NHA Certified EKG Technician (CET) — Questions and Answers

Question 1: What is the correct response if an ECG machine appears to have a damaged power cord?

Unplug and replug the cord to reset
Wrap the damage with tape and continue use
Remove it from service immediately and report to biomedical engineering (Correct answer)
Use it carefully and report at the end of the shift

Correct answer: Remove it from service immediately and report to biomedical engineering

Damaged electrical equipment poses a shock and fire hazard; it must be immediately removed from service and tagged for biomedical engineering inspection before further use.

Question 2: A wandering baseline artifact on an ECG is most often caused by:

A defective paper feed
Patient movement or loose electrodes (Correct answer)
A fast heart rate
AC electrical interference

Correct answer: Patient movement or loose electrodes

Baseline wander typically results from patient motion, respiration, or poorly attached electrodes.

Question 3: T-wave inversion in leads V1–V4 in an adult is most concerning for:

Atrial enlargement
First-degree AV block
Anterior ischemia or right heart strain (Correct answer)
Normal variant

Correct answer: Anterior ischemia or right heart strain

T-wave inversions in the anterior precordial leads (V1–V4) can indicate anterior wall ischemia, non-STEMI, or right ventricular strain and require clinical correlation.

Question 4: Reversing the right arm and left arm electrodes will most likely cause:

No change at all
An abnormal-looking tracing in lead I and aVR (Correct answer)
A wandering baseline
AC interference

Correct answer: An abnormal-looking tracing in lead I and aVR

Limb lead reversal produces distorted, inverted tracings, commonly obvious in leads I and aVR.

Question 5: Which of the following is an augmented (unipolar) limb lead?

aVF (Correct answer)
Lead II
V3
Lead I

Correct answer: aVF

aVF, along with aVR and aVL, are the augmented unipolar limb leads.

Question 6: What is the maximum safe leakage current from an ECG machine to the patient?

500 mA
100 mA
10 µA (microamperes) for applied part in cardiac floating connection (Correct answer)
1 A

Correct answer: 10 µA (microamperes) for applied part in cardiac floating connection

IEC 60601 limits patient auxiliary current (leakage) to 10 µA for cardiac floating-type connections, since even tiny currents can induce ventricular fibrillation if they reach the heart directly.

Question 7: The standard calibration mark on an ECG should produce a box that is:

2 mm tall
5 mm tall
20 mm tall
10 mm tall (1 millivolt) (Correct answer)

Correct answer: 10 mm tall (1 millivolt)

Standard calibration displays a 10 mm deflection representing 1 millivolt.

Question 8: What are the hallmark ECG findings of atrial fibrillation?

Wide QRS complexes with regular rhythm
Irregularly irregular rhythm with absent P waves and fibrillatory baseline (Correct answer)
Sawtooth pattern between QRS complexes
Regular rhythm with peaked T waves

Correct answer: Irregularly irregular rhythm with absent P waves and fibrillatory baseline

Atrial fibrillation shows an irregularly irregular ventricular rhythm (varying R-R intervals), absence of organized P waves replaced by fibrillatory baseline activity, and usually narrow QRS complexes.

Question 9: Where is the V1 precordial electrode correctly placed?

5th intercostal space, anterior axillary line
4th intercostal space, left sternal border
5th intercostal space, midclavicular line
4th intercostal space, right sternal border (Correct answer)

Correct answer: 4th intercostal space, right sternal border

V1 is placed in the 4th intercostal space at the right sternal border.

Question 10: The normal axis of the QRS complex in adults falls between:

-90° to -30°
+90° to +180°
-30° to +90° (Correct answer)
0° to +30° only

Correct answer: -30° to +90°

Normal QRS axis is -30° to +90°, reflecting the predominant left and inferior direction of ventricular depolarization through the His-Purkinje system.

Question 11: The PR interval on an ECG mainly reflects:

Purkinje fiber recovery
Ventricular contraction time
Conduction delay through the AV node (Correct answer)
The speed of atrial repolarization

Correct answer: Conduction delay through the AV node

The PR interval represents the time for the impulse to travel from the atria through the AV node to the ventricles.

Question 12: Lead V6 should be positioned at which anatomical landmark?

Anterior axillary line
Midaxillary line (Correct answer)
Midclavicular line
Posterior axillary line

Correct answer: Midaxillary line

V6 is placed at the midaxillary line, level with V4 and V5.

Question 13: What does a prolonged QTc interval (>500 ms) indicate clinically?

First-degree AV block
Normal variant in athletes
Left ventricular hypertrophy
Increased risk of torsades de pointes ventricular tachycardia (Correct answer)

Correct answer: Increased risk of torsades de pointes ventricular tachycardia

A QTc >500 ms significantly increases the risk of torsades de pointes, a potentially fatal polymorphic ventricular tachycardia.

Question 14: If a patient develops chest pain during an ECG recording, the technician should:

Complete the ECG and report later
Continue recording to capture the event and immediately call for clinical help (Correct answer)
Stop the machine and comfort the patient without reporting
Ask the patient to wait until symptoms subside

Correct answer: Continue recording to capture the event and immediately call for clinical help

An ECG captured during active chest pain provides critical diagnostic information; the technician should continue recording while simultaneously summoning clinical staff.

Question 15: On a normal ECG, which part of the conduction system creates the brief pause seen in the PR interval?

Purkinje fibers
AV node (Correct answer)
Bundle of His
SA node

Correct answer: AV node

The AV node deliberately delays the impulse, producing the PR interval and allowing ventricular filling.

Question 16: What do limb leads I, II, and III measure?

Only heart rate
Respiratory patterns
Blood pressure changes
Electrical activity in the frontal plane from three different angles of Einthoven's triangle (Correct answer)

Correct answer: Electrical activity in the frontal plane from three different angles of Einthoven's triangle

Limb leads I, II, and III measure cardiac electrical activity in the frontal plane, forming Einthoven's triangle: Lead I (RA to LA), Lead II (RA to LL), Lead III (LA to LL).

Question 17: In ventricular fibrillation, the ECG most characteristically shows what?

Chaotic waveforms with no identifiable QRS complexes (Correct answer)
A flat isoelectric line
Regular narrow QRS at 75 bpm
Sawtooth atrial waves

Correct answer: Chaotic waveforms with no identifiable QRS complexes

Ventricular fibrillation produces disorganized, chaotic deflections with no discernible QRS complexes.

Question 18: A rhythm shows a rate of 45 bpm with normal P waves, PR intervals, and QRS complexes. What is this rhythm?

Atrial fibrillation
Complete heart block
Sinus tachycardia
Sinus bradycardia (Correct answer)

Correct answer: Sinus bradycardia

A normal sinus pattern with a rate below 60 bpm is sinus bradycardia.

Question 19: Which patient position is standard for recording a routine resting 12-lead ECG?

Supine (lying flat on the back) (Correct answer)
Standing upright
Sitting and leaning forward
Lying on the left side

Correct answer: Supine (lying flat on the back)

A routine ECG is recorded with the patient lying supine and relaxed to minimize artifact.

Question 20: The U wave on an ECG is best seen in which leads?

V5 and V6
III and aVF
V2 and V3 (Correct answer)
aVR and aVL

Correct answer: V2 and V3

The U wave is most prominent in the mid-precordial leads V2 and V3, where it appears as a small positive deflection following the T-wave.

Question 21: The QRS complex primarily represents which cardiac event?

SA node firing
Ventricular depolarization (Correct answer)
Atrial repolarization
Atrial depolarization

Correct answer: Ventricular depolarization

The QRS complex records the rapid depolarization of the right and left ventricles.

Question 22: A corrected QT interval (QTc) is calculated to account for:

Blood pressure
Heart rate variation (Correct answer)
Lead placement differences
Patient age

Correct answer: Heart rate variation

QT interval lengthens at slower heart rates and shortens at faster rates; the QTc corrects for this, allowing comparison across different heart rates using Bazett's formula.

Question 23: A patient presents with chest pain and the ECG shows ST-segment elevation in leads II, III, and aVF. Which coronary artery is most likely involved?

Left anterior descending artery
Left circumflex artery
Left main artery
Right coronary artery (Correct answer)

Correct answer: Right coronary artery

Leads II, III, and aVF represent the inferior wall, which is most commonly supplied by the right coronary artery.

Question 24: A heart rate below 60 bpm with a normal sinus origin is termed:

Asystole
Sinus bradycardia (Correct answer)
Sinus tachycardia
Atrial flutter

Correct answer: Sinus bradycardia

Sinus bradycardia is a sinus-origin rhythm with a rate under 60 beats per minute.

Question 25: A patient on a calcium channel blocker (e.g., verapamil) is expected to show which ECG change?

Prolonged PR interval (Correct answer)
Shortened PR interval
Elevated ST segments
Widened QRS complex

Correct answer: Prolonged PR interval

Calcium channel blockers slow conduction through the AV node, prolonging the PR interval on the ECG.

Question 26: The natural pacemaker of the heart is the:

AV node
Purkinje fibers
SA node (Correct answer)
Bundle of His

Correct answer: SA node

The sinoatrial (SA) node initiates each normal heartbeat.

Question 27: A premature, wide, bizarre QRS complex that occurs earlier than expected with no preceding P wave is called what?

Junctional escape beat
Premature ventricular contraction (PVC) (Correct answer)
Premature atrial contraction (PAC)
Sinus pause

Correct answer: Premature ventricular contraction (PVC)

A wide, early QRS without a preceding P wave is a premature ventricular contraction.

Question 28: A tall, tented T wave is most classically associated with which electrolyte abnormality?

Hyponatremia
Hyperkalemia (Correct answer)
Hypercalcemia
Hypokalemia

Correct answer: Hyperkalemia

Peaked, tented T waves are a hallmark early sign of hyperkalemia.

Question 29: What is the function of the galvanometer in an ECG machine?

Amplifies electrical signals
Filters artifact
Stores patient data
Measures and records voltage differences (Correct answer)

Correct answer: Measures and records voltage differences

The galvanometer detects and records small voltage differences between electrodes, converting electrical activity into a visual tracing.

Question 30: V5 is placed at which line, level with V4 and V6?

Midaxillary line
Anterior axillary line (Correct answer)
Posterior axillary line
Midclavicular line

Correct answer: Anterior axillary line

V5 is located at the anterior axillary line, horizontal to V4 and V6.

Question 31: What is the significance of a pathological Q wave on an ECG?

It indicates right atrial enlargement
It may represent transmural myocardial infarction (scar tissue) (Correct answer)
It indicates left bundle branch block
It is always a normal septal q wave

Correct answer: It may represent transmural myocardial infarction (scar tissue)

Pathological Q waves (≥40 ms wide or ≥25% of the QRS height) represent areas of electrically silent myocardium, typically indicating old transmural infarction.

Question 32: A patient receiving IV procainamide (Class IA) for ventricular arrhythmia may develop which dangerous ECG pattern?

Inverted P waves in lead II
ST elevation in all leads
QRS widening greater than 50% of baseline (Correct answer)
PR shortening

Correct answer: QRS widening greater than 50% of baseline

Procainamide can widen the QRS by more than 50% of the baseline width, signaling toxicity and increased risk of proarrhythmia.

Question 33: A heart rate calculated at 45 bpm with normal P waves before each QRS indicates what rhythm?

Ventricular fibrillation
Sinus tachycardia
Atrial flutter
Sinus bradycardia (Correct answer)

Correct answer: Sinus bradycardia

A regular rhythm under 60 bpm with normal P waves is sinus bradycardia.

Question 34: The P wave on an ECG represents which electrical event?

Ventricular depolarization
Atrial repolarization
Atrial depolarization (Correct answer)
Ventricular repolarization

Correct answer: Atrial depolarization

The P wave reflects depolarization spreading across the atria.

Question 35: Which lead configuration would produce a completely flat line (asystole appearance) if a limb lead becomes disconnected?

The affected lead traces flat while others remain (Correct answer)
All leads go flat simultaneously
The ECG stops printing entirely
Only the chest leads are affected

Correct answer: The affected lead traces flat while others remain

A disconnected limb lead causes a flat trace in the specific lead using that electrode, not true asystole.

Question 36: An ECG technician documents a QTc of 480 ms in a patient newly started on haloperidol (antipsychotic). What is the most appropriate action?

Ignore it; QTc up to 500 ms is always normal
Immediately stop the ECG recording and send the patient home
Repeat the ECG in 30 days without notifying anyone
Document the finding and alert the supervising clinician for evaluation (Correct answer)

Correct answer: Document the finding and alert the supervising clinician for evaluation

A QTc ≥ 470 ms (men) or ≥ 480 ms (women) warrants clinical evaluation; the ECG technician should document the finding and promptly notify the supervising clinician.

Question 37: A patient taking amiodarone is most likely to show which ECG finding?

Shortened QT interval
Shortened PR interval
Delta waves
Prolonged QT interval (Correct answer)

Correct answer: Prolonged QT interval

Amiodarone prolongs ventricular repolarization, resulting in a prolonged QT interval on the ECG.

Question 38: Under HIPAA, sharing a patient's ECG tracing with a family member without consent is:

A HIPAA violation that can result in civil and criminal penalties (Correct answer)
Permitted because ECG results are not diagnostic information
Acceptable if the family member is present
Only prohibited if the patient objects verbally

Correct answer: A HIPAA violation that can result in civil and criminal penalties

ECG results are protected health information (PHI) under HIPAA; disclosing them without proper authorization constitutes a privacy breach with serious legal consequences.

Question 39: Blood rich in oxygen is delivered to the right atrium.

FALSE (Correct answer)
TRUE

Correct answer: FALSE

This statement is false. The right atrium receives deoxygenated blood from the body via the superior and inferior vena cava. Oxygen-rich blood, after being oxygenated in the lungs, returns to the *left* atrium via the pulmonary veins, from where it is then pumped to the rest of the body.

Question 40: Nitroglycerin relieves angina but its primary ECG effect during an acute ischemic episode would be:

Widening the QRS complex
Reducing or resolving ST segment depression or elevation as ischemia improves (Correct answer)
Causing peaked T waves
Producing a new left bundle branch block

Correct answer: Reducing or resolving ST segment depression or elevation as ischemia improves

Nitroglycerin reduces myocardial oxygen demand and improves coronary perfusion; resolution of ischemia-induced ST changes confirms its effectiveness.

Question 41: What is the proper position for a patient during a routine resting ECG?

Left lateral decubitus position
Standing
Supine (lying flat) with arms at sides and legs uncrossed (Correct answer)
Seated upright at 90°

Correct answer: Supine (lying flat) with arms at sides and legs uncrossed

The standard resting ECG is recorded with the patient supine, arms at the sides, and legs uncrossed to ensure consistent lead axis alignment and minimize artifact.

Question 42: The distance between two consecutive R waves is used to calculate which measurement?

P wave amplitude
ST segment
Heart rate (Correct answer)
QT interval

Correct answer: Heart rate

The R-R interval is measured to determine the ventricular heart rate.

Question 43: Which electrode color is standard for the right arm in the AHA labeling system?

White (Correct answer)
Black
Green
Red

Correct answer: White

Under AHA labeling, the right arm electrode is white.

Question 44: If a patient has a tremor, the resulting ECG artifact is best described as:

Somatic (muscle) tremor artifact (Correct answer)
Wandering baseline
AC interference
A calibration error

Correct answer: Somatic (muscle) tremor artifact

Involuntary muscle activity from tremor creates a somatic tremor artifact on the tracing.

Question 45: Heparin and warfarin are anticoagulants that do NOT directly alter the ECG. Which ECG change may appear indirectly if anticoagulation reverses a pulmonary embolism?

Shortened QRS duration
New delta waves in V1-V3
Resolution of the S1Q3T3 pattern (Correct answer)
Development of peaked T waves

Correct answer: Resolution of the S1Q3T3 pattern

A pulmonary embolism can produce the S1Q3T3 pattern; successful anticoagulation and clot resolution can lead to normalization and disappearance of this pattern.

Question 46: Which precaution is essential when performing an ECG near an MRI suite?

Record at 50 mm/sec paper speed
Use longer lead wires
Increase ECG sensitivity
Do not bring ferromagnetic ECG equipment into the MRI environment zone (Correct answer)

Correct answer: Do not bring ferromagnetic ECG equipment into the MRI environment zone

Ferromagnetic objects can become dangerous projectiles in the MRI magnetic field; only MRI-compatible ECG equipment should be used in or near an MRI suite.

Question 47: When placing chest leads on a patient with large breasts, the electrode should generally be placed:

Under the breast on the chest wall at the correct landmark (Correct answer)
At a higher intercostal space
Skipped entirely
On top of the breast tissue

Correct answer: Under the breast on the chest wall at the correct landmark

Placing the electrode beneath the breast on the chest wall keeps landmarks accurate and improves contact.

Question 48: A patient receiving thrombolytic therapy (e.g., tPA) for STEMI may show which ECG change that indicates successful reperfusion?

New onset atrial fibrillation
Development of tall R waves in V1
Permanent complete heart block
Accelerated idioventricular rhythm (AIVR) (Correct answer)

Correct answer: Accelerated idioventricular rhythm (AIVR)

Accelerated idioventricular rhythm is a classic reperfusion arrhythmia seen shortly after a blocked coronary artery reopens, indicating successful thrombolysis.

Question 49: Hypocalcemia (e.g., from loop diuretics or hypoparathyroidism) produces which ECG finding?

Delta waves
Peaked T waves
Shortened QT interval
Prolonged QT interval due to a long ST segment (Correct answer)

Correct answer: Prolonged QT interval due to a long ST segment

Hypocalcemia prolongs the ST segment, lengthening the QT interval, because calcium is essential for the plateau phase of the cardiac action potential.

Question 50: A patient taking quinidine (Class IA) develops a QTc of 560 ms. What is the most serious arrhythmia risk associated with this finding?

First-degree AV block
Sinus bradycardia
Torsades de pointes (Correct answer)
Atrial fibrillation

Correct answer: Torsades de pointes

Marked QT prolongation from quinidine predisposes to torsades de pointes, a potentially fatal polymorphic ventricular tachycardia.

Question 51: Which federal law requires healthcare facilities to maintain a safe electrical environment for patients receiving ECGs?

National Electrical Code (NEC) / Joint Commission EC standards for medical facilities (Correct answer)
HIPAA Security Rule only
Sarbanes-Oxley Act
Fair Labor Standards Act

Correct answer: National Electrical Code (NEC) / Joint Commission EC standards for medical facilities

Joint Commission Environment of Care (EC) standards, which reference the NEC and IEC 60601 requirements, mandate that healthcare facilities maintain safe electrical environments to protect patients.

Question 52: Wandering baseline artifact on an ECG tracing is most often caused by:

A fully charged machine
High paper speed
Patient movement or respiration (Correct answer)
Correct electrode placement

Correct answer: Patient movement or respiration

Baseline wander commonly results from patient movement, breathing, or loose electrodes.

Question 53: Hyperkalemia caused by potassium-sparing diuretics (e.g., spironolactone) would first appear on the ECG as:

Prolonged QT interval
Flat T waves
Short PR interval
Peaked, narrow T waves (Correct answer)

Correct answer: Peaked, narrow T waves

The earliest ECG manifestation of hyperkalemia is tall, peaked (tented) T waves due to altered ventricular repolarization.

Question 54: A delta wave on the ECG is associated with:

Wolff-Parkinson-White (WPW) syndrome pre-excitation (Correct answer)
Left bundle branch block
Hyperkalemia
Right ventricular hypertrophy

Correct answer: Wolff-Parkinson-White (WPW) syndrome pre-excitation

A delta wave is the slurred upstroke at the start of the QRS caused by accessory pathway pre-excitation in WPW syndrome, bypassing the AV node.

Question 55: Sotalol (a Class III antiarrhythmic with beta-blocking properties) increases the risk of torsades de pointes primarily because it:

Suppresses P wave formation
Widens the QRS complex beyond 200 ms
Shortens the QT interval excessively
Prolongs the QT interval (Correct answer)

Correct answer: Prolongs the QT interval

Sotalol prolongs ventricular repolarization (QT interval), creating a vulnerable window for torsades de pointes, a polymorphic ventricular tachycardia.

Question 56: A patient's rhythm strip shows progressively lengthening PR intervals until a QRS is dropped. What is this called?

First-degree AV block
Second-degree AV block, Mobitz type II
Third-degree AV block
Second-degree AV block, Mobitz type I (Wenckebach) (Correct answer)

Correct answer: Second-degree AV block, Mobitz type I (Wenckebach)

Progressive PR prolongation followed by a dropped beat characterizes Mobitz type I (Wenckebach).

Question 57: A prolonged QT interval on the ECG is clinically significant because it increases the risk of which arrhythmia?

Sinus bradycardia
Torsades de pointes (Correct answer)
Atrial flutter
First-degree AV block

Correct answer: Torsades de pointes

A prolonged QT interval predisposes the patient to torsades de pointes, a dangerous polymorphic ventricular tachycardia.

Question 58: "The QRS complex represents..." is how the nurse relates the QRS complex to the cardiac cycle.

“atrial repolarization.”
“atrial depolarization.”
"ventricular repolarization.”
"ventricular depolarization.” (Correct answer)

Correct answer: "ventricular depolarization.”

The QRS complex on an ECG tracing specifically represents ventricular depolarization, which is the electrical activation of the ventricles leading to their contraction. This is a rapid and strong electrical event, resulting in the largest deflection on the ECG. Atrial depolarization is represented by the P wave, and ventricular repolarization by the T wave.

Question 59: A rhythm that is regular with a rate over 100 bpm originating from the SA node is called:

Atrial fibrillation
Sinus tachycardia (Correct answer)
Ventricular tachycardia
Sinus bradycardia

Correct answer: Sinus tachycardia

Sinus tachycardia is a normal-appearing rhythm from the SA node exceeding 100 bpm.

Question 60: Lead V7 in a posterior ECG is placed at the:

Left posterior axillary line (Correct answer)
Left midscapular line
Left border of the spine
Right midclavicular line

Correct answer: Left posterior axillary line

V7 is located at the left posterior axillary line, at the same horizontal level as V6.

Question 61: What is the correct action if a patient refuses an ECG that has been ordered?

Skip documentation as it is a minor procedure
Respect the refusal, document it, and notify the ordering clinician (Correct answer)
Sedate the patient first
Perform the ECG anyway since it is ordered

Correct answer: Respect the refusal, document it, and notify the ordering clinician

Competent patients have the legal right to refuse procedures; the technician must respect that right, thoroughly document the refusal, and promptly notify the ordering physician.

Question 62: A rhythm alternating between one normal beat and one PVC repeatedly is termed what?

Ventricular tachycardia
Ventricular bigeminy (Correct answer)
Atrial fibrillation
Trigeminy

Correct answer: Ventricular bigeminy

A repeating pattern of one normal beat followed by one PVC is called ventricular bigeminy.

Question 63: The lead aVR normally shows predominantly negative (downward) complexes because it:

Is a chest lead over the left ventricle
Records atrial activity only
Views the heart from the right shoulder, opposite the main electrical flow (Correct answer)
Is always reversed

Correct answer: Views the heart from the right shoulder, opposite the main electrical flow

aVR looks at the heart from the upper right, so normal depolarization moves away from it.

Question 64: If the right arm and left arm electrodes are accidentally reversed, Lead I will typically show:

A flat line
No change at all
An inverted (negative) P wave and QRS (Correct answer)
AC interference

Correct answer: An inverted (negative) P wave and QRS

Limb lead reversal inverts the expected deflections in Lead I.

Question 65: For a patient with an amputated left arm, the LA electrode should be placed:

On the shoulder or upper trunk on that side (Correct answer)
On the left leg
Skip the lead entirely
On the right arm

Correct answer: On the shoulder or upper trunk on that side

The electrode is placed on the residual limb or nearest trunk area on the same side.

Question 66: When performing an ECG on a patient with a pacemaker, what should the technician note?

Disable the pacemaker before recording
Document pacemaker presence and note pacemaker spikes on the tracing (Correct answer)
Record only precordial leads to avoid interference
Use double paper speed

Correct answer: Document pacemaker presence and note pacemaker spikes on the tracing

The presence of a pacemaker should be noted in the documentation because pacemaker spikes alter waveform morphology and are essential context for accurate ECG interpretation.

Question 67: Standard ECG calibration produces a standardization mark of:

15 mm tall
10 mm tall (Correct answer)
20 mm tall
5 mm tall

Correct answer: 10 mm tall

A 1 mV calibration signal should produce a 10 mm (two large boxes) deflection.

Question 68: Which filter setting on an ECG machine is used to reduce muscle artifact?

Notch filter
High-pass filter
Band-pass filter
Low-pass filter (Correct answer)

Correct answer: Low-pass filter

A low-pass filter cuts high-frequency signals such as muscle (EMG) artifact, producing a cleaner ECG tracing.

Question 69: The T wave on the ECG corresponds to what physiological event?

Ventricular depolarization
Ventricular repolarization (Correct answer)
Atrial repolarization
Atrial depolarization

Correct answer: Ventricular repolarization

The T wave represents repolarization of the ventricles as they recover electrically.

Question 70: What artifact appears on an ECG when a patient is shivering?

Perfectly regular sharp spikes
Baseline irregularity mimicking atrial fibrillation due to muscle tremor (Correct answer)
Flat line (asystole)
Large wandering baseline

Correct answer: Baseline irregularity mimicking atrial fibrillation due to muscle tremor

Muscle tremor from shivering creates an irregular, jagged baseline that can mimic atrial fibrillation or obscure the underlying rhythm, requiring patient warming and stillness.

Question 71: The correct order to place V3 is:

Before V1 and V2
After V6
Same spot as V5
Between V2 and V4 (Correct answer)

Correct answer: Between V2 and V4

V3 is placed midway between V2 and V4.

Question 72: Which of the following patients requires modified electrode placement using a right-sided ECG?

Atrial fibrillation
Suspected right ventricular infarction (Correct answer)
Sinus tachycardia
Suspected pericarditis

Correct answer: Suspected right ventricular infarction

Right-sided leads (e.g., V4R) are used to assess suspected right ventricular infarction.

Question 73: What does an ECG technologist do when encountering a life-threatening rhythm?

Continue recording without interruption
Wait until the recording is complete before acting
Immediately alert the supervising physician or activate the emergency response system per facility protocol (Correct answer)
Attempt to treat the patient independently

Correct answer: Immediately alert the supervising physician or activate the emergency response system per facility protocol

When a life-threatening rhythm is identified (VF, VT, asystole, complete heart block), the technologist must immediately alert the physician or activate the emergency response system while maintaining patient safety.

Question 74: Which ECG change is most commonly associated with digoxin toxicity?

Wide QRS with right bundle branch block pattern
Short QT interval and tall T waves
Prolonged PR interval and ST scooping (Correct answer)
Peaked P waves and shortened PR interval

Correct answer: Prolonged PR interval and ST scooping

Digoxin toxicity characteristically causes a prolonged PR interval and a 'scooped' or sagging ST segment depression.

Question 75: Muscle tremor (somatic) artifact appears on an ECG as:

Irregular, jagged, rapid spikes (Correct answer)
A slow smooth wave
A perfectly flat line
Missing QRS complexes

Correct answer: Irregular, jagged, rapid spikes

Muscle tremor produces irregular, jagged spikes across the baseline.

Question 76: What is the normal duration of the PR interval in adults?

0.40–0.60 seconds
0.20–0.40 seconds
0.04–0.10 seconds
0.12–0.20 seconds (Correct answer)

Correct answer: 0.12–0.20 seconds

The normal PR interval is 0.12–0.20 seconds (3–5 small squares at 25 mm/sec), representing conduction time from the SA node through the AV node.

Question 77: The isoelectric line on an ECG is best defined as:

The peak of the R wave
The flat baseline where no net electrical activity is detected (Correct answer)
The top of the T wave
The deepest point of the S wave

Correct answer: The flat baseline where no net electrical activity is detected

The isoelectric line is the flat baseline representing the absence of measurable electrical deflection.

Question 78: A 60-cycle (AC) interference artifact usually looks like:

A wandering baseline
A flat isoelectric line
Absent P waves
Uniform, fine, regular spikes (Correct answer)

Correct answer: Uniform, fine, regular spikes

AC interference shows as uniform, fine, regularly-spaced spikes.

Question 79: When placing precordial leads, lead V1 is positioned where?

Left leg
Fifth intercostal space, midclavicular line
Second intercostal space, left sternal border
Fourth intercostal space, right sternal border (Correct answer)

Correct answer: Fourth intercostal space, right sternal border

Lead V1 is placed in the fourth intercostal space at the right sternal border.

Question 80: Which action is required if an ECG technician notices a life-threatening arrhythmia on the tracing?

Immediately repeat the ECG to confirm
File the ECG and wait for physician review
Notify the responsible clinician immediately and do not leave the patient alone (Correct answer)
Disconnect the electrodes and inform the next shift

Correct answer: Notify the responsible clinician immediately and do not leave the patient alone

Critical ECG findings must be reported immediately to the responsible clinician; the technician should remain with the patient until qualified help arrives.

Question 81: What is the purpose of the right leg (RL) electrode in ECG safety design?

Serves as the electrical ground/reference to reduce interference and protect patient (Correct answer)
Records right heart signals
Records the inferior wall
Controls paper speed

Correct answer: Serves as the electrical ground/reference to reduce interference and protect patient

The RL electrode is the driven right leg circuit that acts as electrical ground, reducing common-mode interference and providing a safety reference to protect the patient.

Question 82: A completely flat line on the ECG with no electrical activity indicates:

First-degree block
Sinus rhythm
Asystole (Correct answer)
Sinus arrhythmia

Correct answer: Asystole

Asystole is the absence of electrical activity, shown as a flat line.

Question 83: Which beta-blocker effect on the ECG helps an ECG technician recognize its therapeutic use?

Prolonged PR interval and slower heart rate (Correct answer)
Widened QRS and peaked T waves
Delta waves on multiple leads
Shortened PR interval and faster heart rate

Correct answer: Prolonged PR interval and slower heart rate

Beta-blockers slow AV node conduction, producing a prolonged PR interval, and reduce heart rate by decreasing SA node automaticity.

Question 84: To prepare skin for electrode placement, the technician should first:

Warm the skin with a heat lamp
Clean and lightly abrade the site (Correct answer)
Apply electrode directly to oily skin
Rub lotion on the site

Correct answer: Clean and lightly abrade the site

Cleaning and gentle abrasion removes oils and dead skin for better conduction.

Question 85: Which of the following is a correct step in preparing skin for ECG electrode placement?

Apply lotion before attaching electrodes
Skip preparation if patient is diaphoretic
Wipe skin with alcohol and allow to dry (Correct answer)
Attach electrodes over clothing

Correct answer: Wipe skin with alcohol and allow to dry

Cleaning the skin with alcohol removes oils and debris, and allowing it to dry before electrode placement lowers impedance for a quality tracing.

Question 86: The LL (left leg) electrode color in the AHA system is:

Red (Correct answer)
White
Green
Black

Correct answer: Red

The left leg electrode is red in the AHA color code.

Question 87: How should ECG electrodes and lead wires be cleaned between patients?

Autoclave all lead wires after each use
No cleaning needed if no visible soilage
Rinse with tap water only
Disinfect with EPA-registered disinfectant wipes per facility policy (Correct answer)

Correct answer: Disinfect with EPA-registered disinfectant wipes per facility policy

Reusable lead wires must be disinfected with EPA-registered disinfectant wipes between patients per infection control guidelines to prevent cross-contamination.

Question 88: The normal duration of a QRS complex in an adult is approximately:

0.20 to 0.40 seconds
0.40 to 0.60 seconds
0.06 to 0.10 seconds (Correct answer)
0.12 to 0.20 seconds

Correct answer: 0.06 to 0.10 seconds

A normal QRS complex lasts less than 0.12 seconds, typically 0.06 to 0.10.

Question 89: A patient receiving IV adenosine for SVT would most likely show which transient ECG finding immediately after the dose?

Complete heart block or brief asystole (Correct answer)
Ventricular tachycardia
Prolonged QT interval
Atrial fibrillation

Correct answer: Complete heart block or brief asystole

Adenosine transiently blocks AV node conduction, often producing a brief period of complete heart block or asystole before normal rhythm resumes.

Question 90: Which drug interaction should an ECG technician be aware of that can compound QT prolongation risk?

Amiodarone plus azithromycin (Correct answer)
Metoprolol plus lisinopril
Aspirin plus warfarin
Furosemide plus spironolactone

Correct answer: Amiodarone plus azithromycin

Amiodarone and azithromycin both independently prolong the QT interval; combining them significantly increases the risk of torsades de pointes.

Question 91: A wandering baseline artifact is most commonly caused by:

Nearby AC power lines
Muscle tremor
Poor electrode contact or patient movement/respiration (Correct answer)
Incorrect paper speed

Correct answer: Poor electrode contact or patient movement/respiration

Loose electrodes, lotion on skin, or breathing cause the baseline to drift.

Question 92: 60-cycle (AC) interference on an ECG appears as:

A completely flat line
A slowly drifting baseline
Random spikes with no pattern
A thick, fuzzy fine oscillation on the baseline (Correct answer)

Correct answer: A thick, fuzzy fine oscillation on the baseline

AC interference produces uniform fine, fuzzy oscillations from nearby electrical sources.

Question 93: Which of the following is a common cause of poor electrode adhesion leading to artifact?

Normal sinus rhythm
Diaphoretic (sweaty) or oily skin (Correct answer)
Slow heart rate
High paper speed

Correct answer: Diaphoretic (sweaty) or oily skin

Sweaty or oily skin reduces electrode adhesion and causes poor-quality tracings.

Question 94: Electrodes V1 and V2 are both placed in which intercostal space?

4th intercostal space (Correct answer)
6th intercostal space
2nd intercostal space
5th intercostal space

Correct answer: 4th intercostal space

V1 and V2 are both located in the 4th intercostal space on either side of the sternum.

Question 95: Hypokalemia from loop diuretic use (e.g., furosemide) produces which characteristic ECG change?

Elevated J-point with delta waves
Shortened QT interval
Flat or inverted T waves and prominent U waves (Correct answer)
Peaked T waves and narrow QRS

Correct answer: Flat or inverted T waves and prominent U waves

Hypokalemia flattens or inverts the T wave and causes prominent U waves (deflection after the T wave) due to delayed ventricular repolarization.

Question 96: What does a normal sinus rhythm look like on an ECG?

Irregular R-R intervals
No P waves visible
Regular P waves before each QRS complex, consistent PR interval, rate 60-100 bpm, and upright P waves in lead II (Correct answer)
QRS complexes wider than 120ms

Correct answer: Regular P waves before each QRS complex, consistent PR interval, rate 60-100 bpm, and upright P waves in lead II

Normal sinus rhythm shows regular rhythm with each P wave followed by a QRS complex, PR interval 0.12-0.20 seconds, QRS duration <0.12 seconds, and rate between 60-100 bpm.

Question 97: What does a jagged, irregular baseline on an ECG tracing most likely indicate?

Poor electrode contact or muscle artifact (Correct answer)
Pacemaker malfunction
Atrial fibrillation
Ventricular tachycardia

Correct answer: Poor electrode contact or muscle artifact

A jagged, irregular baseline is typically caused by poor electrode contact, patient movement, or muscle tremor artifact rather than a cardiac dysrhythmia.

Question 98: Which class of antiarrhythmic drugs primarily works by blocking sodium channels and may widen the QRS complex?

Class II
Class III
Class I (Correct answer)
Class IV

Correct answer: Class I

Class I antiarrhythmics (e.g., lidocaine, flecainide) block sodium channels, slowing depolarization and widening the QRS complex.

Question 99: Which finding on a rhythm strip indicates a normal sinus rhythm?

Chaotic wavy baseline
Sawtooth flutter waves
Absent P waves at 40 bpm
Upright P wave before every QRS at 60-100 bpm (Correct answer)

Correct answer: Upright P wave before every QRS at 60-100 bpm

Normal sinus rhythm shows a consistent upright P wave preceding each QRS at a rate of 60-100 bpm.

Question 100: Lithium toxicity can cause which ECG finding that mimics a naturally occurring rhythm disturbance?

ST elevation identical to Brugada pattern
T wave flattening or inversion and sinoatrial block resembling sick sinus syndrome (Correct answer)
Prolonged QRS with right bundle branch block
Delta waves in multiple leads

Correct answer: T wave flattening or inversion and sinoatrial block resembling sick sinus syndrome

Lithium toxicity can flatten or invert T waves and disrupt SA node function, producing sinoatrial block or sinus arrest patterns similar to sick sinus syndrome.

Question 101: Before performing an ECG, the technician must obtain:

Patient identification verification and verbal consent for the procedure (Correct answer)
Written consent signed by a physician
Insurance authorization only
A physician's verbal order only, no patient interaction needed

Correct answer: Patient identification verification and verbal consent for the procedure

The technician must verify patient identity using two identifiers and explain the procedure to obtain the patient's informed consent before placing any electrodes.

Question 102: On standard ECG paper, how many seconds does one small (1 mm) box represent horizontally?

0.01 seconds
0.10 seconds
0.20 seconds
0.04 seconds (Correct answer)

Correct answer: 0.04 seconds

At the standard 25 mm/sec speed, each small horizontal box equals 0.04 seconds.

Question 103: A patient's monitor shows a completely flat line with no electrical activity. What rhythm is this and what should be verified first?

Asystole; confirm lead placement in more than one lead (Correct answer)
Atrial flutter; give medication
Ventricular fibrillation; defibrillate immediately
Sinus rhythm; no action needed

Correct answer: Asystole; confirm lead placement in more than one lead

A flat line suggests asystole, but the technician should first confirm it in multiple leads to rule out a lead-off artifact.

Question 104: What is the most likely cause of a wandering baseline on the ECG tracing?

Correct electrode placement
AC electrical interference
High paper speed
Patient movement or breathing (Correct answer)

Correct answer: Patient movement or breathing

Wandering baseline is usually caused by patient movement, respiration, or loose electrodes.

Question 105: The SA node, the heart's natural pacemaker, is located in which chamber?

Left atrium
Right atrium (Correct answer)
Right ventricle
Left ventricle

Correct answer: Right atrium

The sinoatrial node sits in the upper wall of the right atrium.

Question 106: Which standard governs the electrical safety requirements for ECG machines used in US hospitals?

Association for the Advancement of Medical Instrumentation (AAMI) / IEC 60601 standard (Correct answer)
CMS billing standard
FDA Drug Approval Standard
OSHA bloodborne pathogens standard

Correct answer: Association for the Advancement of Medical Instrumentation (AAMI) / IEC 60601 standard

AAMI/IEC 60601 standards specify patient safety requirements for medical electrical equipment, including maximum allowable leakage currents for ECG machines.

Question 107: Which condition might require modified electrode placement or a note to the physician?

Right-handed patient
A talkative patient
A patient wearing a watch
A patient with an amputated limb (Correct answer)

Correct answer: A patient with an amputated limb

An amputated limb requires modified placement and documentation.

Question 108: Before applying chest electrodes, the technician should:

Clean and prep the skin site (Correct answer)
Leave skin oily for adhesion
Apply lotion to the skin
Place electrodes over bone only

Correct answer: Clean and prep the skin site

Skin should be cleaned and prepped to ensure good electrode contact.

Question 109: If lead aVR shows a positive deflection in all waveforms, what should the technician check?

Machine calibration
Precordial lead placement
Paper speed
Right arm and left arm electrode reversal (Correct answer)

Correct answer: Right arm and left arm electrode reversal

Lead aVR normally shows predominantly negative deflections; if it appears positive, right arm (RA) and left arm (LA) electrode reversal is the most likely cause.

Question 110: How many electrodes are placed on the body to record a standard 12-lead ECG?

10 (Correct answer)
12
6
15

Correct answer: 10

Ten electrodes (four limb and six chest) produce the 12 leads of a standard ECG.

Question 111: On standard ECG paper, how much time does one small (1 mm) box represent?

1.0 second
0.20 seconds
0.10 seconds
0.04 seconds (Correct answer)

Correct answer: 0.04 seconds

At the standard 25 mm/sec paper speed, each small box equals 0.04 seconds.

Question 112: The body uses the heart for two main purposes: oxygen and nutrition transportation.

TRUE (Correct answer)
FALSE

Correct answer: TRUE

The heart acts as the central pump of the circulatory system, a vital role in maintaining life. Its primary function is to circulate blood throughout the body, delivering oxygen and essential nutrients to all tissues and organs. Simultaneously, it removes metabolic waste products like carbon dioxide, ensuring cellular health and proper organ function.

Question 113: Three or more PVCs in a row at a rate over 100 bpm should be identified as what?

Ventricular tachycardia (Correct answer)
Sinus tachycardia
Bigeminy
Atrial flutter

Correct answer: Ventricular tachycardia

A run of three or more consecutive PVCs above 100 bpm meets the definition of ventricular tachycardia.

Question 114: A sawtooth baseline pattern with atrial waves at about 300 bpm and a regular 2:1 ventricular response best describes which rhythm?

Atrial fibrillation
Atrial flutter (Correct answer)
Sinus rhythm
Ventricular tachycardia

Correct answer: Atrial flutter

The sawtooth flutter waves near 300 bpm with a fixed conduction ratio are classic for atrial flutter.

Question 115: A junctional rhythm arising from the AV node typically produces which finding?

Wide QRS at 180 bpm
Inverted or absent P waves with a rate of 40-60 bpm (Correct answer)
Upright P waves at 100 bpm
Sawtooth flutter waves

Correct answer: Inverted or absent P waves with a rate of 40-60 bpm

Junctional rhythms arise near the AV node, causing inverted or absent P waves at a rate of about 40-60 bpm.

Question 116: What is the significance of pathological Q waves on an ECG?

They indicate electrolyte imbalance
They only appear during exercise
They are always a normal finding
They indicate previous myocardial infarction with irreversible tissue death in the affected area (Correct answer)

Correct answer: They indicate previous myocardial infarction with irreversible tissue death in the affected area

Pathological Q waves (>1mm wide, >25% of R wave height) indicate prior transmural myocardial infarction where dead heart muscle has been replaced by scar tissue, serving as a permanent marker of past heart attack.

Question 117: The ST segment on the ECG represents:

The period between ventricular depolarization and repolarization (plateau phase) (Correct answer)
Atrial repolarization
His-Purkinje conduction
P-wave production

Correct answer: The period between ventricular depolarization and repolarization (plateau phase)

The ST segment corresponds to phase 2 (plateau) of the ventricular action potential, during which no net current flows and all cells are in an equally depolarized state.

Question 118: Which way does lead II go on an ECG?

30 degrees
60 degrees (Correct answer)
0 degrees
90 degrees

Correct answer: 60 degrees

In the standard limb lead configuration (Einthoven's triangle), Lead II is an inferior lead that runs from the right arm (negative) to the left leg (positive). It is oriented at an angle of +60 degrees on the frontal plane, making it a crucial lead for assessing the heart's electrical axis and inferior wall changes.

Question 119: Wandering baseline and fuzzy, irregular artifact on a rhythm strip is most commonly caused by what?

Complete heart block
True ventricular fibrillation
Patient movement or loose electrodes (Correct answer)
A prolonged QT interval

Correct answer: Patient movement or loose electrodes

Motion and poor electrode contact create artifact that can mimic arrhythmias, so the technician should check leads and patient position.

Question 120: A flat line on a single lead while others record normally most likely means:

Too much gel
A disconnected or broken lead wire (Correct answer)
Normal finding
Cardiac arrest

Correct answer: A disconnected or broken lead wire

A single flat lead usually indicates a loose, disconnected, or faulty electrode/wire.

NHA Certified EKG Technician (CET)

The NHA CET exam certifies EKG technicians on patient safety, EKG acquisition, and rhythm analysis/interpretation, validating competency to perform electrocardiograms in clinical settings.

120

Questions

120 min

Time Limit

70%

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