CARDIAC HEALTHSTREAM TELEMETRY EXAM (2025/2026) COMPREHENSIVE
QUESTIONS AND VERIFIED ANSWERS ( DETAILED & ELABORATED) ACTUAL EXAM
2025/2026 TEST!!
Question 1
Which structure is considered the primary pacemaker of the heart, normally firing at a rate of 60
to 100 beats per minute?
A) AV Node
B) Bundle of His
C) SA Node
D) Purkinje Fibers
E) Internodal Pathways
Correct Answer: C) SA Node
Rationale: The Sinoatrial (SA) node is located in the right atrium and is the heart's natural
pacemaker because it has the highest inherent rate of automaticity. It initiates the electrical
impulse that leads to atrial depolarization. If the SA node fails, backup pacemakers like the
AV node or ventricular sites take over at slower rates.
Question 2
On standard EKG telemetry paper, what is the time value represented by one small horizontal
box?
A) 0.20 seconds
B) 0.12 seconds
C) 0.04 seconds
D) 0.40 seconds
E) 1.00 second
Correct Answer: C) 0.04 seconds
Rationale: EKG paper is standardized to move at a speed of 25mm/sec. One small block
(1mm) represents 0.04 seconds. Five small blocks make up one large block, which
represents 0.20 seconds (0.04 x 5 = 0.20). Understanding these measurements is vital for
calculating heart rate and interval durations like the PR interval and QRS width.
, 2
Question 3
What is the inherent firing rate of the Atrioventricular (AV) node when it acts as the heart's
backup pacemaker?
A) 60-100 bpm
B) 20-40 bpm
C) 40-60 bpm
) 14-20 bpm
E) 100-150 bpm
Correct Answer: C) 40-60 bpm
Rationale: The AV node serves as the secondary pacemaker. If the SA node is damaged or its
impulse is blocked, the AV node will begin to fire at its native rate of 40-60 bpm. This is
known as a junctional rhythm, which provides a safety mechanism to maintain cardiac
output when the primary pacemaker fails.
Question 4
Which component of the conduction system represents the last "escape" pacemaker site, firing at
a rate of approximately 20 to 40 beats per minute?
A) SA Node
B) Internodal Pathways
C) Bundle of His
D) Purkinje Fibers
E) Left Bundle Branch
Correct Answer: D) Purkinje Fibers
Rationale: The Purkinje fibers make up the terminal end of the conduction system within
the ventricular myocardium. They have the slowest inherent rate of automaticity (20-40
bpm). If both the SA and AV nodes fail to fire, the Purkinje system acts as a "life-saving"
escape rhythm, though the resulting cardiac output is usually insufficient for long-term
survival.
Question 5
The PR Interval (PRI) measures the time it takes for an electrical impulse to travel from the atria
, 3
through the AV node. What is the normal duration for a PRI?
A) 0.04 - 0.10 seconds
B) 0.08 - 0.12 seconds
C) 0.12 - 0.20 seconds
D) 0.35 - 0.43 seconds
E) 0.20 - 0.40 seconds
Correct Answer: C) 0.12 - 0.20 seconds
Rationale: A normal PR interval ranges from 0.12 to 0.20 seconds (3 to 5 small boxes). It
represents the time from the onset of atrial depolarization to the onset of ventricular
depolarization. A PRI greater than 0.20 seconds indicates a delay in conduction through the
AV node, which is classified as a first-degree AV block.
Question 6
The QRS complex represents ventricular depolarization. What is the standard measurement for a
normal QRS complex width?
A) < 0.04 seconds
B) 0.12 - 0.20 seconds
C) 0.08 - 0.12 seconds
D) 0.20 - 0.30 seconds
E) > 0.12 seconds
Correct Answer: C) 0.08 - 0.12 seconds
Rationale: A normal QRS complex should be narrow, typically between 0.08 and 0.12
seconds (2 to 3 small boxes). A wide QRS (>0.12s) suggests that the electrical impulse is
traveling slowly through the ventricles, often due to a bundle branch block or because the
impulse originated in the ventricles rather than the supraventricular conduction system.
Question 7
In a standard EKG tracing, what does the P-wave represent?
A) Ventricular contraction
B) Atrial repolarization
C) Atrial depolarization
, 4
D) Ventricular repolarization
E) Delay at the AV node
Correct Answer: C) Atrial depolarization
Rationale: The P-wave is the first deflection on the EKG. It represents the electrical
activation (depolarization) of the right and left atria. Under normal conditions, the SA node
fires, the atria depolarize (P-wave), and then the atria physically contract to pump blood
into the ventricles.
Question 8
When using the 6-second strip method to interpret a heart rate, a nurse counts the number of R-
waves in a 6-second interval and multiplies by:
A) 5
B) 10
C) 20
D) 15
E) 60
Correct Answer: B) 10
Rationale: The 6-second method is the fastest way to estimate heart rate, especially for
irregular rhythms. By counting the number of QRS complexes (R-waves) in a 6-second
segment of the strip and multiplying by 10, you obtain the beats per minute (6 seconds x 10
= 60 seconds or 1 minute).
Question 9
A telemetry strip shows a regular rhythm, a heart rate of 72 bpm, a PRI of 0.16 seconds, and a
QRS of 0.08 seconds. Every P-wave is followed by a QRS. This is classified as:
A) Sinus Bradycardia
B) Sinus Tachycardia
C) Normal Sinus Rhythm (NSR)
D) Atrial Flutter
E) First-Degree AV Block
QUESTIONS AND VERIFIED ANSWERS ( DETAILED & ELABORATED) ACTUAL EXAM
2025/2026 TEST!!
Question 1
Which structure is considered the primary pacemaker of the heart, normally firing at a rate of 60
to 100 beats per minute?
A) AV Node
B) Bundle of His
C) SA Node
D) Purkinje Fibers
E) Internodal Pathways
Correct Answer: C) SA Node
Rationale: The Sinoatrial (SA) node is located in the right atrium and is the heart's natural
pacemaker because it has the highest inherent rate of automaticity. It initiates the electrical
impulse that leads to atrial depolarization. If the SA node fails, backup pacemakers like the
AV node or ventricular sites take over at slower rates.
Question 2
On standard EKG telemetry paper, what is the time value represented by one small horizontal
box?
A) 0.20 seconds
B) 0.12 seconds
C) 0.04 seconds
D) 0.40 seconds
E) 1.00 second
Correct Answer: C) 0.04 seconds
Rationale: EKG paper is standardized to move at a speed of 25mm/sec. One small block
(1mm) represents 0.04 seconds. Five small blocks make up one large block, which
represents 0.20 seconds (0.04 x 5 = 0.20). Understanding these measurements is vital for
calculating heart rate and interval durations like the PR interval and QRS width.
, 2
Question 3
What is the inherent firing rate of the Atrioventricular (AV) node when it acts as the heart's
backup pacemaker?
A) 60-100 bpm
B) 20-40 bpm
C) 40-60 bpm
) 14-20 bpm
E) 100-150 bpm
Correct Answer: C) 40-60 bpm
Rationale: The AV node serves as the secondary pacemaker. If the SA node is damaged or its
impulse is blocked, the AV node will begin to fire at its native rate of 40-60 bpm. This is
known as a junctional rhythm, which provides a safety mechanism to maintain cardiac
output when the primary pacemaker fails.
Question 4
Which component of the conduction system represents the last "escape" pacemaker site, firing at
a rate of approximately 20 to 40 beats per minute?
A) SA Node
B) Internodal Pathways
C) Bundle of His
D) Purkinje Fibers
E) Left Bundle Branch
Correct Answer: D) Purkinje Fibers
Rationale: The Purkinje fibers make up the terminal end of the conduction system within
the ventricular myocardium. They have the slowest inherent rate of automaticity (20-40
bpm). If both the SA and AV nodes fail to fire, the Purkinje system acts as a "life-saving"
escape rhythm, though the resulting cardiac output is usually insufficient for long-term
survival.
Question 5
The PR Interval (PRI) measures the time it takes for an electrical impulse to travel from the atria
, 3
through the AV node. What is the normal duration for a PRI?
A) 0.04 - 0.10 seconds
B) 0.08 - 0.12 seconds
C) 0.12 - 0.20 seconds
D) 0.35 - 0.43 seconds
E) 0.20 - 0.40 seconds
Correct Answer: C) 0.12 - 0.20 seconds
Rationale: A normal PR interval ranges from 0.12 to 0.20 seconds (3 to 5 small boxes). It
represents the time from the onset of atrial depolarization to the onset of ventricular
depolarization. A PRI greater than 0.20 seconds indicates a delay in conduction through the
AV node, which is classified as a first-degree AV block.
Question 6
The QRS complex represents ventricular depolarization. What is the standard measurement for a
normal QRS complex width?
A) < 0.04 seconds
B) 0.12 - 0.20 seconds
C) 0.08 - 0.12 seconds
D) 0.20 - 0.30 seconds
E) > 0.12 seconds
Correct Answer: C) 0.08 - 0.12 seconds
Rationale: A normal QRS complex should be narrow, typically between 0.08 and 0.12
seconds (2 to 3 small boxes). A wide QRS (>0.12s) suggests that the electrical impulse is
traveling slowly through the ventricles, often due to a bundle branch block or because the
impulse originated in the ventricles rather than the supraventricular conduction system.
Question 7
In a standard EKG tracing, what does the P-wave represent?
A) Ventricular contraction
B) Atrial repolarization
C) Atrial depolarization
, 4
D) Ventricular repolarization
E) Delay at the AV node
Correct Answer: C) Atrial depolarization
Rationale: The P-wave is the first deflection on the EKG. It represents the electrical
activation (depolarization) of the right and left atria. Under normal conditions, the SA node
fires, the atria depolarize (P-wave), and then the atria physically contract to pump blood
into the ventricles.
Question 8
When using the 6-second strip method to interpret a heart rate, a nurse counts the number of R-
waves in a 6-second interval and multiplies by:
A) 5
B) 10
C) 20
D) 15
E) 60
Correct Answer: B) 10
Rationale: The 6-second method is the fastest way to estimate heart rate, especially for
irregular rhythms. By counting the number of QRS complexes (R-waves) in a 6-second
segment of the strip and multiplying by 10, you obtain the beats per minute (6 seconds x 10
= 60 seconds or 1 minute).
Question 9
A telemetry strip shows a regular rhythm, a heart rate of 72 bpm, a PRI of 0.16 seconds, and a
QRS of 0.08 seconds. Every P-wave is followed by a QRS. This is classified as:
A) Sinus Bradycardia
B) Sinus Tachycardia
C) Normal Sinus Rhythm (NSR)
D) Atrial Flutter
E) First-Degree AV Block
