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EKGs FOR THE NURSE PRACTITIONER AND
PHYSICIAN ASSISSTANT Final Exam Newest Exam
Preparation With Complete Questions And Correct
Answers With Rationales | Already Graded A+||Brand
New Version!!
1. A 12-lead EKG records the electrical activity of the heart from how
many different spatial orientations?
A) 6
B) 10
C) 12
D) 18
Answer: C) 12
Explanation: A standard 12-lead EKG records electrical activity from 12
different spatial leads, consisting of 6 limb leads (I, II, III, aVR, aVL, aVF)
and 6 precordial leads (V1-V6). The term "lead" in electrocardiography
refers to a specific spatial orientation or a "view" of the heart's
electrical activity, not a physical wire. These 12 leads provide a
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comprehensive three-dimensional assessment of cardiac depolarization
and repolarization, which is essential for accurate interpretation.
2. Which of the following leads is considered a bipolar lead?
A) aVR
B) aVL
C) aVF
D) Lead II
Answer: D) Lead II
Explanation: Bipolar leads measure the voltage difference between two
points (electrodes). Leads I, II, and III are the standard bipolar limb
leads. Lead II, in particular, records the potential difference between the
right arm (negative electrode) and the left leg (positive electrode). In
contrast, the augmented leads (aVR, aVL, aVF) are unipolar leads,
meaning they measure the electrical potential at a single point relative
to a "zero" reference point, not between two discrete limb electrodes.
3. The P wave on a normal EKG represents:
A) Ventricular depolarization
B) Atrial depolarization
C) Ventricular repolarization
D) The AV nodal delay
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Answer: B) Atrial depolarization
Explanation: The P wave is the first deflection on the EKG and
represents the spread of the electrical impulse through the atria,
resulting in atrial depolarization. This is followed by atrial contraction,
though contraction is not directly represented on the EKG. Ventricular
depolarization is represented by the QRS complex, and ventricular
repolarization by the T wave. The PR segment, not the P wave,
corresponds to the AV nodal delay.
4. The normal duration of the PR interval is:
A) 0.04 to 0.10 seconds
B) 0.12 to 0.20 seconds
C) 0.20 to 0.30 seconds
D) 0.36 to 0.44 seconds
Answer: B) 0.12 to 0.20 seconds
Explanation: The PR interval is measured from the beginning of the P
wave to the beginning of the QRS complex and represents the time from
the onset of atrial depolarization to the onset of ventricular
depolarization. This includes the conduction time through the atria, the
AV node, and the His-Purkinje system. A normal PR interval ranges from
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120 to 200 milliseconds (0.12-0.20 seconds) at a normal heart rate. A
prolonged PR interval suggests a first-degree AV block.
5. The QRS complex represents:
A) Atrial depolarization and repolarization
B) Ventricular depolarization
C) Ventricular repolarization
D) Atrial repolarization
Answer: B) Ventricular depolarization
Explanation: The QRS complex is a rapid, sharp deflection that
represents the depolarization of the ventricular myocardium. This is the
primary electrical event that initiates ventricular contraction. The QRS
complex is typically narrow (less than 0.12 seconds) because conduction
through the His-Purkinje system is rapid. A wide QRS complex suggests
an abnormality in ventricular conduction, such as a bundle branch block
or ventricular ectopy.
6. The normal duration of the QRS complex is:
A) Less than 0.06 seconds
B) Less than 0.12 seconds
C) Less than 0.20 seconds
D) Less than 0.30 seconds
EKGs FOR THE NURSE PRACTITIONER AND
PHYSICIAN ASSISSTANT Final Exam Newest Exam
Preparation With Complete Questions And Correct
Answers With Rationales | Already Graded A+||Brand
New Version!!
1. A 12-lead EKG records the electrical activity of the heart from how
many different spatial orientations?
A) 6
B) 10
C) 12
D) 18
Answer: C) 12
Explanation: A standard 12-lead EKG records electrical activity from 12
different spatial leads, consisting of 6 limb leads (I, II, III, aVR, aVL, aVF)
and 6 precordial leads (V1-V6). The term "lead" in electrocardiography
refers to a specific spatial orientation or a "view" of the heart's
electrical activity, not a physical wire. These 12 leads provide a
,2|Page
comprehensive three-dimensional assessment of cardiac depolarization
and repolarization, which is essential for accurate interpretation.
2. Which of the following leads is considered a bipolar lead?
A) aVR
B) aVL
C) aVF
D) Lead II
Answer: D) Lead II
Explanation: Bipolar leads measure the voltage difference between two
points (electrodes). Leads I, II, and III are the standard bipolar limb
leads. Lead II, in particular, records the potential difference between the
right arm (negative electrode) and the left leg (positive electrode). In
contrast, the augmented leads (aVR, aVL, aVF) are unipolar leads,
meaning they measure the electrical potential at a single point relative
to a "zero" reference point, not between two discrete limb electrodes.
3. The P wave on a normal EKG represents:
A) Ventricular depolarization
B) Atrial depolarization
C) Ventricular repolarization
D) The AV nodal delay
,3|Page
Answer: B) Atrial depolarization
Explanation: The P wave is the first deflection on the EKG and
represents the spread of the electrical impulse through the atria,
resulting in atrial depolarization. This is followed by atrial contraction,
though contraction is not directly represented on the EKG. Ventricular
depolarization is represented by the QRS complex, and ventricular
repolarization by the T wave. The PR segment, not the P wave,
corresponds to the AV nodal delay.
4. The normal duration of the PR interval is:
A) 0.04 to 0.10 seconds
B) 0.12 to 0.20 seconds
C) 0.20 to 0.30 seconds
D) 0.36 to 0.44 seconds
Answer: B) 0.12 to 0.20 seconds
Explanation: The PR interval is measured from the beginning of the P
wave to the beginning of the QRS complex and represents the time from
the onset of atrial depolarization to the onset of ventricular
depolarization. This includes the conduction time through the atria, the
AV node, and the His-Purkinje system. A normal PR interval ranges from
, 4|Page
120 to 200 milliseconds (0.12-0.20 seconds) at a normal heart rate. A
prolonged PR interval suggests a first-degree AV block.
5. The QRS complex represents:
A) Atrial depolarization and repolarization
B) Ventricular depolarization
C) Ventricular repolarization
D) Atrial repolarization
Answer: B) Ventricular depolarization
Explanation: The QRS complex is a rapid, sharp deflection that
represents the depolarization of the ventricular myocardium. This is the
primary electrical event that initiates ventricular contraction. The QRS
complex is typically narrow (less than 0.12 seconds) because conduction
through the His-Purkinje system is rapid. A wide QRS complex suggests
an abnormality in ventricular conduction, such as a bundle branch block
or ventricular ectopy.
6. The normal duration of the QRS complex is:
A) Less than 0.06 seconds
B) Less than 0.12 seconds
C) Less than 0.20 seconds
D) Less than 0.30 seconds
