CET Practice Test – Electrocardiography, Cardiac
Anatomy, Lead Placement, Rhythm Interpretation
and Patient Care
1. A technician is performing a 12-lead EKG and notices a jagged, irregular baseline. The
patient is shivering due to a cold exam room. Which type of artifact is this?
A. AC Interference
B. Wandering Baseline
C. Somatic Tremor
D. Interrupted Baseline
Correct Answer: C
Explanation: Somatic tremor is caused by involuntary or voluntary muscle movement,
such as shivering or Parkinson’s disease, and appears as jagged spikes. To correct this, the
technician should provide a blanket or encourage relaxation. AC interference, by contrast,
appears as consistent, thick, rhythmic lines caused by electrical equipment.
2. Where should the V4 electrode be placed when performing a standard 12-lead EKG?
A. Fourth intercostal space, right sternal border
B. Fifth intercostal space, midclavicular line
C. Fourth intercostal space, left sternal border
D. Fifth intercostal space, anterior axillary line
,Correct Answer: B
Explanation: V4 is placed at the fifth intercostal space at the midclavicular line. This lead is
critical for viewing the apex of the heart and the anterior wall of the left ventricle.
Technicians must be careful not to place it too high or low, as incorrect vertical placement
can lead to diagnostic errors regarding myocardial infarction.
3. A patient with a known diagnosis of dextrocardia requires an EKG. How should the
technician adjust the lead placement?
A. Place the limb leads on the opposite sides only
B. Mirror the precordial leads to the right side of the chest
C. Place V1 through V6 in a vertical line on the sternum
D. Use standard placement but increase the gain
Correct Answer: B
Explanation: Dextrocardia is a condition where the heart is located on the right side of the
chest, so the precordial leads must be mirrored to the right side (V1R-V6R) to capture the
electrical activity correctly. Limb leads should also be swapped (Right arm to Left arm and
vice versa). Failure to do this will result in a tracing that shows negative P waves and QRS
complexes in Lead I, which would be misinterpreted as a lead reversal in a normal patient.
4. Which part of the heart’s conduction system is responsible for the delay that allows the
ventricles to fill with blood?
A. SA Node
, B. AV Node
C. Bundle of His
D. Purkinje Fibers
Correct Answer: B
Explanation: The AV node (atrioventricular node) slows down the electrical impulse for
approximately 0.1 seconds. This delay is essential because it allows the atria to contract
fully and empty their blood into the ventricles before ventricular contraction begins.
Without this delay, the atrial kick would be lost, significantly reducing cardiac output.
5. While performing a stress test, a patient complains of dizziness and the EKG shows a
sudden ST-segment elevation. What is the most appropriate action?
A. Continue the test but at a slower pace
B. Check the electrode connections for artifacts
C. Stop the test immediately and notify the physician
D. Administer water and ask the patient to deep breathe
Correct Answer: C
Explanation: ST-segment elevation during a stress test is a critical indicator of acute
myocardial ischemia or injury and is a mandatory reason to terminate the test. The
technician must prioritize patient safety and immediate medical intervention over
Anatomy, Lead Placement, Rhythm Interpretation
and Patient Care
1. A technician is performing a 12-lead EKG and notices a jagged, irregular baseline. The
patient is shivering due to a cold exam room. Which type of artifact is this?
A. AC Interference
B. Wandering Baseline
C. Somatic Tremor
D. Interrupted Baseline
Correct Answer: C
Explanation: Somatic tremor is caused by involuntary or voluntary muscle movement,
such as shivering or Parkinson’s disease, and appears as jagged spikes. To correct this, the
technician should provide a blanket or encourage relaxation. AC interference, by contrast,
appears as consistent, thick, rhythmic lines caused by electrical equipment.
2. Where should the V4 electrode be placed when performing a standard 12-lead EKG?
A. Fourth intercostal space, right sternal border
B. Fifth intercostal space, midclavicular line
C. Fourth intercostal space, left sternal border
D. Fifth intercostal space, anterior axillary line
,Correct Answer: B
Explanation: V4 is placed at the fifth intercostal space at the midclavicular line. This lead is
critical for viewing the apex of the heart and the anterior wall of the left ventricle.
Technicians must be careful not to place it too high or low, as incorrect vertical placement
can lead to diagnostic errors regarding myocardial infarction.
3. A patient with a known diagnosis of dextrocardia requires an EKG. How should the
technician adjust the lead placement?
A. Place the limb leads on the opposite sides only
B. Mirror the precordial leads to the right side of the chest
C. Place V1 through V6 in a vertical line on the sternum
D. Use standard placement but increase the gain
Correct Answer: B
Explanation: Dextrocardia is a condition where the heart is located on the right side of the
chest, so the precordial leads must be mirrored to the right side (V1R-V6R) to capture the
electrical activity correctly. Limb leads should also be swapped (Right arm to Left arm and
vice versa). Failure to do this will result in a tracing that shows negative P waves and QRS
complexes in Lead I, which would be misinterpreted as a lead reversal in a normal patient.
4. Which part of the heart’s conduction system is responsible for the delay that allows the
ventricles to fill with blood?
A. SA Node
, B. AV Node
C. Bundle of His
D. Purkinje Fibers
Correct Answer: B
Explanation: The AV node (atrioventricular node) slows down the electrical impulse for
approximately 0.1 seconds. This delay is essential because it allows the atria to contract
fully and empty their blood into the ventricles before ventricular contraction begins.
Without this delay, the atrial kick would be lost, significantly reducing cardiac output.
5. While performing a stress test, a patient complains of dizziness and the EKG shows a
sudden ST-segment elevation. What is the most appropriate action?
A. Continue the test but at a slower pace
B. Check the electrode connections for artifacts
C. Stop the test immediately and notify the physician
D. Administer water and ask the patient to deep breathe
Correct Answer: C
Explanation: ST-segment elevation during a stress test is a critical indicator of acute
myocardial ischemia or injury and is a mandatory reason to terminate the test. The
technician must prioritize patient safety and immediate medical intervention over
