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, the PR interval
measures 0.16 seconds, and QRS duration is 0.08 seconds.
Which structure is primarily responsible for initiating this
rhythm?
A. Atrioventricular (AV) node
B. Sinoatrial (SA) node
,C. Bundle of His
D. Purkinje fibers
Correct Answer: B
Rationale:
The ECG demonstrates a normal sinus rhythm: regular rate (60–
100 bpm), upright and consistent P waves before each QRS,
normal PR interval (0.12–0.20 sec), and narrow QRS (<0.12 sec).
This indicates impulse initiation from the SA node.
• A is incorrect: AV node delays conduction, does not initiate
normal rhythm.
• C and D are conduction pathways, not primary pacemakers
under normal conditions.
Source:
ECG Workout: Exercises in Arrhythmia Interpretation, 8th
Edition – Chapter 1
Question 2
An ECG tracing shows a regular rhythm at 60 bpm. P waves are
present but inverted before each QRS, and PR interval is short
(0.10 seconds). QRS complexes are narrow. Which part of the
conduction system is likely generating this rhythm?
A. SA node
B. AV junction
C. Atrial myocardium
D. Bundle branches
, Correct Answer: B
Rationale:
Inverted P waves with a short PR interval indicate impulse
origin near or within the AV junction, causing retrograde atrial
depolarization. Narrow QRS confirms normal ventricular
conduction.
• A would produce upright P waves.
• C would produce abnormal P morphology but not typical
inverted pattern with short PR.
• D does not initiate rhythm.
Source:
ECG Workout: Exercises in Arrhythmia Interpretation, 8th
Edition – Chapter 1
Question 3
A patient’s ECG shows no visible P waves, a slow regular rhythm
at 38 bpm, and wide QRS complexes (0.14 seconds). Which
structure is most likely pacing the heart?
A. SA node
B. AV node
C. Ventricles (Purkinje system)
D. Atria
Correct Answer: C
Rationale:
Absent P waves, slow rate (<40 bpm), and wide QRS indicate a
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, the PR interval
measures 0.16 seconds, and QRS duration is 0.08 seconds.
Which structure is primarily responsible for initiating this
rhythm?
A. Atrioventricular (AV) node
B. Sinoatrial (SA) node
,C. Bundle of His
D. Purkinje fibers
Correct Answer: B
Rationale:
The ECG demonstrates a normal sinus rhythm: regular rate (60–
100 bpm), upright and consistent P waves before each QRS,
normal PR interval (0.12–0.20 sec), and narrow QRS (<0.12 sec).
This indicates impulse initiation from the SA node.
• A is incorrect: AV node delays conduction, does not initiate
normal rhythm.
• C and D are conduction pathways, not primary pacemakers
under normal conditions.
Source:
ECG Workout: Exercises in Arrhythmia Interpretation, 8th
Edition – Chapter 1
Question 2
An ECG tracing shows a regular rhythm at 60 bpm. P waves are
present but inverted before each QRS, and PR interval is short
(0.10 seconds). QRS complexes are narrow. Which part of the
conduction system is likely generating this rhythm?
A. SA node
B. AV junction
C. Atrial myocardium
D. Bundle branches
, Correct Answer: B
Rationale:
Inverted P waves with a short PR interval indicate impulse
origin near or within the AV junction, causing retrograde atrial
depolarization. Narrow QRS confirms normal ventricular
conduction.
• A would produce upright P waves.
• C would produce abnormal P morphology but not typical
inverted pattern with short PR.
• D does not initiate rhythm.
Source:
ECG Workout: Exercises in Arrhythmia Interpretation, 8th
Edition – Chapter 1
Question 3
A patient’s ECG shows no visible P waves, a slow regular rhythm
at 38 bpm, and wide QRS complexes (0.14 seconds). Which
structure is most likely pacing the heart?
A. SA node
B. AV node
C. Ventricles (Purkinje system)
D. Atria
Correct Answer: C
Rationale:
Absent P waves, slow rate (<40 bpm), and wide QRS indicate a
