ECG Workout
Exercises in Arrhythmia Interpretation
8th Edition
Author(s)Jane Huff
,TEST BANK
Table of Contents — ECG Workout: Exercises in Arrhythmia Interpretation, 8th Edition
1. Anatomy and Physiology of the Heart
2. Electrophysiology
3. Waveforms, Complexes, Intervals, and Segments
4. Cardiac Monitors
5. Analyzing a Rhythm Strip
6. Sinus Rhythms
7. Atrial Rhythms
8. Junctional Rhythms and AV Blocks
9. Ventricular Rhythms and Bundle-Branch Block
10. Pacemakers
11. Posttes
Question 1
An ECG shows a regular rhythm at 72 bpm, each QRS complex is
preceded by a uniform upright P wave, PR interval is 0.16
seconds, and QRS duration is 0.08 seconds. Which cardiac
structure is responsible for initiating this impulse?
A. Atrioventricular (AV) node
B. Sinoatrial (SA) node
C. Bundle of His
D. Purkinje fibers
Correct Answer: B
,Rationale:
The ECG shows normal sinus rhythm: regular rate (60–100
bpm), upright P waves before each QRS, normal PR interval,
and narrow QRS. This indicates impulse initiation from the SA
node, the heart’s primary pacemaker.
• A is incorrect: AV node delays conduction but does not
initiate normal rhythm.
• C and D are conduction pathways, not primary
pacemakers.
Source:
ECG Workout: Exercises in Arrhythmia Interpretation, 8th
Edition – Chapter 1
Question 2
An ECG demonstrates a regular rhythm at 55 bpm, upright P
waves before each QRS, and normal PR intervals. Which
physiological property of the SA node explains this slower rate?
A. Automaticity
B. Conductivity
C. Contractility
D. Refractoriness
Correct Answer: A
Rationale:
Automaticity is the ability of pacemaker cells (SA node) to
, initiate impulses. A slower rate (55 bpm) still reflects SA node
firing but at a reduced automatic rate (sinus bradycardia).
• B refers to impulse transmission
• C refers to muscle contraction
• D refers to recovery time
Source:
ECG Workout: Exercises in Arrhythmia Interpretation, 8th
Edition – Chapter 1
Question 3
An ECG rhythm shows regular P waves followed by QRS
complexes. The PR interval is consistently prolonged at 0.24
seconds. Which structure is responsible for this delay?
A. SA node
B. AV node
C. Bundle branches
D. Purkinje fibers
Correct Answer: B
Rationale:
The AV node slows conduction, producing the PR interval. A
prolonged PR interval indicates delayed conduction through the
AV node (first-degree AV block).
• A initiates impulse
Exercises in Arrhythmia Interpretation
8th Edition
Author(s)Jane Huff
,TEST BANK
Table of Contents — ECG Workout: Exercises in Arrhythmia Interpretation, 8th Edition
1. Anatomy and Physiology of the Heart
2. Electrophysiology
3. Waveforms, Complexes, Intervals, and Segments
4. Cardiac Monitors
5. Analyzing a Rhythm Strip
6. Sinus Rhythms
7. Atrial Rhythms
8. Junctional Rhythms and AV Blocks
9. Ventricular Rhythms and Bundle-Branch Block
10. Pacemakers
11. Posttes
Question 1
An ECG shows a regular rhythm at 72 bpm, each QRS complex is
preceded by a uniform upright P wave, PR interval is 0.16
seconds, and QRS duration is 0.08 seconds. Which cardiac
structure is responsible for initiating this impulse?
A. Atrioventricular (AV) node
B. Sinoatrial (SA) node
C. Bundle of His
D. Purkinje fibers
Correct Answer: B
,Rationale:
The ECG shows normal sinus rhythm: regular rate (60–100
bpm), upright P waves before each QRS, normal PR interval,
and narrow QRS. This indicates impulse initiation from the SA
node, the heart’s primary pacemaker.
• A is incorrect: AV node delays conduction but does not
initiate normal rhythm.
• C and D are conduction pathways, not primary
pacemakers.
Source:
ECG Workout: Exercises in Arrhythmia Interpretation, 8th
Edition – Chapter 1
Question 2
An ECG demonstrates a regular rhythm at 55 bpm, upright P
waves before each QRS, and normal PR intervals. Which
physiological property of the SA node explains this slower rate?
A. Automaticity
B. Conductivity
C. Contractility
D. Refractoriness
Correct Answer: A
Rationale:
Automaticity is the ability of pacemaker cells (SA node) to
, initiate impulses. A slower rate (55 bpm) still reflects SA node
firing but at a reduced automatic rate (sinus bradycardia).
• B refers to impulse transmission
• C refers to muscle contraction
• D refers to recovery time
Source:
ECG Workout: Exercises in Arrhythmia Interpretation, 8th
Edition – Chapter 1
Question 3
An ECG rhythm shows regular P waves followed by QRS
complexes. The PR interval is consistently prolonged at 0.24
seconds. Which structure is responsible for this delay?
A. SA node
B. AV node
C. Bundle branches
D. Purkinje fibers
Correct Answer: B
Rationale:
The AV node slows conduction, producing the PR interval. A
prolonged PR interval indicates delayed conduction through the
AV node (first-degree AV block).
• A initiates impulse
