Basic Arrhythmia & Cardiac Rhythm Analysis QUESTION
Bank | Practice ECGs, Clinical Scenarios & Rationales
2026/2027
QUESTION 1 What is the standard "6-second strip method" formula
used to calculate the approximate ventricular heart rate on a rhythm
strip?
A. Count the number of R waves in a 6-second strip and multiply by 10
B. Count the number of small boxes between two R waves and divide
into 1500
C. Count the number of large boxes between two R waves and divide
into 300
D. Count the total number of P waves in one minute and divide by 2
Correct Answer: A. Count the number of R waves in a 6-second strip
and multiply by 10
Detailed Rationale: Standard ECG paper runs at 25 mm per second,
meaning a 10 cm strip represents 6 seconds of time. Multiplying the
number of R waves found in this window by 10 yields the beats per
minute.
QUESTION 2 How is the rapid calculation method used to determine
heart rate using large boxes between consecutive R waves?
A. Memorize the sequence: 300, 150, 100, 75, 60, 50 corresponding to
1, 2, 3, 4, 5, and 6 large boxes apart
B. Multiply the number of large boxes by 10
,C. Divide 1500 by the number of large boxes
D. Count the number of R waves in 3 seconds and multiply by 20
Correct Answer: A. Memorize the sequence: 300, 150, 100, 75, 60, 50
corresponding to 1, 2, 3, 4, 5, and 6 large boxes apart
Detailed Rationale: Since each large box represents 0.20 seconds,
dividing 300 (the number of large boxes in one minute) by the number
of large boxes between R waves gives a quick estimation for regular
rhythms.
QUESTION 3 What is the precise calculation method using small boxes
to determine heart rate on a standard ECG?
A. Divide 1500 by the total number of small boxes between two
consecutive R waves
B. Divide 300 by the number of small boxes
C. Multiply the number of small boxes by 0.04
D. Count small boxes in 10 seconds and multiply by 6
Correct Answer: A. Divide 1500 by the total number of small boxes
between two consecutive R waves
Detailed Rationale: There are 1500 small boxes in one minute (25
mm/sec multiplied by 60 seconds = 1500 mm). Dividing 1,500 by the
small-box count between R-R intervals yields an exact heart rate.
QUESTION 4 What are the standard five systematic steps recommended
for analyzing any cardiac rhythm strip?
A. Rate, Rhythm, P waves, PR interval, and QRS complex duration
B. Age, gender, blood pressure, temperature, and heart rate
,C. ST segment, T wave, U wave, QT interval, and axis
D. Lead placement, paper speed, voltage calibration, baseline wander,
and artifact
Correct Answer: A. Rate, Rhythm, P waves, PR interval, and QRS
complex duration
Detailed Rationale: A methodical 5-step approach ensures no clinical
details are missed, allowing systematic evaluation of rate, regularity,
atrial activity, conduction time, and ventricular depolarization width.
QUESTION 5 How is rhythm regularity determined when analyzing an R-
R interval on an ECG?
A. Measure the distance between consecutive R waves across the entire
strip using calipers or paper marks to check if they occur at consistent
intervals
B. Count the total number of P waves in 10 seconds
C. Measure the height of the T waves in lead II
D. Check the PR interval duration in lead V1
Correct Answer: A. Measure the distance between consecutive R waves
across the entire strip using calipers or paper marks to check if they
occur at consistent intervals
Detailed Rationale: A regular rhythm has consistent R-R intervals
(varying by less than 0.08 seconds or 2 small boxes), whereas an
irregular rhythm has varying intervals.
QUESTION 6 What defines a normal sinus rhythm originating from the
sinoatrial (SA) node?
, A. Regular rhythm, rate of 60 to 100 bpm, upright P waves in lead II
preceding every QRS, PR interval of 0.12 to 0.20 seconds, and QRS
width under 0.12 seconds
B. Irregular rhythm with absent P waves and wide QRS complexes
C. Rate below 60 bpm with inverted P waves
D. Sawtooth baseline pattern with rapid ventricular response
Correct Answer: A. Regular rhythm, rate of 60 to 100 bpm, upright P
waves in lead II preceding every QRS, PR interval of 0.12 to 0.20
seconds, and QRS width under 0.12 seconds
Detailed Rationale: Normal sinus rhythm represents normal electrical
activation sequence originating in the SA node within standard
electrophysiological parameters.
QUESTION 7 What heart rate criteria characterize Sinus Bradycardia?
A. Less than 60 beats per minute with normal sinus morphology
B. Between 60 and 100 beats per minute
C. Greater than 100 beats per minute
D. Exactly 40 beats per minute with wide complexes
Correct Answer: A. Less than 60 beats per minute with normal sinus
morphology
Detailed Rationale: Sinus bradycardia retains normal P-wave and QRS
configurations but fires at an intrinsic rate slower than 60 beats per
minute.
QUESTION 8 What characterizes Sinus Tachycardia on an ECG monitor?
Bank | Practice ECGs, Clinical Scenarios & Rationales
2026/2027
QUESTION 1 What is the standard "6-second strip method" formula
used to calculate the approximate ventricular heart rate on a rhythm
strip?
A. Count the number of R waves in a 6-second strip and multiply by 10
B. Count the number of small boxes between two R waves and divide
into 1500
C. Count the number of large boxes between two R waves and divide
into 300
D. Count the total number of P waves in one minute and divide by 2
Correct Answer: A. Count the number of R waves in a 6-second strip
and multiply by 10
Detailed Rationale: Standard ECG paper runs at 25 mm per second,
meaning a 10 cm strip represents 6 seconds of time. Multiplying the
number of R waves found in this window by 10 yields the beats per
minute.
QUESTION 2 How is the rapid calculation method used to determine
heart rate using large boxes between consecutive R waves?
A. Memorize the sequence: 300, 150, 100, 75, 60, 50 corresponding to
1, 2, 3, 4, 5, and 6 large boxes apart
B. Multiply the number of large boxes by 10
,C. Divide 1500 by the number of large boxes
D. Count the number of R waves in 3 seconds and multiply by 20
Correct Answer: A. Memorize the sequence: 300, 150, 100, 75, 60, 50
corresponding to 1, 2, 3, 4, 5, and 6 large boxes apart
Detailed Rationale: Since each large box represents 0.20 seconds,
dividing 300 (the number of large boxes in one minute) by the number
of large boxes between R waves gives a quick estimation for regular
rhythms.
QUESTION 3 What is the precise calculation method using small boxes
to determine heart rate on a standard ECG?
A. Divide 1500 by the total number of small boxes between two
consecutive R waves
B. Divide 300 by the number of small boxes
C. Multiply the number of small boxes by 0.04
D. Count small boxes in 10 seconds and multiply by 6
Correct Answer: A. Divide 1500 by the total number of small boxes
between two consecutive R waves
Detailed Rationale: There are 1500 small boxes in one minute (25
mm/sec multiplied by 60 seconds = 1500 mm). Dividing 1,500 by the
small-box count between R-R intervals yields an exact heart rate.
QUESTION 4 What are the standard five systematic steps recommended
for analyzing any cardiac rhythm strip?
A. Rate, Rhythm, P waves, PR interval, and QRS complex duration
B. Age, gender, blood pressure, temperature, and heart rate
,C. ST segment, T wave, U wave, QT interval, and axis
D. Lead placement, paper speed, voltage calibration, baseline wander,
and artifact
Correct Answer: A. Rate, Rhythm, P waves, PR interval, and QRS
complex duration
Detailed Rationale: A methodical 5-step approach ensures no clinical
details are missed, allowing systematic evaluation of rate, regularity,
atrial activity, conduction time, and ventricular depolarization width.
QUESTION 5 How is rhythm regularity determined when analyzing an R-
R interval on an ECG?
A. Measure the distance between consecutive R waves across the entire
strip using calipers or paper marks to check if they occur at consistent
intervals
B. Count the total number of P waves in 10 seconds
C. Measure the height of the T waves in lead II
D. Check the PR interval duration in lead V1
Correct Answer: A. Measure the distance between consecutive R waves
across the entire strip using calipers or paper marks to check if they
occur at consistent intervals
Detailed Rationale: A regular rhythm has consistent R-R intervals
(varying by less than 0.08 seconds or 2 small boxes), whereas an
irregular rhythm has varying intervals.
QUESTION 6 What defines a normal sinus rhythm originating from the
sinoatrial (SA) node?
, A. Regular rhythm, rate of 60 to 100 bpm, upright P waves in lead II
preceding every QRS, PR interval of 0.12 to 0.20 seconds, and QRS
width under 0.12 seconds
B. Irregular rhythm with absent P waves and wide QRS complexes
C. Rate below 60 bpm with inverted P waves
D. Sawtooth baseline pattern with rapid ventricular response
Correct Answer: A. Regular rhythm, rate of 60 to 100 bpm, upright P
waves in lead II preceding every QRS, PR interval of 0.12 to 0.20
seconds, and QRS width under 0.12 seconds
Detailed Rationale: Normal sinus rhythm represents normal electrical
activation sequence originating in the SA node within standard
electrophysiological parameters.
QUESTION 7 What heart rate criteria characterize Sinus Bradycardia?
A. Less than 60 beats per minute with normal sinus morphology
B. Between 60 and 100 beats per minute
C. Greater than 100 beats per minute
D. Exactly 40 beats per minute with wide complexes
Correct Answer: A. Less than 60 beats per minute with normal sinus
morphology
Detailed Rationale: Sinus bradycardia retains normal P-wave and QRS
configurations but fires at an intrinsic rate slower than 60 beats per
minute.
QUESTION 8 What characterizes Sinus Tachycardia on an ECG monitor?
