Basic Arrhythmia Sentara Test [2026] | 200 Practice
Questions with Detailed Answer Explanations | Bold Italic
Answers & Italic Rationales | EKG Telemetry Certification
Study Guide | pdf
Domain 1: ECG Basics, Waveforms & Measurements
(Questions 1–30)
1. A nurse is reviewing the electrophysiology of the heart
and correctly identifies which structure as the primary
pacemaker of a normal, healthy human heart?
A) Atrioventricular node
B) Sinoatrial node
C) Bundle of His
D) Purkinje fiber network
Answer: B) Sinoatrial node
Explanation: The sinoatrial node is located in the upper wall
of the right atrium and possesses the fastest intrinsic firing
rate, making it the dominant natural pacemaker of the heart
under normal physiological conditions.
2. A telemetry technician observes an ECG strip and
correctly recognizes that the P wave represents which
specific electrophysiological event?
A) Ventricular depolarization
B) Atrial depolarization
C) Ventricular repolarization
D) Atrial repolarization
Answer: B) Atrial depolarization
Explanation: The P wave represents atrial depolarization,
,which corresponds to atrial contraction. It reflects the
electrical impulse spreading through the atria from the SA
node and is the first waveform seen on the ECG tracing.
3. When analyzing a rhythm strip, a monitor technician
identifies the QRS complex as representing which of the
following cardiac electrical events?
A) Atrial depolarization
B) Ventricular repolarization
C) Ventricular depolarization
D) Purkinje fiber repolarization
Answer: C) Ventricular depolarization
Explanation: The QRS complex represents ventricular
depolarization, which triggers ventricular contraction. This
is the largest waveform on the ECG because the ventricles
have more muscle mass than the atria.
4. A nurse educator is teaching new staff about normal ECG
intervals and correctly states that the normal PR interval in
an adult measures which range?
A) 0.06-0.10 seconds
B) 0.12-0.20 seconds
C) 0.20-0.32 seconds
D) 0.32-0.44 seconds
Answer: B) 0.12-0.20 seconds
Explanation: The normal PR interval is 0.12-0.20 seconds (3-
5 small squares). It represents the time from the start of
atrial depolarization to the start of ventricular
depolarization, and a prolonged PR interval greater than
0.20 seconds indicates first-degree AV block.
5. A monitor technician is measuring the QRS duration on a
rhythm strip and correctly identifies the normal range for an
,adult as which of the following?
A) 0.12-0.20 seconds
B) 0.06-0.12 seconds
C) 0.04-0.06 seconds
D) 0.20-0.32 seconds
Answer: B) 0.06-0.12 seconds
Explanation: The normal QRS duration is 0.06-0.12 seconds
(1.5-3 small squares). A QRS greater than 0.12 seconds
indicates a bundle branch block, ventricular origin of the
impulse, or an intraventricular conduction delay.
6. A nurse is reviewing ECG measurements and correctly
identifies the normal duration of the QT interval in an adult
as which range?
A) 0.12-0.20 seconds
B) 0.06-0.12 seconds
C) 0.32-0.44 seconds
D) 0.44-0.52 seconds
Answer: C) 0.32-0.44 seconds
Explanation: The normal QT interval is 0.32-0.44 seconds
and varies with heart rate. It represents ventricular
depolarization and repolarization, and should be less than
half the R-R interval for a normal QT.
7. On a standard ECG grid, a telemetry technician correctly
identifies that one small horizontal box represents how
much time?
A) 0.01 seconds
B) 0.04 seconds
C) 0.20 seconds
D) 0.50 seconds
, Answer: B) 0.04 seconds
Explanation: One small horizontal box on standard ECG
paper represents 0.04 seconds at a paper speed of 25
mm/s. This is a fundamental measurement for calculating
intervals and heart rate.
8. A nurse is using the 1500 method to calculate heart rate
on a regular rhythm and correctly identifies which constant
is divided by the number of small boxes?
A) 300
B) 1500
C) 3000
D) 10 inches
Answer: B) 1500
Explanation: The 1500 method divides the constant 1500
(representing the number of small boxes in one minute at
standard 25 mm/s paper speed) by the total number of small
boxes between consecutive R waves to yield an accurate
heart rate for regular rhythms.
9. A monitor technician is using the large box method to
calculate heart rate and correctly divides which number by
the large boxes between R waves?
A) Divide 1500 by the number of small boxes
B) Divide 300 by the number of large boxes
C) Multiply the number of R waves in a six-second strip by 10
D) Count the total number of P waves in one minute
Answer: B) Divide 300 by the number of large boxes
Explanation: The large box method divides the constant 300
by the number of large squares separating consecutive R
waves, corresponding to rates of 300, 150, 100, 75, 60, and
50 beats per minute.
Questions with Detailed Answer Explanations | Bold Italic
Answers & Italic Rationales | EKG Telemetry Certification
Study Guide | pdf
Domain 1: ECG Basics, Waveforms & Measurements
(Questions 1–30)
1. A nurse is reviewing the electrophysiology of the heart
and correctly identifies which structure as the primary
pacemaker of a normal, healthy human heart?
A) Atrioventricular node
B) Sinoatrial node
C) Bundle of His
D) Purkinje fiber network
Answer: B) Sinoatrial node
Explanation: The sinoatrial node is located in the upper wall
of the right atrium and possesses the fastest intrinsic firing
rate, making it the dominant natural pacemaker of the heart
under normal physiological conditions.
2. A telemetry technician observes an ECG strip and
correctly recognizes that the P wave represents which
specific electrophysiological event?
A) Ventricular depolarization
B) Atrial depolarization
C) Ventricular repolarization
D) Atrial repolarization
Answer: B) Atrial depolarization
Explanation: The P wave represents atrial depolarization,
,which corresponds to atrial contraction. It reflects the
electrical impulse spreading through the atria from the SA
node and is the first waveform seen on the ECG tracing.
3. When analyzing a rhythm strip, a monitor technician
identifies the QRS complex as representing which of the
following cardiac electrical events?
A) Atrial depolarization
B) Ventricular repolarization
C) Ventricular depolarization
D) Purkinje fiber repolarization
Answer: C) Ventricular depolarization
Explanation: The QRS complex represents ventricular
depolarization, which triggers ventricular contraction. This
is the largest waveform on the ECG because the ventricles
have more muscle mass than the atria.
4. A nurse educator is teaching new staff about normal ECG
intervals and correctly states that the normal PR interval in
an adult measures which range?
A) 0.06-0.10 seconds
B) 0.12-0.20 seconds
C) 0.20-0.32 seconds
D) 0.32-0.44 seconds
Answer: B) 0.12-0.20 seconds
Explanation: The normal PR interval is 0.12-0.20 seconds (3-
5 small squares). It represents the time from the start of
atrial depolarization to the start of ventricular
depolarization, and a prolonged PR interval greater than
0.20 seconds indicates first-degree AV block.
5. A monitor technician is measuring the QRS duration on a
rhythm strip and correctly identifies the normal range for an
,adult as which of the following?
A) 0.12-0.20 seconds
B) 0.06-0.12 seconds
C) 0.04-0.06 seconds
D) 0.20-0.32 seconds
Answer: B) 0.06-0.12 seconds
Explanation: The normal QRS duration is 0.06-0.12 seconds
(1.5-3 small squares). A QRS greater than 0.12 seconds
indicates a bundle branch block, ventricular origin of the
impulse, or an intraventricular conduction delay.
6. A nurse is reviewing ECG measurements and correctly
identifies the normal duration of the QT interval in an adult
as which range?
A) 0.12-0.20 seconds
B) 0.06-0.12 seconds
C) 0.32-0.44 seconds
D) 0.44-0.52 seconds
Answer: C) 0.32-0.44 seconds
Explanation: The normal QT interval is 0.32-0.44 seconds
and varies with heart rate. It represents ventricular
depolarization and repolarization, and should be less than
half the R-R interval for a normal QT.
7. On a standard ECG grid, a telemetry technician correctly
identifies that one small horizontal box represents how
much time?
A) 0.01 seconds
B) 0.04 seconds
C) 0.20 seconds
D) 0.50 seconds
, Answer: B) 0.04 seconds
Explanation: One small horizontal box on standard ECG
paper represents 0.04 seconds at a paper speed of 25
mm/s. This is a fundamental measurement for calculating
intervals and heart rate.
8. A nurse is using the 1500 method to calculate heart rate
on a regular rhythm and correctly identifies which constant
is divided by the number of small boxes?
A) 300
B) 1500
C) 3000
D) 10 inches
Answer: B) 1500
Explanation: The 1500 method divides the constant 1500
(representing the number of small boxes in one minute at
standard 25 mm/s paper speed) by the total number of small
boxes between consecutive R waves to yield an accurate
heart rate for regular rhythms.
9. A monitor technician is using the large box method to
calculate heart rate and correctly divides which number by
the large boxes between R waves?
A) Divide 1500 by the number of small boxes
B) Divide 300 by the number of large boxes
C) Multiply the number of R waves in a six-second strip by 10
D) Count the total number of P waves in one minute
Answer: B) Divide 300 by the number of large boxes
Explanation: The large box method divides the constant 300
by the number of large squares separating consecutive R
waves, corresponding to rates of 300, 150, 100, 75, 60, and
50 beats per minute.
