EKG Technician Certification Practice Exam Updated 2026 | Complete
Study Guide with Verified Questions and Detailed Rationales | Cardiac
Anatomy and Physiology, ECG Interpretation, Heart Rhythms and
Dysrhythmias, Lead Placement Techniques, Patient Preparation, Stress
Testing, Holter Monitoring, Artifact Recognition, and Cardiovascular
Monitoring for EKG Certification Exam Success
Question 1: Which lead is considered the most sensitive for detecting inferior wall
myocardial infarction?
A. Lead I
B. Lead aVL
C. Lead II
D. Lead V1
CORRECT ANSWER: C. Lead II
Rationale: Leads II, III, and aVF view the inferior wall of the heart. Among these, Lead II is
often considered the most sensitive for rhythm analysis and detecting inferior ischemia
or infarction because its axis parallels the normal direction of depolarization through
the heart.
Question 2: What is the standard paper speed for a routine 12-lead EKG?
A. 10 mm/sec
B. 25 mm/sec
C. 50 mm/sec
D. 100 mm/sec
CORRECT ANSWER: B. 25 mm/sec
Rationale: The standard international paper speed for diagnostic EKGs is 25 mm/sec. At
this speed, each small horizontal box represents 0.04 seconds, and each large
horizontal box represents 0.20 seconds.
Question 3: Where should the V4 electrode be placed on a male patient?
A. Fourth intercostal space at the right sternal border
B. Fourth intercostal space at the left sternal border
C. Fifth intercostal space at the midclavicular line
D. Fifth intercostal space at the anterior axillary line
CORRECT ANSWER: C. Fifth intercostal space at the midclavicular line
Rationale: The V4 electrode is placed in the fifth intercostal space at the midclavicular
line. This position is critical for accurate precordial lead placement and viewing the
anterior wall of the left ventricle.
Question 4: Which artifact is characterized by a thick, irregular baseline that
obscures the P waves and QRS complexes?
,A. Somatic tremor
B. Wandering baseline
C. AC interference
D. Interrupted baseline
CORRECT ANSWER: A. Somatic tremor
Rationale: Somatic tremor is caused by patient movement, shivering, or Parkinson’s
disease, resulting in a thick, fuzzy, or irregular baseline. It differs from AC interference,
which presents as uniform, fine spikes.
Question 5: What does the P wave represent on an EKG tracing?
A. Ventricular depolarization
B. Ventricular repolarization
C. Atrial depolarization
D. Atrial repolarization
CORRECT ANSWER: C. Atrial depolarization
Rationale: The P wave represents the electrical impulse spreading through the atria,
causing them to contract (depolarize). Atrial repolarization usually occurs during the
QRS complex and is not typically visible.
Question 6: In a standard limb lead configuration, where is the Right Arm (RA)
electrode placed?
A. On the lower right abdomen
B. On the upper right arm, below the shoulder
C. On the right wrist
D. On the right chest near the sternum
CORRECT ANSWER: B. On the upper right arm, below the shoulder
Rationale: Limb electrodes are generally placed on the fleshy parts of the limbs to
reduce artifact. The RA electrode is placed on the upper right arm, avoiding bony
prominences. While wrists are sometimes used, the upper arm is preferred for standard
diagnostic quality to minimize muscle artifact.
Question 7: Which lead is bipolar?
A. aVR
B. aVL
C. Lead I
D. V6
CORRECT ANSWER: C. Lead I
Rationale: Lead I is a bipolar limb lead that measures the potential difference between
the Right Arm (negative pole) and the Left Arm (positive pole). Augmented leads (aVR,
aVL, aVF) and precordial leads (V1-V6) are unipolar.
, Question 8: What is the normal duration of the PR interval in an adult?
A. 0.04 to 0.10 seconds
B. 0.12 to 0.20 seconds
C. 0.20 to 0.30 seconds
D. 0.30 to 0.40 seconds
CORRECT ANSWER: B. 0.12 to 0.20 seconds
Rationale: The normal PR interval ranges from 0.12 to 0.20 seconds (3 to 5 small boxes).
This interval represents the time it takes for the impulse to travel from the SA node
through the AV node to the ventricles.
Question 9: Which condition is most likely to cause a wandering baseline artifact?
A. Patient shivering
B. Poor electrode contact or patient breathing heavily
C. Nearby electrical equipment
D. Broken lead wire
CORRECT ANSWER: B. Poor electrode contact or patient breathing heavily
Rationale: A wandering baseline drifts up and down slowly across the paper. It is
commonly caused by poor electrode adhesion, dried-out gel, or heavy respiratory
movements altering the chest impedance.
Question 10: What is the primary function of the AV node?
A. To initiate the heartbeat
B. To delay the electrical impulse before it reaches the ventricles
C. To conduct impulses rapidly to the Purkinje fibers
D. To repolarize the atria
CORRECT ANSWER: B. To delay the electrical impulse before it reaches the
ventricles
Rationale: The AV node introduces a slight delay (approximately 0.1 seconds) in
conduction. This allows the atria to fully contract and fill the ventricles with blood
before ventricular contraction begins.
Question 11: Which lead views the lateral wall of the left ventricle?
A. V1 and V2
B. V3 and V4
C. Lead I and aVL
D. Lead II, III, and aVF
CORRECT ANSWER: C. Lead I and aVL
Rationale: Leads I and aVL (along with V5 and V6) view the lateral wall of the heart.
Leads II, III, and aVF view the inferior wall, while V1 and V2 view the septal area.
Study Guide with Verified Questions and Detailed Rationales | Cardiac
Anatomy and Physiology, ECG Interpretation, Heart Rhythms and
Dysrhythmias, Lead Placement Techniques, Patient Preparation, Stress
Testing, Holter Monitoring, Artifact Recognition, and Cardiovascular
Monitoring for EKG Certification Exam Success
Question 1: Which lead is considered the most sensitive for detecting inferior wall
myocardial infarction?
A. Lead I
B. Lead aVL
C. Lead II
D. Lead V1
CORRECT ANSWER: C. Lead II
Rationale: Leads II, III, and aVF view the inferior wall of the heart. Among these, Lead II is
often considered the most sensitive for rhythm analysis and detecting inferior ischemia
or infarction because its axis parallels the normal direction of depolarization through
the heart.
Question 2: What is the standard paper speed for a routine 12-lead EKG?
A. 10 mm/sec
B. 25 mm/sec
C. 50 mm/sec
D. 100 mm/sec
CORRECT ANSWER: B. 25 mm/sec
Rationale: The standard international paper speed for diagnostic EKGs is 25 mm/sec. At
this speed, each small horizontal box represents 0.04 seconds, and each large
horizontal box represents 0.20 seconds.
Question 3: Where should the V4 electrode be placed on a male patient?
A. Fourth intercostal space at the right sternal border
B. Fourth intercostal space at the left sternal border
C. Fifth intercostal space at the midclavicular line
D. Fifth intercostal space at the anterior axillary line
CORRECT ANSWER: C. Fifth intercostal space at the midclavicular line
Rationale: The V4 electrode is placed in the fifth intercostal space at the midclavicular
line. This position is critical for accurate precordial lead placement and viewing the
anterior wall of the left ventricle.
Question 4: Which artifact is characterized by a thick, irregular baseline that
obscures the P waves and QRS complexes?
,A. Somatic tremor
B. Wandering baseline
C. AC interference
D. Interrupted baseline
CORRECT ANSWER: A. Somatic tremor
Rationale: Somatic tremor is caused by patient movement, shivering, or Parkinson’s
disease, resulting in a thick, fuzzy, or irregular baseline. It differs from AC interference,
which presents as uniform, fine spikes.
Question 5: What does the P wave represent on an EKG tracing?
A. Ventricular depolarization
B. Ventricular repolarization
C. Atrial depolarization
D. Atrial repolarization
CORRECT ANSWER: C. Atrial depolarization
Rationale: The P wave represents the electrical impulse spreading through the atria,
causing them to contract (depolarize). Atrial repolarization usually occurs during the
QRS complex and is not typically visible.
Question 6: In a standard limb lead configuration, where is the Right Arm (RA)
electrode placed?
A. On the lower right abdomen
B. On the upper right arm, below the shoulder
C. On the right wrist
D. On the right chest near the sternum
CORRECT ANSWER: B. On the upper right arm, below the shoulder
Rationale: Limb electrodes are generally placed on the fleshy parts of the limbs to
reduce artifact. The RA electrode is placed on the upper right arm, avoiding bony
prominences. While wrists are sometimes used, the upper arm is preferred for standard
diagnostic quality to minimize muscle artifact.
Question 7: Which lead is bipolar?
A. aVR
B. aVL
C. Lead I
D. V6
CORRECT ANSWER: C. Lead I
Rationale: Lead I is a bipolar limb lead that measures the potential difference between
the Right Arm (negative pole) and the Left Arm (positive pole). Augmented leads (aVR,
aVL, aVF) and precordial leads (V1-V6) are unipolar.
, Question 8: What is the normal duration of the PR interval in an adult?
A. 0.04 to 0.10 seconds
B. 0.12 to 0.20 seconds
C. 0.20 to 0.30 seconds
D. 0.30 to 0.40 seconds
CORRECT ANSWER: B. 0.12 to 0.20 seconds
Rationale: The normal PR interval ranges from 0.12 to 0.20 seconds (3 to 5 small boxes).
This interval represents the time it takes for the impulse to travel from the SA node
through the AV node to the ventricles.
Question 9: Which condition is most likely to cause a wandering baseline artifact?
A. Patient shivering
B. Poor electrode contact or patient breathing heavily
C. Nearby electrical equipment
D. Broken lead wire
CORRECT ANSWER: B. Poor electrode contact or patient breathing heavily
Rationale: A wandering baseline drifts up and down slowly across the paper. It is
commonly caused by poor electrode adhesion, dried-out gel, or heavy respiratory
movements altering the chest impedance.
Question 10: What is the primary function of the AV node?
A. To initiate the heartbeat
B. To delay the electrical impulse before it reaches the ventricles
C. To conduct impulses rapidly to the Purkinje fibers
D. To repolarize the atria
CORRECT ANSWER: B. To delay the electrical impulse before it reaches the
ventricles
Rationale: The AV node introduces a slight delay (approximately 0.1 seconds) in
conduction. This allows the atria to fully contract and fill the ventricles with blood
before ventricular contraction begins.
Question 11: Which lead views the lateral wall of the left ventricle?
A. V1 and V2
B. V3 and V4
C. Lead I and aVL
D. Lead II, III, and aVF
CORRECT ANSWER: C. Lead I and aVL
Rationale: Leads I and aVL (along with V5 and V6) view the lateral wall of the heart.
Leads II, III, and aVF view the inferior wall, while V1 and V2 view the septal area.
