Basic Arrhythmia & ECG Interpretation Exam |
Comprehensive Practice Test & Detailed Rationales
2026/2027
QUESTION 1
What is the standard time duration represented by a single small
horizontal box on standard ECG graph paper?
A. 0.04 seconds
B. 0.10 seconds
C. 0.20 seconds
D. 1.00 second
Correct Answer: A. 0.04 seconds
Detailed Rationale: Standard ECG paper moves at a speed of 25 mm/s.
Each small box represents 1 millimeter horizontally, which translates to
a time duration of 0.04 seconds.
QUESTION 2
What time duration is represented by a single large box (comprising 5
by 5 small boxes) on standard ECG graph paper?
A. 0.20 seconds
B. 0.05 seconds
C. 0.50 seconds
D. 1.00 second
,Correct Answer: A. 0.20 seconds
Detailed Rationale: Since each small box represents 0.04 seconds, a
large box containing five small boxes horizontally equals 5 × 0.04 =
0.20 seconds.
QUESTION 3
What voltage magnitude is typically represented by one large vertical
box (5 small boxes high) when standard calibration is applied?
A. 0.5 millivolts (0.5 mV)
B. 0.1 millivolts (0.1 mV)
C. 1.0 millivolts (1.0 mV)
D. 5.0 millivolts (5.0 mV)
Correct Answer: A. 0.5 millivolts (0.5 mV)
Detailed Rationale: On standard ECG calibration, each small vertical box
represents 0.1 mV, so a large box spanning 5 small boxes vertically
equals 0.5 mV (two large boxes equal 1.0 mV).
QUESTION 4
What is the intrinsic firing rate range of the Sinoatrial (SA) node when
functioning as the primary pacemaker of the heart?
A. 60 to 100 beats per minute
B. 40 to 60 beats per minute
C. 20 to 40 beats per minute
D. 100 to 150 beats per minute
Correct Answer: A. 60 to 100 beats per minute
,Detailed Rationale: The SA node normally paces the heart at an
intrinsic rate of 60 to 100 beats per minute, establishing the baseline for
normal sinus rhythm.
QUESTION 5
What is the inherent backup firing rate range of the Atrioventricular
(AV) junctional pacemaker?
A. 40 to 60 beats per minute
B. 60 to 100 beats per minute
C. 20 to 40 beats per minute
D. 100 to 120 beats per minute
Correct Answer: A. 40 to 60 beats per minute
Detailed Rationale: When the SA node fails, the secondary pacemaker
cells in the AV junction take over, firing at an intrinsic rate of 40 to 60
beats per minute.
QUESTION 6
What is the intrinsic backup firing rate range of the ventricular
pacemaker system (idioventricular rate)?
A. 20 to 40 beats per minute
B. 40 to 60 beats per minute
C. 60 to 80 beats per minute
D. 80 to 100 beats per minute
Correct Answer: A. 20 to 40 beats per minute
, Detailed Rationale: The ventricular conduction system serves as the
final tertiary pacemaker backup, firing at a slow intrinsic rate of 20 to 40
beats per minute.
QUESTION 7
What specific criteria define a Normal Sinus Rhythm (NSR) on an ECG?
A. Regular rhythm, rate between 60 and 100 bpm, upright P waves in
leads II, III, and aVF preceding every narrow QRS complex, with constant
PR and QT intervals.
B. Irregular rhythm with rate exceeding 100 bpm and absent P waves.
C. Slow regular rhythm below 60 bpm with wide bizarre QRS complexes.
D. Sawtooth baseline flutter waves with variable ventricular response.
Correct Answer: A. Regular rhythm, rate between 60 and 100 bpm,
upright P waves in leads II, III, and aVF preceding every narrow QRS
complex, with constant PR and QT intervals.
Detailed Rationale: NSR requires normal sinus node initiation, normal
rates, consistent P wave morphology, and normal AV conduction
parameters.
QUESTION 8
What characterizes Sinus Bradycardia on a rhythm strip?
A. A regular rhythm with all parameters of normal sinus rhythm except
a heart rate below 60 beats per minute.
B. An irregular rhythm exceeding 100 beats per minute with inverted P
waves.
Comprehensive Practice Test & Detailed Rationales
2026/2027
QUESTION 1
What is the standard time duration represented by a single small
horizontal box on standard ECG graph paper?
A. 0.04 seconds
B. 0.10 seconds
C. 0.20 seconds
D. 1.00 second
Correct Answer: A. 0.04 seconds
Detailed Rationale: Standard ECG paper moves at a speed of 25 mm/s.
Each small box represents 1 millimeter horizontally, which translates to
a time duration of 0.04 seconds.
QUESTION 2
What time duration is represented by a single large box (comprising 5
by 5 small boxes) on standard ECG graph paper?
A. 0.20 seconds
B. 0.05 seconds
C. 0.50 seconds
D. 1.00 second
,Correct Answer: A. 0.20 seconds
Detailed Rationale: Since each small box represents 0.04 seconds, a
large box containing five small boxes horizontally equals 5 × 0.04 =
0.20 seconds.
QUESTION 3
What voltage magnitude is typically represented by one large vertical
box (5 small boxes high) when standard calibration is applied?
A. 0.5 millivolts (0.5 mV)
B. 0.1 millivolts (0.1 mV)
C. 1.0 millivolts (1.0 mV)
D. 5.0 millivolts (5.0 mV)
Correct Answer: A. 0.5 millivolts (0.5 mV)
Detailed Rationale: On standard ECG calibration, each small vertical box
represents 0.1 mV, so a large box spanning 5 small boxes vertically
equals 0.5 mV (two large boxes equal 1.0 mV).
QUESTION 4
What is the intrinsic firing rate range of the Sinoatrial (SA) node when
functioning as the primary pacemaker of the heart?
A. 60 to 100 beats per minute
B. 40 to 60 beats per minute
C. 20 to 40 beats per minute
D. 100 to 150 beats per minute
Correct Answer: A. 60 to 100 beats per minute
,Detailed Rationale: The SA node normally paces the heart at an
intrinsic rate of 60 to 100 beats per minute, establishing the baseline for
normal sinus rhythm.
QUESTION 5
What is the inherent backup firing rate range of the Atrioventricular
(AV) junctional pacemaker?
A. 40 to 60 beats per minute
B. 60 to 100 beats per minute
C. 20 to 40 beats per minute
D. 100 to 120 beats per minute
Correct Answer: A. 40 to 60 beats per minute
Detailed Rationale: When the SA node fails, the secondary pacemaker
cells in the AV junction take over, firing at an intrinsic rate of 40 to 60
beats per minute.
QUESTION 6
What is the intrinsic backup firing rate range of the ventricular
pacemaker system (idioventricular rate)?
A. 20 to 40 beats per minute
B. 40 to 60 beats per minute
C. 60 to 80 beats per minute
D. 80 to 100 beats per minute
Correct Answer: A. 20 to 40 beats per minute
, Detailed Rationale: The ventricular conduction system serves as the
final tertiary pacemaker backup, firing at a slow intrinsic rate of 20 to 40
beats per minute.
QUESTION 7
What specific criteria define a Normal Sinus Rhythm (NSR) on an ECG?
A. Regular rhythm, rate between 60 and 100 bpm, upright P waves in
leads II, III, and aVF preceding every narrow QRS complex, with constant
PR and QT intervals.
B. Irregular rhythm with rate exceeding 100 bpm and absent P waves.
C. Slow regular rhythm below 60 bpm with wide bizarre QRS complexes.
D. Sawtooth baseline flutter waves with variable ventricular response.
Correct Answer: A. Regular rhythm, rate between 60 and 100 bpm,
upright P waves in leads II, III, and aVF preceding every narrow QRS
complex, with constant PR and QT intervals.
Detailed Rationale: NSR requires normal sinus node initiation, normal
rates, consistent P wave morphology, and normal AV conduction
parameters.
QUESTION 8
What characterizes Sinus Bradycardia on a rhythm strip?
A. A regular rhythm with all parameters of normal sinus rhythm except
a heart rate below 60 beats per minute.
B. An irregular rhythm exceeding 100 beats per minute with inverted P
waves.
