41. Which cardiac structure typically generates impulses at a rate of 60-100 beats per
minute, acting as the heart's primary pacemaker?
A. AV node
B. Bundle of His
C. Purkinje fibers
D. SA node
Answer: D
Rationale: The sinoatrial (SA) node, located at the top of the right atrium, is the primary
pacemaker of the heart and typically generates impulses at a rate of 60-100 beats per
minute, setting the rhythm for the rest of the heart.
42. Which dysrhythmia is characterized by a regular rhythm with a heart rate less than
60 beats per minute?
A. Sinus tachycardia
B. Sinus bradycardia
C. Atrial flutter
D. Ventricular fibrillation
Answer: B
Rationale: Sinus bradycardia is a regular rhythm originating from the SA node with a
slower rate of less than 60 beats per minute, often seen in athletes or due to increased
vagal tone.
43. In which condition might atropine be administered to increase the heart rate?
A. Atrial fibrillation
B. Sinus bradycardia with symptoms
C. Ventricular tachycardia
D. Atrial flutter
Answer: B
Rationale: Atropine is used to increase the heart rate in cases of symptomatic sinus
bradycardia, as it blocks vagal stimulation, allowing for a faster heart rate. It is not
indicated for atrial fibrillation, ventricular tachycardia, or atrial flutter.
44. What does the T wave on an ECG represent?
A. Atrial depolarization
B. Ventricular depolarization
This study source was downloaded by 1244232 from cliffsnotes.com on 08-06-2025 06:10:34 GMT -05:00
https://www.cliffsnotes.com//study-notes/23752476
, C. Ventricular repolarization
D. Atrial repolarization
Answer: C
Rationale: The T wave represents ventricular repolarization, the phase when the
ventricles recover after contraction. Atrial repolarization is typically masked by the QRS
complex.
45. Which of the following treatments is appropriate for a patient with atrial fibrillation
and a rapid ventricular response?
A. Atropine
B. Calcium channel blockers (e.g., diltiazem)
C. Epinephrine
D. Defibrillation
Answer: B
Rationale: Calcium channel blockers are commonly used to slow the ventricular rate in
patients with atrial fibrillation with rapid ventricular response. Atropine and epinephrine
would not be effective for rate control in atrial fibrillation, and defibrillation is reserved
for life-threatening arrhythmias like ventricular fibrillation.
46. Which condition is associated with a saw-tooth pattern on the ECG due to rapid
atrial depolarizations?
A. Atrial fibrillation
B. Atrial flutter
C. Ventricular fibrillation
D. First-degree AV block
Answer: B
Rationale: Atrial flutter is characterized by a saw-tooth pattern on the ECG, resulting
from rapid atrial depolarizations at a rate of 250-350 beats per minute. This pattern is
unique to atrial flutter and helps differentiate it from atrial fibrillation.
47. What is the primary treatment goal for a patient experiencing ventricular
fibrillation?
A. Administration of beta-blockers
B. Immediate defibrillation and CPR
C. Atropine administration
D. Placement of a permanent pacemaker
This study source was downloaded by 1244232 from cliffsnotes.com on 08-06-2025 06:10:34 GMT -05:00
https://www.cliffsnotes.com//study-notes/23752476
minute, acting as the heart's primary pacemaker?
A. AV node
B. Bundle of His
C. Purkinje fibers
D. SA node
Answer: D
Rationale: The sinoatrial (SA) node, located at the top of the right atrium, is the primary
pacemaker of the heart and typically generates impulses at a rate of 60-100 beats per
minute, setting the rhythm for the rest of the heart.
42. Which dysrhythmia is characterized by a regular rhythm with a heart rate less than
60 beats per minute?
A. Sinus tachycardia
B. Sinus bradycardia
C. Atrial flutter
D. Ventricular fibrillation
Answer: B
Rationale: Sinus bradycardia is a regular rhythm originating from the SA node with a
slower rate of less than 60 beats per minute, often seen in athletes or due to increased
vagal tone.
43. In which condition might atropine be administered to increase the heart rate?
A. Atrial fibrillation
B. Sinus bradycardia with symptoms
C. Ventricular tachycardia
D. Atrial flutter
Answer: B
Rationale: Atropine is used to increase the heart rate in cases of symptomatic sinus
bradycardia, as it blocks vagal stimulation, allowing for a faster heart rate. It is not
indicated for atrial fibrillation, ventricular tachycardia, or atrial flutter.
44. What does the T wave on an ECG represent?
A. Atrial depolarization
B. Ventricular depolarization
This study source was downloaded by 1244232 from cliffsnotes.com on 08-06-2025 06:10:34 GMT -05:00
https://www.cliffsnotes.com//study-notes/23752476
, C. Ventricular repolarization
D. Atrial repolarization
Answer: C
Rationale: The T wave represents ventricular repolarization, the phase when the
ventricles recover after contraction. Atrial repolarization is typically masked by the QRS
complex.
45. Which of the following treatments is appropriate for a patient with atrial fibrillation
and a rapid ventricular response?
A. Atropine
B. Calcium channel blockers (e.g., diltiazem)
C. Epinephrine
D. Defibrillation
Answer: B
Rationale: Calcium channel blockers are commonly used to slow the ventricular rate in
patients with atrial fibrillation with rapid ventricular response. Atropine and epinephrine
would not be effective for rate control in atrial fibrillation, and defibrillation is reserved
for life-threatening arrhythmias like ventricular fibrillation.
46. Which condition is associated with a saw-tooth pattern on the ECG due to rapid
atrial depolarizations?
A. Atrial fibrillation
B. Atrial flutter
C. Ventricular fibrillation
D. First-degree AV block
Answer: B
Rationale: Atrial flutter is characterized by a saw-tooth pattern on the ECG, resulting
from rapid atrial depolarizations at a rate of 250-350 beats per minute. This pattern is
unique to atrial flutter and helps differentiate it from atrial fibrillation.
47. What is the primary treatment goal for a patient experiencing ventricular
fibrillation?
A. Administration of beta-blockers
B. Immediate defibrillation and CPR
C. Atropine administration
D. Placement of a permanent pacemaker
This study source was downloaded by 1244232 from cliffsnotes.com on 08-06-2025 06:10:34 GMT -05:00
https://www.cliffsnotes.com//study-notes/23752476
