PRACTICE QUESTIONS & GRADED A+
SOLUTION BANK
This comprehensive practice exam bundle delivers verified multiple-
choice questions with precise answers and detailed rationales tailored
for rapid EKG and ECG rhythm mastery. It covers vital clinical
competencies including core interval calculations, complex heart block
protocols, lethal arrhythmia interventions, and pacemaker
troubleshooting mechanics. Designed strictly to match the evaluation
criteria of modern nursing certifications, this test bank serves as an
indispensable resource for achieving top-tier passing grades.
1. What is the primary pacemaker of the heart,
normally firing at a rate of 60 to 100 beats per minute?
A) Atrioventricular (AV) node
B) Purkinje fibers
C) Sinoatrial (SA) node
D) Bundle of His
Answer: C) Sinoatrial (SA) node
Rationale: The SA node is located in the upper right
atrium and serves as the heart's primary pacemaker due
to its rapid intrinsic firing rate.
2. On standard EKG graph paper, a small box represents
how much time?
,A) 0.20 seconds
B) 0.04 seconds
C) 0.12 seconds
D) 0.40 seconds
Answer: B) 0.04 seconds
Rationale: Each small 1mm box on EKG paper
represents 0.04 seconds horizontally. Five small boxes
equal one large box, which represents 0.20 seconds.
3. Which of the following PR interval measurements
falls within the normal physiological range?
A) 0.16 seconds
B) 0.08 seconds
C) 0.24 seconds
D) 0.30 seconds
Answer: A) 0.16 seconds
Rationale: A normal PR interval ranges between 0.12
and 0.20 seconds (3 to 5 small boxes). Anything over
0.20 seconds indicates a first-degree AV block.
4. A standard normal QRS complex should measure less
than how many seconds?
A) 0.20 seconds
B) 0.16 seconds
C) 0.12 seconds
,D) 0.04 seconds
Answer: C) 0.12 seconds
Rationale: A normal QRS duration is narrow, measuring
less than 0.12 seconds (under 3 small boxes), indicating
rapid intraventricular conduction.
5. What does the P wave on an EKG trace represent?
A) Ventricular depolarization
B) Atrial repolarization
C) Atrial depolarization
D) Ventricular repolarization
Answer: C) Atrial depolarization
Rationale: The P wave represents the electrical impulse
spreading across the atria, causing them to contract.
6. What does the T wave on an EKG trace represent?
A) Atrial contraction
B) Ventricular repolarization
C) Ventricular contraction
D) Atrial repolarization
Answer: B) Ventricular repolarization
Rationale: The T wave represents the electrical recovery
or resting phase of the ventricles.
, 7. An EKG rhythm shows regular P-P intervals, regular R-
R intervals, a heart rate of 42 bpm, and a normal PR
interval. What is this rhythm?
A) Normal Sinus Rhythm
B) Sinus Bradycardia
C) Sinus Tachycardia
D) First-Degree AV Block
Answer: B) Sinus Bradycardia
Rationale: Sinus bradycardia meets all the criteria of a
normal sinus rhythm except that the firing rate is less
than 60 beats per minute.
8. An EKG rhythm shows regular upright P waves, a
regular ventricular response, a normal QRS complex,
and a heart rate of 125 bpm. What is this rhythm?
A) Atrial Flutter
B) Sinus Bradycardia
C) Sinus Tachycardia
D) Ventricular Tachycardia
Answer: C) Sinus Tachycardia
Rationale: Sinus tachycardia originates in the SA node
with a regular rhythm but has an accelerated firing rate
between 101 and 150 bpm.