Certified EKG Technician (CET)
Examination Professional Certification
Exam Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. When performing an EKG on a patient, which of the following is the
standard paper speed? A. 12.5 mm/sec B. 25 mm/sec C. 50 mm/sec D. 75
mm/sec Rationale: The standard speed for recording an EKG is 25 mm/sec,
which allows for the accurate measurement of intervals and amplitudes.
Other speeds are used only for specific clinical scenarios like identifying fast
tachycardias.
2. Which lead is recorded by placing the positive electrode on the left arm and
the negative electrode on the right arm? A. Lead I B. Lead II C. Lead III D.
aVR Rationale: Lead II is part of the bipolar limb leads and follows
Einthoven’s Law, measuring the electrical potential between the right arm
and left leg, but historically defined by the potential difference between
right arm and left arm as the path.
3. A patient is experiencing a heart rate of 140/min. Which of the following
rhythms should the EKG technician expect to see? A. Sinus bradycardia B.
Junctional rhythm C. Sinus tachycardia D. Idioventricular rhythm Rationale:
Sinus tachycardia is defined as a sinus rhythm with a heart rate greater than
100/min. Given the rate of 140/min, this fits the classification of sinus
tachycardia.
4. Which of the following waves represents ventricular repolarization? A. P
wave B. QRS complex C. T wave D. U wave Rationale: The T wave is the
deflection produced by the repolarization of the ventricles. The P wave
, represents atrial depolarization, and the QRS complex represents ventricular
depolarization.
5. When applying electrodes for a Holter monitor, which of the following is the
most important step to ensure quality tracing? A. Abrading the skin with a
dry gauze B. Applying alcohol-based cleaner only C. Applying the leads over
bony prominences D. Ensuring the wires are stretched tight Rationale:
Abrading the skin removes dead skin cells and oils, which reduces electrical
impedance and improves signal quality. Bony prominences should be
avoided to prevent muscle artifact.
6. Which of the following is a common cause of a wandering baseline artifact?
A. Improper grounding of the machine B. Electrical interference from
nearby devices C. Loose or dried-out electrodes D. Patient muscle tremors
Rationale: Wandering baseline is often caused by poor electrode contact or
patient movement. Ensuring electrodes are fresh and adhered properly to
clean skin resolves this issue.
7. If a patient is diagnosed with a third-degree heart block, which of the
following is expected on the EKG? A. Prolonged PR interval B. Dropped QRS
complexes C. Absent relationship between P waves and QRS complexes D.
Missing P waves Rationale: In a third-degree (complete) heart block, the
atria and ventricles beat independently. There is no correlation between the
P waves and the QRS complexes.
8. Which lead is considered the most common rhythm strip lead? A. V1 B. II C.
V6 D. aVL Rationale: Lead II provides the best visualization of P wave
morphology and the overall atrial-ventricular conduction sequence. It is the
standard lead for continuous monitoring.
9. Which of the following is the correct placement for lead V4? A. Fourth
intercostal space, right sternal border B. Fourth intercostal space, left
sternal border C. Fifth intercostal space, left midclavicular line D. Fifth
intercostal space, left anterior axillary line Rationale: Anatomical landmarks
for V4 require placing the electrode at the intersection of the fifth intercostal
, space and the midclavicular line to capture the best view of the left
ventricular apex.
10.A technician notices a flat line on the EKG. What should be the first action?
A. Document the death of the patient B. Call a code blue immediately C.
Check the patient's pulse and lead connections D. Increase the gain of the
machine Rationale: Before assuming the patient is in asystole, it is critical to
rule out technical issues like loose lead wires or a dislodged electrode.
Checking the pulse confirms the clinical status of the patient.
11.Which of the following represents the total time for ventricular
depolarization? A. P-R interval B. QRS duration C. Q-T interval D. R-R
interval Rationale: The QRS duration measures the time required for
electrical impulses to travel through the ventricles, causing contraction. It is
typically 0.06 to 0.10 seconds.
12.Which of the following is an example of somatic tremor? A. Baseline
fluctuation B. Patient shivering or Parkinsonian movement C. Alternating
current interference D. A broken lead wire Rationale: Somatic tremor is
caused by involuntary or voluntary muscle movement. Shivering and
tremors cause high-frequency spikes on the EKG tracing.
13.What is the standard amplitude (sensitivity) setting for an EKG machine? A.
10 mm/mV B. 5 mm/mV C. 20 mm/mV D. 25 mm/mV Rationale: Standard
sensitivity is set to 10 mm/mV. If the complexes are too small, the sensitivity
may be increased to 20 mm/mV, or decreased to 5 mm/mV if they are too
large.
14.How many leads are used in a standard 12-lead EKG? A. 3 B. 5 C. 12 D. 15
Rationale: Despite only 10 electrodes being placed on the patient, they are
configured to produce 12 distinct electrical views of the heart.
15.What is the primary purpose of the P wave? A. Ventricular contraction B.
Atrial depolarization C. Ventricular repolarization D. Atrial repolarization
Rationale: The P wave represents the electrical activation (depolarization) of
the right and left atria.
Examination Professional Certification
Exam Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. When performing an EKG on a patient, which of the following is the
standard paper speed? A. 12.5 mm/sec B. 25 mm/sec C. 50 mm/sec D. 75
mm/sec Rationale: The standard speed for recording an EKG is 25 mm/sec,
which allows for the accurate measurement of intervals and amplitudes.
Other speeds are used only for specific clinical scenarios like identifying fast
tachycardias.
2. Which lead is recorded by placing the positive electrode on the left arm and
the negative electrode on the right arm? A. Lead I B. Lead II C. Lead III D.
aVR Rationale: Lead II is part of the bipolar limb leads and follows
Einthoven’s Law, measuring the electrical potential between the right arm
and left leg, but historically defined by the potential difference between
right arm and left arm as the path.
3. A patient is experiencing a heart rate of 140/min. Which of the following
rhythms should the EKG technician expect to see? A. Sinus bradycardia B.
Junctional rhythm C. Sinus tachycardia D. Idioventricular rhythm Rationale:
Sinus tachycardia is defined as a sinus rhythm with a heart rate greater than
100/min. Given the rate of 140/min, this fits the classification of sinus
tachycardia.
4. Which of the following waves represents ventricular repolarization? A. P
wave B. QRS complex C. T wave D. U wave Rationale: The T wave is the
deflection produced by the repolarization of the ventricles. The P wave
, represents atrial depolarization, and the QRS complex represents ventricular
depolarization.
5. When applying electrodes for a Holter monitor, which of the following is the
most important step to ensure quality tracing? A. Abrading the skin with a
dry gauze B. Applying alcohol-based cleaner only C. Applying the leads over
bony prominences D. Ensuring the wires are stretched tight Rationale:
Abrading the skin removes dead skin cells and oils, which reduces electrical
impedance and improves signal quality. Bony prominences should be
avoided to prevent muscle artifact.
6. Which of the following is a common cause of a wandering baseline artifact?
A. Improper grounding of the machine B. Electrical interference from
nearby devices C. Loose or dried-out electrodes D. Patient muscle tremors
Rationale: Wandering baseline is often caused by poor electrode contact or
patient movement. Ensuring electrodes are fresh and adhered properly to
clean skin resolves this issue.
7. If a patient is diagnosed with a third-degree heart block, which of the
following is expected on the EKG? A. Prolonged PR interval B. Dropped QRS
complexes C. Absent relationship between P waves and QRS complexes D.
Missing P waves Rationale: In a third-degree (complete) heart block, the
atria and ventricles beat independently. There is no correlation between the
P waves and the QRS complexes.
8. Which lead is considered the most common rhythm strip lead? A. V1 B. II C.
V6 D. aVL Rationale: Lead II provides the best visualization of P wave
morphology and the overall atrial-ventricular conduction sequence. It is the
standard lead for continuous monitoring.
9. Which of the following is the correct placement for lead V4? A. Fourth
intercostal space, right sternal border B. Fourth intercostal space, left
sternal border C. Fifth intercostal space, left midclavicular line D. Fifth
intercostal space, left anterior axillary line Rationale: Anatomical landmarks
for V4 require placing the electrode at the intersection of the fifth intercostal
, space and the midclavicular line to capture the best view of the left
ventricular apex.
10.A technician notices a flat line on the EKG. What should be the first action?
A. Document the death of the patient B. Call a code blue immediately C.
Check the patient's pulse and lead connections D. Increase the gain of the
machine Rationale: Before assuming the patient is in asystole, it is critical to
rule out technical issues like loose lead wires or a dislodged electrode.
Checking the pulse confirms the clinical status of the patient.
11.Which of the following represents the total time for ventricular
depolarization? A. P-R interval B. QRS duration C. Q-T interval D. R-R
interval Rationale: The QRS duration measures the time required for
electrical impulses to travel through the ventricles, causing contraction. It is
typically 0.06 to 0.10 seconds.
12.Which of the following is an example of somatic tremor? A. Baseline
fluctuation B. Patient shivering or Parkinsonian movement C. Alternating
current interference D. A broken lead wire Rationale: Somatic tremor is
caused by involuntary or voluntary muscle movement. Shivering and
tremors cause high-frequency spikes on the EKG tracing.
13.What is the standard amplitude (sensitivity) setting for an EKG machine? A.
10 mm/mV B. 5 mm/mV C. 20 mm/mV D. 25 mm/mV Rationale: Standard
sensitivity is set to 10 mm/mV. If the complexes are too small, the sensitivity
may be increased to 20 mm/mV, or decreased to 5 mm/mV if they are too
large.
14.How many leads are used in a standard 12-lead EKG? A. 3 B. 5 C. 12 D. 15
Rationale: Despite only 10 electrodes being placed on the patient, they are
configured to produce 12 distinct electrical views of the heart.
15.What is the primary purpose of the P wave? A. Ventricular contraction B.
Atrial depolarization C. Ventricular repolarization D. Atrial repolarization
Rationale: The P wave represents the electrical activation (depolarization) of
the right and left atria.
