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
A patient’s ECG shows a regular rhythm at 72 bpm, with upright
P waves before each QRS complex and consistent PR intervals.
Which structure is responsible for initiating this normal
impulse?
A. Atrioventricular (AV) node
B. Sinoatrial (SA) node
C. Bundle of His
D. Purkinje fibers
Correct Answer: B
,Rationale:
The SA node is the primary pacemaker of the heart, initiating
impulses that produce normal sinus rhythm. The presence of
upright P waves before each QRS indicates atrial depolarization
originating from the SA node.
• AV node delays conduction but does not initiate normal
sinus rhythm
• Bundle of His and Purkinje fibers conduct impulses, not
initiate them
Source:
ECG Workout: Exercises in Arrhythmia Interpretation, 8th
Edition – Chapter 1
Question 2
An ECG rhythm strip shows delayed PR intervals (>0.20
seconds) with all P waves conducted. Which cardiac structure is
responsible for this delay?
A. SA node
B. AV node
C. Right bundle branch
D. Left ventricle
Correct Answer: B
Rationale:
The AV node slows impulse conduction, reflected as the PR
, interval. A prolonged PR interval indicates delayed conduction
through the AV node.
• SA node initiates impulses
• Bundle branches affect QRS, not PR interval
• Ventricles generate QRS complexes
Source:
ECG Workout: Exercises in Arrhythmia Interpretation, 8th
Edition – Chapter 1
Question 3
A patient’s ECG shows absence of P waves with a slow
ventricular rate of 40 bpm and wide QRS complexes. Which
part of the conduction system is likely pacing the heart?
A. SA node
B. AV node
C. Purkinje fibers
D. Atria
Correct Answer: C
Rationale:
Wide QRS complexes and slow rate suggest ventricular pacing
from Purkinje fibers. These act as a backup pacemaker when
higher pacemakers fail.
• SA and AV nodes produce narrower QRS
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
A patient’s ECG shows a regular rhythm at 72 bpm, with upright
P waves before each QRS complex and consistent PR intervals.
Which structure is responsible for initiating this normal
impulse?
A. Atrioventricular (AV) node
B. Sinoatrial (SA) node
C. Bundle of His
D. Purkinje fibers
Correct Answer: B
,Rationale:
The SA node is the primary pacemaker of the heart, initiating
impulses that produce normal sinus rhythm. The presence of
upright P waves before each QRS indicates atrial depolarization
originating from the SA node.
• AV node delays conduction but does not initiate normal
sinus rhythm
• Bundle of His and Purkinje fibers conduct impulses, not
initiate them
Source:
ECG Workout: Exercises in Arrhythmia Interpretation, 8th
Edition – Chapter 1
Question 2
An ECG rhythm strip shows delayed PR intervals (>0.20
seconds) with all P waves conducted. Which cardiac structure is
responsible for this delay?
A. SA node
B. AV node
C. Right bundle branch
D. Left ventricle
Correct Answer: B
Rationale:
The AV node slows impulse conduction, reflected as the PR
, interval. A prolonged PR interval indicates delayed conduction
through the AV node.
• SA node initiates impulses
• Bundle branches affect QRS, not PR interval
• Ventricles generate QRS complexes
Source:
ECG Workout: Exercises in Arrhythmia Interpretation, 8th
Edition – Chapter 1
Question 3
A patient’s ECG shows absence of P waves with a slow
ventricular rate of 40 bpm and wide QRS complexes. Which
part of the conduction system is likely pacing the heart?
A. SA node
B. AV node
C. Purkinje fibers
D. Atria
Correct Answer: C
Rationale:
Wide QRS complexes and slow rate suggest ventricular pacing
from Purkinje fibers. These act as a backup pacemaker when
higher pacemakers fail.
• SA and AV nodes produce narrower QRS
