Relias Dysrhythmias Exam B Complete 60 Questions
Relias Dysrhythmia Advanced with Measurements B
Exam Questions and Answers | 100% Pass Guaranteed |
Graded A+
Part 1: ECG Measurements & Rate Calculation (Questions 1-10)
Q1. A 6-second rhythm strip shows 12 QRS complexes. What is the heart rate?
A. 60 bpm
B. 100 bpm
C. 120 bpm
D. 140 bpm
Correct Answer: C. 120 bpm
Rationale: To calculate heart rate on an irregular rhythm, count the number of
QRS complexes in a 6-second strip (30 large boxes) and multiply by 10. 12 × 10 =
120 bpm .
Q2. Using the 1500 method, a regular rhythm has 20 small boxes between R
waves. What is the heart rate?
A. 50 bpm
B. 60 bpm
C. 75 bpm
D. 100 bpm
Correct Answer: C. 75 bpm
Rationale: For regular rhythms, divide 1500 by the number of small boxes
between R waves. 1500 ÷ 20 = 75 bpm .
,Q3. At standard ECG paper speed (25 mm/s), how many seconds are
represented by one large (5 mm) box?
A. 0.04 seconds
B. 0.10 seconds
C. 0.20 seconds
D. 0.40 seconds
Correct Answer: C. 0.20 seconds
Rationale: Each small box = 0.04 seconds. One large box contains 5 small boxes: 5
× 0.04 = 0.20 seconds .
Q4. One small box on ECG paper represents which duration?
A. 0.04 seconds
B. 0.10 seconds
C. 0.20 seconds
D. 0.40 seconds
Correct Answer: A. 0.04 seconds
Rationale: At standard speed (25 mm/s), each 1 mm small box equals 0.04
seconds (40 milliseconds) .
Q5. What is the normal PR interval duration?
A. 0.04-0.10 seconds
B. 0.12-0.20 seconds
C. 0.20-0.30 seconds
D. 0.30-0.40 seconds
Correct Answer: B. 0.12-0.20 seconds
, Rationale: The normal PR interval measures 0.12 to 0.20 seconds (120-200
milliseconds). It represents atrial depolarization and conduction through the AV
node .
Q6. What is the normal QRS duration?
A. Less than 0.12 seconds
B. 0.12-0.20 seconds
C. 0.20-0.30 seconds
D. Greater than 0.20 seconds
Correct Answer: A. Less than 0.12 seconds
Rationale: Normal QRS duration is <0.12 seconds (<120 ms). A QRS ≥0.12 seconds
indicates a ventricular origin or bundle branch block .
Q7. The QT interval should be corrected for heart rate because:
A. QT shortens as heart rate increases
B. QT lengthens as heart rate increases
C. QT is independent of heart rate
D. QTc is always longer than QT
Correct Answer: A. QT shortens as heart rate increases
Rationale: The QT interval varies inversely with heart rate—faster rates shorten
QT, slower rates prolong it. The corrected QT (QTc) adjusts for rate using formulas
like Bazett's .
Q8. A patient's QTc interval is measured at 520 ms. Which of the following is the
most immediate concern?
A. Bradycardia
B. Torsades de pointes
Relias Dysrhythmia Advanced with Measurements B
Exam Questions and Answers | 100% Pass Guaranteed |
Graded A+
Part 1: ECG Measurements & Rate Calculation (Questions 1-10)
Q1. A 6-second rhythm strip shows 12 QRS complexes. What is the heart rate?
A. 60 bpm
B. 100 bpm
C. 120 bpm
D. 140 bpm
Correct Answer: C. 120 bpm
Rationale: To calculate heart rate on an irregular rhythm, count the number of
QRS complexes in a 6-second strip (30 large boxes) and multiply by 10. 12 × 10 =
120 bpm .
Q2. Using the 1500 method, a regular rhythm has 20 small boxes between R
waves. What is the heart rate?
A. 50 bpm
B. 60 bpm
C. 75 bpm
D. 100 bpm
Correct Answer: C. 75 bpm
Rationale: For regular rhythms, divide 1500 by the number of small boxes
between R waves. 1500 ÷ 20 = 75 bpm .
,Q3. At standard ECG paper speed (25 mm/s), how many seconds are
represented by one large (5 mm) box?
A. 0.04 seconds
B. 0.10 seconds
C. 0.20 seconds
D. 0.40 seconds
Correct Answer: C. 0.20 seconds
Rationale: Each small box = 0.04 seconds. One large box contains 5 small boxes: 5
× 0.04 = 0.20 seconds .
Q4. One small box on ECG paper represents which duration?
A. 0.04 seconds
B. 0.10 seconds
C. 0.20 seconds
D. 0.40 seconds
Correct Answer: A. 0.04 seconds
Rationale: At standard speed (25 mm/s), each 1 mm small box equals 0.04
seconds (40 milliseconds) .
Q5. What is the normal PR interval duration?
A. 0.04-0.10 seconds
B. 0.12-0.20 seconds
C. 0.20-0.30 seconds
D. 0.30-0.40 seconds
Correct Answer: B. 0.12-0.20 seconds
, Rationale: The normal PR interval measures 0.12 to 0.20 seconds (120-200
milliseconds). It represents atrial depolarization and conduction through the AV
node .
Q6. What is the normal QRS duration?
A. Less than 0.12 seconds
B. 0.12-0.20 seconds
C. 0.20-0.30 seconds
D. Greater than 0.20 seconds
Correct Answer: A. Less than 0.12 seconds
Rationale: Normal QRS duration is <0.12 seconds (<120 ms). A QRS ≥0.12 seconds
indicates a ventricular origin or bundle branch block .
Q7. The QT interval should be corrected for heart rate because:
A. QT shortens as heart rate increases
B. QT lengthens as heart rate increases
C. QT is independent of heart rate
D. QTc is always longer than QT
Correct Answer: A. QT shortens as heart rate increases
Rationale: The QT interval varies inversely with heart rate—faster rates shorten
QT, slower rates prolong it. The corrected QT (QTc) adjusts for rate using formulas
like Bazett's .
Q8. A patient's QTc interval is measured at 520 ms. Which of the following is the
most immediate concern?
A. Bradycardia
B. Torsades de pointes
