mg IV push
C. Observation; no treatment required [CORRECT]
Rationale: Asymptomatic sinus bradycardia in a healthy athlete is a normal
physiologic adaptation from increased vagal tone and requires no intervention.
Transcutaneous pacing (A) and atropine (D) are reserved for symptomatic or
hemodynamically unstable bradycardia. Discontinuing activity (B) is unnecessary
without symptoms.
Correct Answer: C
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Q4. A patient with fever and sepsis has a heart rate of 118 bpm. The EKG shows
upright P waves in lead II preceding each QRS, PR interval 0.15 seconds, and narrow
QRS complexes. The rhythm is regular. Which statement is most accurate?
A. This is atrial fibrillation requiring anticoagulation
B. This is sinus tachycardia; treat the underlying cause
C. This is junctional tachycardia requiring adenosine
D. This is ventricular tachycardia requiring amiodarone
B. This is sinus tachycardia; treat the underlying cause [CORRECT]
Rationale: Sinus tachycardia is characterized by a rate >100 bpm with normal P wave
morphology and axis, normal PR interval, and narrow QRS complexes. The
appropriate management is treating the underlying cause (sepsis/fever). AFib (A)
would be irregularly irregular without distinct P waves. Junctional tachycardia (C)
would have absent, inverted, or retrograde P waves. VT (D) would have wide QRS
complexes.
Correct Answer: B
Q5. A 72-year-old patient on digoxin presents with dizziness. The EKG strip shows:
regular sinus rhythm at 68 bpm, then a pause with no P wave, QRS, or T wave during
the pause. After the pause, the sinus rhythm resumes at 68 bpm. The pause duration
is exactly twice the preceding P-P interval. What is the rhythm?
A. Second-degree AV block Type I
B. Sinus arrest with junctional escape
C. Sinoatrial exit block Type II
D. Ventricular standstill
C. Sinoatrial exit block Type II [CORRECT]
Rationale: SA exit block Type II is characterized by a sudden absence of P-QRS-T
complexes where the pause duration is an exact multiple (usually 2×) of the
underlying P-P interval, indicating the sinus impulse failed to depolarize the atria.
, 4
Sinus arrest (B) would have a pause that is not a multiple of the baseline P-P interval.
Second-degree AV block Type I (A) shows progressive PR prolongation before a
dropped QRS, not absent P waves. Ventricular standstill (D) would show P waves
without QRS complexes.
Correct Answer: C
Q6. A 35-year-old patient has a heart rate that varies from 68 bpm during expiration
to 88 bpm during inspiration. The EKG shows normal P waves, normal PR interval,
and narrow QRS with gradually shortening and lengthening R-R intervals
corresponding to respiration. What is this rhythm?
A. Atrial fibrillation
B. Sinus arrhythmia
C. Sinus tachycardia with PACs
D. Second-degree AV block Type I
B. Sinus arrhythmia [CORRECT]
Rationale: Sinus arrhythmia is a normal variant characterized by phasic variation in
heart rate with respiration (inspiration increases rate, expiration decreases rate) due
to changes in vagal tone. All other parameters (P waves, PR interval, QRS) remain
normal. AFib (A) would be irregularly irregular without consistent P waves. PACs (C)
would cause premature beats with abnormal P wave morphology. Wenckebach (D)
shows progressive PR prolongation before a dropped beat.
Correct Answer: B
Q7. Using the 6-second method, a nurse counts 9 QRS complexes within a 6-second
strip. What is the calculated heart rate?
A. 60 bpm
B. 72 bpm
