NHA Certified EKG Technician (CET) — Questions and Answers

Question 1: Which organization offers the Certified Cardiographic Technician (CCT) credential?

The Joint Commission (TJC)
American Heart Association (AHA)
National Healthcareer Association (NHA)
Cardiovascular Credentialing International (CCI) (Correct answer)

Correct answer: Cardiovascular Credentialing International (CCI)

Cardiovascular Credentialing International (CCI) is a prominent independent credentialing organization for cardiovascular technology professionals. They offer various certifications, including the Certified Cardiographic Technician (CCT) credential, which validates expertise in performing advanced ECGs, stress tests, and other non-invasive cardiac procedures.

Question 2: What ions are primarily responsible for the cardiac action potential?

Chloride and phosphate
Only sodium and potassium
Iron and magnesium
Sodium, potassium, and calcium (Correct answer)

Correct answer: Sodium, potassium, and calcium

The cardiac action potential involves sodium influx (depolarization), calcium influx (plateau phase), and potassium efflux (repolarization), each contributing to different phases.

Question 3: Which of the following ECG findings suggests pericarditis rather than acute MI?

ST elevation limited to two contiguous leads
Reciprocal ST depression in opposite leads
Diffuse ST elevation with PR segment depression in multiple leads (Correct answer)
New left bundle branch block

Correct answer: Diffuse ST elevation with PR segment depression in multiple leads

Pericarditis classically causes diffuse (saddle-shaped) ST elevation across many leads with PR depression, unlike the localized changes of MI.

Question 4: Where should the V4 precordial electrode be placed?

Fourth intercostal space right sternal border
Second intercostal space left sternal border
Fifth intercostal space at the midclavicular line (Correct answer)
Fifth intercostal space at the anterior axillary line

Correct answer: Fifth intercostal space at the midclavicular line

V4 is placed at the fifth intercostal space at the midclavicular line, serving as the reference point for V5 and V6 placement.

Question 5: An ECG shows a rate of 150 bpm with narrow QRS complexes and no visible P waves. Which arrhythmia should be considered first?

Ventricular tachycardia
Junctional tachycardia
Sinus tachycardia
Atrial flutter with 2:1 conduction (Correct answer)

Correct answer: Atrial flutter with 2:1 conduction

Atrial flutter at a typical atrial rate of 300 bpm with 2:1 AV conduction produces a ventricular rate of approximately 150 bpm; flutter waves may be hidden in the QRS or T wave.

Question 6: For a patient with a heart rate of 150 bpm on a rhythm strip at 25 mm/sec, the R-R interval measures approximately how many large boxes?

1 large box
2 large boxes (Correct answer)
10 large boxes
5 large boxes

Correct answer: 2 large boxes

At 25 mm/sec, 300 ÷ 150 bpm = 2 large boxes per R-R interval (the '300 method').

Question 7: When a patient's ECG shows motion artifact making interpretation difficult, what is the FIRST action the ECG technician should take?

Reapply all electrodes with fresh conductive gel
Ask the patient to relax and lie still, then repeat the recording (Correct answer)
Immediately notify the physician of uninterpretable tracing
Increase filter settings to eliminate noise

Correct answer: Ask the patient to relax and lie still, then repeat the recording

Patient movement is the most common cause of artifact, and instructing the patient to remain still and relaxed should be the first step before any equipment adjustments.

Question 8: The V4 precordial lead is placed at which location?

5th intercostal space, midclavicular line (Correct answer)
5th intercostal space, anterior axillary line
4th intercostal space, left sternal border
6th intercostal space, midaxillary line

Correct answer: 5th intercostal space, midclavicular line

V4 is placed at the 5th intercostal space at the left midclavicular line.

Question 9: What information should be documented at the START of a Holter monitor recording?

The physician's preliminary interpretation of the baseline rhythm
Patient height and weight only
Only the patient's chief complaint in their own words
Date, time, patient identification, and electrode placement sites (Correct answer)

Correct answer: Date, time, patient identification, and electrode placement sites

Documenting the start date, time, patient identification, and electrode placement ensures accurate analysis, proper correlation with the diary, and authentication of the recording.

Question 10: A patient's ECG shows a PR interval of 0.28 seconds with no dropped beats. Which condition does this represent?

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

Correct answer: First-degree AV block

First-degree AV block is defined by a PR interval >0.20 seconds with every P wave conducted to the ventricles.

Question 11: What is the primary purpose of continuous cardiac monitoring in a hospital setting?

Tracking blood pressure trends
Measuring blood oxygen levels
Early detection of life-threatening arrhythmias (Correct answer)
Monitoring respiratory rate

Correct answer: Early detection of life-threatening arrhythmias

Continuous cardiac monitoring is used to detect dangerous arrhythmias early so that timely intervention can be initiated.

Question 12: What ECG finding is characteristic of hyperkalemia at serum potassium levels above 6.5 mEq/L?

Broad notched P waves
Peaked, narrow, symmetric T waves (Correct answer)
Prolonged QT interval with U waves
Short PR interval with delta waves

Correct answer: Peaked, narrow, symmetric T waves

Hyperkalemia first manifests as tall, peaked, narrow, symmetric (tent-shaped) T waves due to accelerated ventricular repolarization.

Question 13: What does reciprocal change mean on an ECG?

Identical changes in all 12 leads
P waves appearing after QRS complexes
T wave inversion in limb leads only
ST depression in leads opposite to those showing ST elevation (Correct answer)

Correct answer: ST depression in leads opposite to those showing ST elevation

Reciprocal changes are ST depressions seen in leads opposite to the primary area of ST elevation during acute MI, helping confirm the diagnosis and localize the infarct.

Question 14: Which anticoagulant is commonly used to prevent stroke in atrial fibrillation?

Warfarin or DOACs (direct oral anticoagulants) (Correct answer)
Acetaminophen
Statins
Aspirin alone

Correct answer: Warfarin or DOACs (direct oral anticoagulants)

Warfarin and DOACs (like apixaban, rivaroxaban) are used in atrial fibrillation to prevent blood clots from forming in the fibrillating atria, reducing stroke risk.

Question 15: What is the standard paper speed for ECG recording?

10 mm/sec
100 mm/sec
50 mm/sec
25 mm/sec (Correct answer)

Correct answer: 25 mm/sec

Standard ECG paper speed is 25 mm/second, where each small box represents 0.04 seconds and each large box represents 0.20 seconds.

Question 16: After applying a Holter monitor, which step should be completed before the patient leaves the office?

Measure the patient's blood pressure in both arms
Apply a simultaneous 12-lead ECG for comparison
Review a sample ECG tracing to confirm all leads have adequate signal quality (Correct answer)
Have the patient perform a 10-minute treadmill walk

Correct answer: Review a sample ECG tracing to confirm all leads have adequate signal quality

Reviewing a sample ECG tracing confirms that all electrodes are recording properly and that signal quality is adequate before the patient departs for their monitoring period.

Question 17: What ECG finding in a monitored patient should prompt the nurse to call a rapid response immediately?

PACs with a compensatory pause
Sustained ventricular tachycardia with a heart rate of 180 bpm (Correct answer)
First-degree AV block
Sinus bradycardia at 58 bpm with no symptoms

Correct answer: Sustained ventricular tachycardia with a heart rate of 180 bpm

Sustained ventricular tachycardia is a life-threatening arrhythmia requiring immediate clinical assessment and intervention.

Question 18: What is the purpose of the filter setting on an ECG machine?

To reduce artifact and electrical noise without distorting waveforms (Correct answer)
To speed up paper output
To calibrate the voltage standard
To increase the amplitude of P waves

Correct answer: To reduce artifact and electrical noise without distorting waveforms

ECG filters reduce high- and low-frequency noise while preserving clinically relevant waveform morphology.

Question 19: What is typically the minimum educational requirement for ECG certification?

High school diploma or equivalent (Correct answer)
No educational requirement
Associate degree in nursing
Bachelor's degree in healthcare

Correct answer: High school diploma or equivalent

For most entry-level healthcare certifications, including ECG technician, a high school diploma or its equivalent (GED) is the foundational educational requirement. This ensures that candidates possess the basic literacy, numeracy, and general knowledge necessary to understand the training material and perform job duties effectively. While further education is beneficial, it is not typically a prerequisite for initial ECG certification.

Question 20: What is the normal heart rate range for adults at rest?

40-60 beats per minute
120-150 beats per minute
100-120 beats per minute
60-100 beats per minute (Correct answer)

Correct answer: 60-100 beats per minute

Normal resting heart rate for adults is 60-100 bpm. Below 60 is bradycardia and above 100 is tachycardia.

Question 21: Which of the following best describes the electrophysiological difference between SA nodal cells and ventricular myocytes?

Both cell types have identical action potential morphology
SA nodal cells have a stable resting potential of -90 mV; ventricular cells spontaneously depolarize
SA nodal cells lack a stable resting potential and spontaneously depolarize; ventricular cells have a stable -90 mV resting potential (Correct answer)
Ventricular cells use Ca2+ for Phase 0; SA nodal cells use Na+

Correct answer: SA nodal cells lack a stable resting potential and spontaneously depolarize; ventricular cells have a stable -90 mV resting potential

SA nodal cells have an unstable 'maximum diastolic potential' of about -60 mV and rely on Phase 4 spontaneous depolarization, while ventricular myocytes maintain a stable -90 mV resting potential.

Question 22: What does the standard calibration signal on ECG paper look like?

1 mV = 10 mm tall square wave (Correct answer)
1 mV = 5 mm tall square wave
0.5 mV = 10 mm tall square wave
2 mV = 10 mm tall square wave

Correct answer: 1 mV = 10 mm tall square wave

Standard ECG calibration is 1 mV = 10 mm (two large boxes) in amplitude.

Question 23: What happens if limb lead electrodes are placed on the wrong limbs?

Nothing, the machine compensates automatically
The machine will not turn on
The ECG tracing will show incorrect or inverted waveforms (Correct answer)
Only the heart rate will be affected

Correct answer: The ECG tracing will show incorrect or inverted waveforms

Incorrect lead placement produces misleading ECG patterns that can mimic pathology, such as lead reversal producing apparent axis deviation or inverted complexes.

Question 24: A patient's ECG shows a QRS duration of 160 ms with a left bundle branch block pattern. What does this indicate electrophysiologically?

Accessory pathway pre-excitation is present
The PR interval is prolonged due to AV nodal disease
The SA node is firing too rapidly for the AV node to keep up
Conduction fails in the left bundle branch; the left ventricle depolarizes slowly via cell-to-cell spread from the right (Correct answer)

Correct answer: Conduction fails in the left bundle branch; the left ventricle depolarizes slowly via cell-to-cell spread from the right

LBBB means the left bundle is blocked; the RV depolarizes normally then the LV depolarizes slowly via myocardial cell-to-cell conduction, producing a wide, bizarre QRS.

Question 25: Which organization provides guidelines for in-hospital cardiac monitoring practice in the US?

Joint Commission (TJC)
American Heart Association (AHA) (Correct answer)
Centers for Medicare and Medicaid Services (CMS)
American Medical Association (AMA)

Correct answer: American Heart Association (AHA)

The AHA publishes evidence-based practice standards for in-hospital cardiac monitoring.

Question 26: A patient's ECG shows PR interval of 320 ms that is constant across all beats. How is this classified?

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

Correct answer: First-degree AV block

First-degree AV block is defined as a PR interval greater than 200 ms that remains constant with every beat conducted through the AV node.

Question 27: What does the term 'ambulatory' mean in the context of ambulatory ECG monitoring?

The patient is monitored only during emergency transport
The ECG is analyzed remotely by a physician in real time
The patient can move around freely and perform normal activities during the recording (Correct answer)
Monitoring occurs exclusively during structured walking exercises

Correct answer: The patient can move around freely and perform normal activities during the recording

Ambulatory refers to the patient's ability to move freely and continue normal daily activities during monitoring, unlike stationary hospital telemetry systems.

Question 28: Which of the following rhythms would show a 'sawtooth' flutter wave pattern at approximately 300 bpm?

Junctional tachycardia
Multifocal atrial tachycardia
Atrial flutter (Correct answer)
Atrial fibrillation

Correct answer: Atrial flutter

Atrial flutter produces regular sawtooth flutter waves (F waves) typically at 250–350 bpm, best seen in leads II, III, and aVF.

Question 29: What artifact can be caused by patient movement during ECG recording?

ST elevation
Wandering baseline and muscle tremor artifact (Correct answer)
Bundle branch block pattern
Peaked T waves

Correct answer: Wandering baseline and muscle tremor artifact

Patient movement causes wandering baseline (slow undulation) and muscle tremor artifact (irregular, fine oscillations), which can obscure the true ECG signal.

Question 30: When troubleshooting a wandering baseline artifact on a 12-lead ECG, which corrective action is most effective?

Increase the paper speed to 50 mm/s
Ask the patient to hold their breath briefly during acquisition (Correct answer)
Switch to a bipolar limb lead configuration
Reduce the gain setting on the ECG machine

Correct answer: Ask the patient to hold their breath briefly during acquisition

Respiratory movement is the primary cause of wandering baseline, and having the patient hold their breath during recording eliminates this motion artifact.

Question 31: Which layer of the heart wall contains contractile muscle tissue?

Endocardium
Pericardium
Myocardium (Correct answer)
Epicardium

Correct answer: Myocardium

The myocardium is the thick middle layer composed of cardiac muscle cells responsible for heart contraction.

Question 32: V3 is placed between which two leads?

V1 and V2
V4 and V5
V1 and V3
V2 and V4 (Correct answer)

Correct answer: V2 and V4

V3 is placed directly between V2 and V4 to provide transitional precordial coverage.

Question 33: A patient's ECG alarm is alarming frequently with no clinical change — what is this called?

Alarm fatigue (Correct answer)
Threshold desensitization
False positive monitoring
Artifact interference

Correct answer: Alarm fatigue

Alarm fatigue occurs when frequent non-actionable alarms cause staff to become desensitized, posing a patient safety risk.

Question 34: Which AAMI/IEC standard governs ECG electrode performance requirements in the US?

ANSI/AAMI ES60601
ISO 13485
IEC 60601-1
AAMI EC12 (Correct answer)

Correct answer: AAMI EC12

AAMI EC12 is the US standard specifying performance requirements for disposable ECG electrodes.

Question 35: Which lead is best for identifying atrial activity?

Lead I
Lead V6
Lead V1 (Correct answer)
Lead aVL

Correct answer: Lead V1

Lead V1, positioned over the right sternal border, is closest to the atria and provides the best visualization of P waves and atrial activity.

Question 36: What is the conduction velocity of the His-Purkinje system, and why is it important?

0.05 m/s; ensures slow ventricular filling
0.5 m/s; prevents re-entry circuits
1 m/s; matches atrial conduction speed
4 m/s; enables near-simultaneous ventricular depolarization for effective contraction (Correct answer)

Correct answer: 4 m/s; enables near-simultaneous ventricular depolarization for effective contraction

The His-Purkinje system conducts at ~4 m/s, the fastest in the heart, ensuring both ventricles depolarize nearly simultaneously for coordinated ejection.

Question 37: Which scenario might disqualify someone from pursuing ECG certification?

Being unfamiliar with advanced cardiac techniques
Lacking a high school diploma or equivalent (Correct answer)
Having no prior ECG experience
Not working directly with patients yet

Correct answer: Lacking a high school diploma or equivalent

A high school diploma or its equivalent is a fundamental prerequisite for most professional certification programs, including ECG certification. This ensures that candidates possess the basic academic skills necessary to comprehend course material, follow instructions, and perform job duties. Without this foundational education, individuals typically cannot enroll in or complete accredited certification programs.

Question 38: What should you do if the ECG shows 60-cycle (60 Hz) interference?

Replace the ECG machine
Increase paper speed
Check for nearby electrical equipment and ensure proper grounding (Correct answer)
Repeat the ECG tomorrow

Correct answer: Check for nearby electrical equipment and ensure proper grounding

60 Hz interference creates a thick, fuzzy baseline caused by nearby electrical equipment. Solutions include ensuring proper grounding, unplugging nearby devices, and checking cable integrity.

Question 39: Which ECG finding is characteristic of atrial fibrillation?

Irregularly irregular rhythm with no P waves (Correct answer)
Regular rhythm with tall P waves
Wide QRS complexes only
Saw-tooth pattern

Correct answer: Irregularly irregular rhythm with no P waves

Atrial fibrillation shows an irregularly irregular ventricular rhythm with fibrillatory baseline waves replacing organized P waves.

Question 40: Which structure delays electrical impulses between the atria and ventricles?

Purkinje fibers
AV node (Correct answer)
SA node
Bundle branches

Correct answer: AV node

The AV node provides a critical delay of about 0.1 seconds, allowing the atria to finish contracting before the ventricles begin.

Question 41: What does atropine do to the heart rate?

Has no effect on heart rate
Increases it by blocking vagal (parasympathetic) tone (Correct answer)
Decreases it
Stops the heart temporarily

Correct answer: Increases it by blocking vagal (parasympathetic) tone

Atropine blocks the parasympathetic (vagal) input to the heart via muscarinic receptors, which removes the vagal brake and increases heart rate. It is used for symptomatic bradycardia.

Question 42: A Holter monitor is most appropriate for evaluating a patient who experiences palpitations:

Intermittently throughout daily activities over 24–48 hours (Correct answer)
Continuously in the clinic during a resting 12-lead ECG
Only during heavy physical exertion on a treadmill
Exclusively during sleep

Correct answer: Intermittently throughout daily activities over 24–48 hours

A Holter monitor records continuous ECG over 24–48 hours, capturing arrhythmias that occur unpredictably during normal daily activities.

Question 43: What does the P wave on an ECG represent?

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

Correct answer: Atrial depolarization

The P wave represents the electrical depolarization spreading through the atria, triggering atrial contraction.

Question 44: What does 'signal-averaged ECG' (SAECG) primarily detect?

ST-segment elevation patterns
QT interval prolongation
P-wave morphology changes
Late potentials indicating risk for ventricular arrhythmias (Correct answer)

Correct answer: Late potentials indicating risk for ventricular arrhythmias

SAECG detects ventricular late potentials, which indicate areas of slow conduction predisposing to re-entrant ventricular arrhythmias.

Question 45: A 60-year-old male presents with chest pain. The ECG shows ST depression in leads V1-V3. Which condition should be ruled out first?

Digitalis effect
Right bundle branch block
Posterior MI (reciprocal changes) (Correct answer)
Anterior STEMI

Correct answer: Posterior MI (reciprocal changes)

ST depression in V1-V3 may represent reciprocal changes of a posterior MI; posterior leads (V7-V9) should be obtained to look for ST elevation confirming posterior STEMI.

Question 46: An ECG technician notes that the patient has a permanent pacemaker. Which expected finding should be documented but does NOT indicate a problem?

Pacemaker spikes followed by wide QRS complexes (Correct answer)
QTc interval of 480 ms
ST elevation in V1 and V2
P waves absent in all leads

Correct answer: Pacemaker spikes followed by wide QRS complexes

Ventricular pacing produces pacemaker spikes followed by wide, aberrant-appearing QRS complexes, which is the expected normal pacemaker pattern.

Question 47: A patient with chest pain has ST elevation in leads V1–V4. Which coronary artery territory is most likely occluded?

Left anterior descending artery (LAD) (Correct answer)
Right coronary artery (RCA)
Left circumflex artery (LCx)
Posterior descending artery (PDA)

Correct answer: Left anterior descending artery (LAD)

The LAD supplies the anterior wall and septum, so anterior STEMI (V1–V4 ST elevation) indicates LAD occlusion.

Question 48: What is the function of the coronary sinus?

Regulates heart rate
Produces cardiac enzymes
Delivers oxygenated blood to the myocardium
Collects deoxygenated blood from cardiac veins (Correct answer)

Correct answer: Collects deoxygenated blood from cardiac veins

The coronary sinus is a large vein that collects deoxygenated blood from the cardiac veins and empties it into the right atrium.

Question 49: What is the primary purpose of a patient activity diary during Holter monitoring?

To document total sleep duration
To record hourly blood pressure readings
To correlate reported symptoms with corresponding ECG rhythm changes (Correct answer)
To track only medication dosing times

Correct answer: To correlate reported symptoms with corresponding ECG rhythm changes

The patient diary allows technicians and physicians to correlate the timing of reported symptoms such as palpitations or dizziness with the ECG tracing at that exact time.

Question 50: How do you calculate heart rate from an ECG strip using the 300 method?

Divide 300 by the number of large boxes between two R waves (Correct answer)
Multiply the P-P interval by 60
Count the number of QRS complexes in 6 seconds
Count small boxes between R waves and divide by 5

Correct answer: Divide 300 by the number of large boxes between two R waves

The 300 method divides 300 by the number of large boxes between consecutive R waves (R-R interval) to estimate heart rate quickly.

Question 51: On a standard 12-lead ECG recorded at 25 mm/s, each small box (1 mm) represents how much time?

0.20 seconds (200 ms)
0.04 seconds (40 ms)
0.10 seconds (100 ms)
0.02 seconds (20 ms) (Correct answer)

Correct answer: 0.02 seconds (20 ms)

At standard speed of 25 mm/s, each 1 mm small box = 0.04 s/box ÷ 2 = 0.04 s per small box; actually each small box = 1mm / 25mm/s = 0.04 s.

Question 52: Where is the V1 precordial lead electrode placed?

4th intercostal space, right sternal border (Correct answer)
5th intercostal space, left midclavicular line
4th intercostal space, left sternal border
2nd intercostal space, right sternal border

Correct answer: 4th intercostal space, right sternal border

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

Question 53: A patient's ECG shows a sudden straight line. What is the FIRST action the nurse should take?

Begin CPR immediately
Check the patient and verify lead connections before assuming asystole (Correct answer)
Call a code blue
Administer epinephrine

Correct answer: Check the patient and verify lead connections before assuming asystole

A flat line on a monitor most often reflects a loose lead or electrode, not asystole; always assess the patient first.

Question 54: What does the Osborn wave (J wave) on ECG suggest?

Hypothermia (Correct answer)
Hyperkalemia
Pulmonary embolism
Hyperthermia

Correct answer: Hypothermia

An Osborn (J) wave is a positive deflection at the J-point and is a hallmark ECG finding in hypothermia.

Question 55: What is the primary function of an EKG technician during an ECG procedure?

Diagnose cardiac conditions based on the results
Interpret lab results related to cardiac enzymes
Administer medications for heart conditions
Set up the equipment and ensure accurate lead placement (Correct answer)

Correct answer: Set up the equipment and ensure accurate lead placement

The primary function of an EKG technician is to accurately perform the ECG procedure. This involves preparing the patient, correctly attaching the electrodes (leads) to specific locations on the body, operating the ECG machine, and ensuring a clear and accurate recording. Technicians are not typically trained or authorized to diagnose conditions or administer medications; those are responsibilities of physicians or other licensed medical professionals.

Question 56: What is the typical recording duration of a standard Holter monitor?

6 to 12 hours
72 to 96 hours
7 to 14 days
24 to 48 hours (Correct answer)

Correct answer: 24 to 48 hours

Standard Holter monitors record cardiac activity continuously for 24 to 48 hours to capture daily rhythm variations and correlate symptoms with arrhythmias.

Question 57: What is the recommended minimum number of leads monitored continuously in a telemetry unit?

2 (Correct answer)
12
6
1

Correct answer: 2

Continuous telemetry monitoring typically requires at least 2 leads to improve arrhythmia detection.

Question 58: Which finding on a 12-lead ECG is most suggestive of left ventricular hypertrophy (LVH)?

S wave in V1 plus R wave in V5 or V6 exceeding 35 mm (Correct answer)
R wave in aVR greater than 8 mm
QRS duration greater than 120 ms
PR interval greater than 200 ms

Correct answer: S wave in V1 plus R wave in V5 or V6 exceeding 35 mm

The Sokolow-Lyon criterion (SV1 + RV5 or RV6 ≥ 35 mm) is a widely used ECG voltage criterion for diagnosing LVH.

Question 59: What is the standard number of leads in a 12-lead ECG?

6 leads from 6 electrodes
12 leads from 10 electrodes (Correct answer)
10 leads from 10 electrodes
12 leads from 12 electrodes

Correct answer: 12 leads from 10 electrodes

A 12-lead ECG uses 10 physical electrodes (4 limb, 6 precordial) to generate 12 different electrical views of the heart.

Question 60: When should a 12-lead ECG be performed for a patient with chest pain?

Within 10 minutes of arrival (Correct answer)
At the next scheduled appointment
Only if symptoms persist for 1 hour
After blood work results return

Correct answer: Within 10 minutes of arrival

Guidelines recommend obtaining a 12-lead ECG within 10 minutes of arrival for any patient presenting with chest pain to rapidly identify acute myocardial infarction.

Question 61: Why are statins prescribed for cardiac patients?

To reduce blood sugar
To treat arrhythmias
To increase heart rate
To lower LDL cholesterol and reduce atherosclerosis risk (Correct answer)

Correct answer: To lower LDL cholesterol and reduce atherosclerosis risk

Statins inhibit HMG-CoA reductase, reducing LDL cholesterol production and decreasing the risk of atherosclerotic plaque buildup in coronary and other arteries.

Question 62: Which of the following is a potential benefit of obtaining advanced ECG certifications?

Increased ability to perform complex cardiac surgeries
Enhanced job prospects in specialized cardiology departments (Correct answer)
Automatic salary increases in all healthcare facilities
Reduced workload and responsibilities

Correct answer: Enhanced job prospects in specialized cardiology departments

Advanced ECG certifications demonstrate a higher level of expertise and specialized knowledge in cardiac diagnostics. This makes professionals more attractive to employers in specialized cardiology departments, such as those focusing on electrophysiology, stress testing, or advanced cardiac monitoring. These roles often come with increased responsibilities, better compensation, and more focused career paths, enhancing overall job prospects.

Question 63: What is the standard paper speed used for ECG recordings in the US?

50 mm/sec
10 mm/sec
100 mm/sec
25 mm/sec (Correct answer)

Correct answer: 25 mm/sec

The standard ECG paper speed in the US is 25 mm/sec.

Question 64: What is the most common cause of pseudo-Q waves (QS pattern) in leads V1-V2 in an otherwise healthy patient?

Incorrect precordial electrode placement (too high) (Correct answer)
Left posterior fascicular block
Right ventricular hypertrophy
Old anteroseptal myocardial infarction

Correct answer: Incorrect precordial electrode placement (too high)

Placing V1 and V2 electrodes one or two intercostal spaces too high is the most common technical cause of QS patterns mimicking anteroseptal infarction.

Question 65: Why might employers prioritize hiring ECG-certified professionals?

They bring guaranteed reductions in healthcare costs.
They are legally allowed to diagnose cardiac conditions.
They require less supervision during procedures. (Correct answer)
They are more likely to excel in pharmaceutical sales.

Correct answer: They require less supervision during procedures.

Employers prioritize hiring ECG-certified professionals because certification validates that an individual has met established standards of knowledge and competency. This means certified ECG technicians are generally more reliable, capable of performing procedures accurately and independently, and require less direct supervision from physicians or senior staff. This efficiency and demonstrated skill level are highly valued in busy healthcare settings.

Question 66: A patient with a permanent pacemaker has an ECG showing pacemaker spikes without subsequent QRS complexes. What is the most likely diagnosis?

Pacemaker failure to capture (Correct answer)
Pacemaker oversensing
Pacemaker undersensing
Normal demand pacing behavior

Correct answer: Pacemaker failure to capture

Failure to capture occurs when the pacemaker spike fires but fails to depolarize the myocardium, producing spikes not followed by QRS complexes.

Question 67: ST segment elevation most commonly indicates:

Normal variant in all cases
Acute myocardial injury (Correct answer)
Pulmonary embolism
Chronic heart failure

Correct answer: Acute myocardial injury

ST elevation is a hallmark finding of acute myocardial infarction (heart attack), indicating acute injury to the heart muscle.

Question 68: Which ECG change is the earliest and most sensitive indicator of acute hyperkalemia?

Tall, peaked (tented) T waves (Correct answer)
ST segment depression
Wide, flat P waves
Prolonged QT interval

Correct answer: Tall, peaked (tented) T waves

Tall, narrow, peaked T waves are the earliest ECG manifestation of hyperkalemia, appearing when serum potassium rises above ~5.5 mEq/L.

Question 69: Which condition requires telemetry monitoring according to AHA Class II guidelines?

Isolated hypertension without cardiac history
Stable angina with no recent change in symptoms
Post-op hernia repair in a healthy 30-year-old
Newly diagnosed heart failure with reduced ejection fraction (Correct answer)

Correct answer: Newly diagnosed heart failure with reduced ejection fraction

New heart failure with reduced ejection fraction carries risk of arrhythmias, making it an AHA Class II monitoring indication.

Question 70: Lead II records electrical activity between which electrodes?

Right arm and left arm
Right arm and left leg (Correct answer)
Right leg and left arm
Left arm and left leg

Correct answer: Right arm and left leg

Lead II measures the potential difference between the right arm (negative) and left leg (positive), roughly aligned with the heart's electrical axis.

Question 71: An ECG technician observes a 60-cycle (60 Hz) interference pattern on the tracing. Which corrective measure is most appropriate?

Increase the paper speed
Switch from AC to DC mode on the ECG machine
Replace the ECG paper
Check electrode contact and ensure leads are not crossing electrical equipment (Correct answer)

Correct answer: Check electrode contact and ensure leads are not crossing electrical equipment

60 Hz AC interference is caused by poor electrode contact or proximity to electrical equipment; improving electrode contact and repositioning cables eliminates this artifact.

Question 72: During ECG acquisition, the standardization mark (calibration pulse) should show a deflection of:

0.1 mV (1 mm tall)
0.5 mV (5 mm tall)
1.0 mV (10 mm tall) (Correct answer)
2.0 mV (20 mm tall)

Correct answer: 1.0 mV (10 mm tall)

Standard ECG calibration is 1 mV = 10 mm; the calibration pulse verifies the machine is recording at correct sensitivity.

Question 73: Delta waves on an ECG are associated with which pre-excitation syndrome?

Brugada syndrome
Long QT syndrome
Lown-Ganong-Levine syndrome
Wolff-Parkinson-White syndrome (Correct answer)

Correct answer: Wolff-Parkinson-White syndrome

Wolff-Parkinson-White syndrome causes delta waves due to early ventricular activation via an accessory pathway (Bundle of Kent).

Question 74: Which finding on a rhythm strip most reliably confirms sinus rhythm?

Positive P wave in lead II preceding each QRS (Correct answer)
Regular R-R intervals
Heart rate between 60 and 100 bpm
QRS duration less than 0.12 seconds

Correct answer: Positive P wave in lead II preceding each QRS

Sinus rhythm requires that the SA node drive the heart, confirmed by an upright P wave in lead II before every QRS complex.

Question 75: A patient's ECG shows a regularly irregular rhythm with a pattern of grouped beating. Which arrhythmia is most likely?

Complete heart block
Multifocal atrial tachycardia
Atrial flutter with variable block
Second-degree AV block Mobitz I (Wenckebach) (Correct answer)

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

Wenckebach block produces grouped beating due to progressive PR prolongation until a beat is dropped, creating a regularly irregular pattern.

Question 76: What type of training is commonly required before obtaining ECG certification?

Extensive laboratory research
In-depth pharmacology courses
Surgical training
Hands-on clinical practice with ECG equipment (Correct answer)

Correct answer: Hands-on clinical practice with ECG equipment

ECG certification programs heavily emphasize practical skills because performing an ECG involves direct patient interaction and precise equipment operation. Hands-on clinical practice ensures that technicians can correctly place electrodes, troubleshoot common issues, and obtain accurate readings, which are critical for proper diagnosis. This practical experience is essential for developing the competency needed to work effectively and safely in a clinical setting.

Question 77: A patient arrives for an ECG with lotion on the chest. The best immediate action is to:

Proceed with the ECG and note the artifact
Wipe the skin dry with a towel and apply electrodes
Apply extra electrode gel over the lotion
Clean the skin with an alcohol prep pad and allow it to dry (Correct answer)

Correct answer: Clean the skin with an alcohol prep pad and allow it to dry

Alcohol prep pads remove oils and lotion that impair electrode adhesion; allowing the skin to dry fully ensures good contact.

Question 78: What ECG change is seen with hyperkalemia?

Delta waves
Peaked T waves (Correct answer)
Short QT interval
Inverted P waves only

Correct answer: Peaked T waves

Elevated potassium levels cause tall, peaked T waves as one of the earliest ECG manifestations, progressing to widened QRS and sine wave pattern if severe.

Question 79: What is the most common cause of a wandering baseline on an ECG?

Equipment malfunction
A cardiac arrhythmia
Patient movement or poor electrode contact (Correct answer)
Electromagnetic interference

Correct answer: Patient movement or poor electrode contact

Wandering baseline is most commonly caused by patient movement, respiratory motion, or poor electrode-skin contact. Proper skin preparation and electrode placement minimize this artifact.

Question 80: Why is skin preparation important before applying ECG electrodes?

To make electrode removal easier
To sterilize the skin for a procedure
To reduce impedance and improve signal quality (Correct answer)
To prevent allergic reactions

Correct answer: To reduce impedance and improve signal quality

Cleaning the skin with alcohol and lightly abrading removes oils, dead skin cells, and debris that increase electrical impedance, resulting in cleaner ECG signals.

Question 81: Artifact resembling a sinusoidal pattern at a rate close to the respiratory rate is most likely caused by:

Battery failure in the ECG machine
Electromagnetic interference from nearby equipment
Loose precordial electrode contact
Patient movement of the limb electrodes during breathing (Correct answer)

Correct answer: Patient movement of the limb electrodes during breathing

Respiratory artifact occurs when limb electrode movement with each breath creates a slow, cyclical baseline wander synchronized with respiration.

Question 82: When recording a right-sided ECG (V3R-V6R), what is the primary clinical indication?

Evaluation of left bundle branch block
Suspected left ventricular aneurysm
Assessment of posterior wall motion
Suspected right ventricular MI in the setting of inferior STEMI (Correct answer)

Correct answer: Suspected right ventricular MI in the setting of inferior STEMI

Right-sided leads are obtained when inferior STEMI is present to detect right ventricular involvement, which changes management (avoid nitrates and diuretics).

Question 83: When applying chest electrodes for a 12-lead ECG, V4 should be placed at:

Fourth intercostal space, left sternal border
Sixth intercostal space, midaxillary line
Fifth intercostal space, midclavicular line (Correct answer)
Fifth intercostal space, anterior axillary line

Correct answer: Fifth intercostal space, midclavicular line

V4 is placed at the fifth intercostal space along the left midclavicular line, and V5/V6 are positioned relative to V4.

Question 84: What is the recommended ECG lead for detecting ST-segment changes in the anterior wall of the left ventricle?

V4 or V5 (Correct answer)
aVL
V1
Lead II

Correct answer: V4 or V5

V4 and V5 provide the best sensitivity for detecting anterior wall ST changes during ischemia monitoring.

Question 85: A normal PR interval ranges from:

0.12 to 0.20 seconds (Correct answer)
0.40 to 0.60 seconds
0.06 to 0.10 seconds
0.24 to 0.36 seconds

Correct answer: 0.12 to 0.20 seconds

The normal PR interval is 0.12-0.20 seconds (3-5 small boxes), representing the time from atrial depolarization to ventricular depolarization.

Question 86: What is the antidote for warfarin overdose?

Naloxone
Protamine sulfate
Vitamin K (Correct answer)
Flumazenil

Correct answer: Vitamin K

Vitamin K reverses the anticoagulant effects of warfarin by restoring the production of vitamin K-dependent clotting factors (II, VII, IX, X).

Question 87: A prolonged QT interval increases the risk of:

Torsades de pointes (Correct answer)
Pericarditis
First-degree heart block
Atrial flutter

Correct answer: Torsades de pointes

Prolonged QT interval can lead to torsades de pointes, a dangerous polymorphic ventricular tachycardia that can degenerate into ventricular fibrillation.

Question 88: A patient's ECG shows a QRS duration of 140 ms with a broad, notched R wave in leads I, aVL, V5, and V6, and absence of septal Q waves. What is the diagnosis?

Left bundle branch block (Correct answer)
Hyperkalemia
Right bundle branch block
Left anterior fascicular block

Correct answer: Left bundle branch block

Left bundle branch block (LBBB) produces broad, notched R waves (M-shaped) in lateral leads (I, aVL, V5-V6) with absent septal Q waves and QRS ≥ 120 ms.

Question 89: What is the purpose of the QTc (corrected QT) interval calculation in monitoring?

To detect ST changes independent of rate
To adjust QT for heart rate and identify prolongation risk for torsades de pointes (Correct answer)
To measure P-wave duration accurately
To calculate left ventricular ejection fraction

Correct answer: To adjust QT for heart rate and identify prolongation risk for torsades de pointes

QTc corrects the QT interval for heart rate, allowing standardized assessment of prolongation risk for fatal arrhythmias.

Question 90: Which lead best visualizes the inferior wall of the left ventricle?

Leads V4 and V5
Leads I and aVL
Leads II, III, and aVF (Correct answer)
Leads V1 and V2

Correct answer: Leads II, III, and aVF

Leads II, III, and aVF face the inferior surface of the left ventricle and detect changes associated with inferior MI.

Question 91: Which electrolyte abnormality produces tall, peaked T waves on ECG?

Hypercalcemia
Hyponatremia
Hyperkalemia (Correct answer)
Hypokalemia

Correct answer: Hyperkalemia

Hyperkalemia characteristically produces tall, narrow, peaked T waves, especially in precordial leads.

Question 92: Which chamber of the heart has the thickest muscular wall?

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

Correct answer: Left ventricle

The left ventricle has the thickest wall because it must generate enough pressure to pump blood throughout the entire systemic circulation.

Question 93: What is one reason prior healthcare experience might be required for ECG certification?

It ensures familiarity with patient care and medical protocols. (Correct answer)
It demonstrates the ability to use diagnostic imaging machines.
It validates proficiency in medical coding systems.
It proves knowledge of pharmaceutical therapies.

Correct answer: It ensures familiarity with patient care and medical protocols.

Prior healthcare experience is valuable for ECG certification because it provides candidates with a foundational understanding of patient care principles, medical terminology, and clinical environments. This familiarity helps technicians interact professionally with patients, maintain sterile techniques, and adhere to essential medical protocols. Such experience contributes to safer and more effective patient interactions during ECG procedures.

Question 94: Which electrode placement error would most likely cause an artificially inverted P wave in lead II?

Reversing the left arm and left leg electrodes
Reversing the right leg and left leg electrodes
Placing the V1 electrode one intercostal space too high
Reversing the right arm and left arm electrodes (Correct answer)

Correct answer: Reversing the right arm and left arm electrodes

Swapping the right arm (RA) and left arm (LA) electrodes inverts leads I and aVL and reverses the polarity of lead II, causing an inverted P wave.

Question 95: In a patient with atrial fibrillation, which ECG feature is characteristically absent?

R waves
Distinct P waves (Correct answer)
QRS complexes
T waves

Correct answer: Distinct P waves

Atrial fibrillation produces chaotic atrial activity with no discernible P waves, replaced by irregular fibrillatory baseline.

Question 96: What is the likely interpretation when an ECG shows varying QRS morphologies with no identifiable P waves and an irregularly irregular rhythm at 90 bpm?

Accelerated idioventricular rhythm
Atrial fibrillation with aberrant conduction (Correct answer)
Ventricular tachycardia
Multifocal atrial tachycardia

Correct answer: Atrial fibrillation with aberrant conduction

Atrial fibrillation with aberrant conduction (rate-related bundle branch block) produces irregularly irregular rhythm with varying QRS morphology and absent P waves.

Question 97: What is the voltage gain setting used in half-standardization on an ECG?

10 mm/mV
5 mm/mV (Correct answer)
20 mm/mV
2.5 mm/mV

Correct answer: 5 mm/mV

Half-standardization sets gain to 5 mm/mV, used when waveforms are too tall at normal gain.

Question 98: When measuring QT interval, the measurement should end at:

The J point
The point where the T wave returns to the isoelectric baseline (Correct answer)
The beginning of the U wave
The peak of the T wave

Correct answer: The point where the T wave returns to the isoelectric baseline

The QT interval is measured from the start of the QRS to the point where the T wave returns to baseline, not its peak.

Question 99: A technician notices 60-Hz electrical interference on the ECG tracing. The most appropriate first step is to:

Reposition the patient to the right lateral decubitus position
Apply a notch filter and re-record
Check and improve electrode-skin contact and grounding (Correct answer)
Increase the paper speed to 50 mm/sec

Correct answer: Check and improve electrode-skin contact and grounding

60-Hz artifact usually results from poor electrode contact or nearby electrical interference; improving skin prep and contact is the first corrective step.

Question 100: What does a delta wave on an ECG indicate?

Hyperkalemia
Pre-excitation via an accessory pathway (Wolff-Parkinson-White syndrome) (Correct answer)
Hypercalcemia
Right bundle branch block

Correct answer: Pre-excitation via an accessory pathway (Wolff-Parkinson-White syndrome)

A delta wave is a slurred upstroke at the beginning of the QRS caused by ventricular pre-excitation in WPW syndrome.

Question 101: What is conductivity in cardiac tissue?

The ability to transmit electrical impulses from cell to cell (Correct answer)
The ability to contract
The ability to respond to stimuli
The ability to return to resting state

Correct answer: The ability to transmit electrical impulses from cell to cell

Conductivity is the ability of cardiac cells to transmit electrical impulses to adjacent cells through gap junctions, ensuring coordinated contraction throughout the heart.

Question 102: Which of the following workplaces is most common for ECG-certified professionals?

Research universities
Retail pharmacies
Law firms
Diagnostic laboratories (Correct answer)

Correct answer: Diagnostic laboratories

ECG-certified professionals, often EKG technicians, primarily work in settings where diagnostic tests are performed. This includes diagnostic laboratories, hospitals, clinics, and physician's offices. Their role is to operate the ECG equipment and obtain accurate readings, which are then interpreted by physicians for diagnosis.

Question 103: How should an ECG technician respond if a patient reports chest pain during the ECG recording?

Stop the recording and send the patient back to the waiting area
Repeat the recording after 30 minutes
Complete the recording immediately, document the symptom, and notify the supervising clinician (Correct answer)
Administer oxygen and wait for symptoms to pass before recording

Correct answer: Complete the recording immediately, document the symptom, and notify the supervising clinician

Completing the ECG during active symptoms captures potentially diagnostic changes; notifying a clinician ensures timely evaluation.

Question 104: What is the safe current limit to prevent microshock injury in a patient with an intracardiac catheter?

1 milliampere (1 mA)
10 microamperes (10 µA) (Correct answer)
100 milliamperes (100 mA)
50 microamperes (50 µA)

Correct answer: 10 microamperes (10 µA)

Patients with direct cardiac connections (e.g., pacemaker leads) are at risk of microshock; the safe limit is 10 µA.

Question 105: An ECG shows a short PR interval of 100 ms, a delta wave, and a wide QRS. What is the diagnosis?

Accelerated junctional rhythm
Wolff-Parkinson-White (WPW) syndrome (Correct answer)
First-degree AV block with aberrant conduction
Left bundle branch block

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

WPW syndrome is characterized by a short PR interval, slurred upstroke (delta wave) of the QRS, and widened QRS due to ventricular pre-excitation via an accessory pathway.

Question 106: Which patient activity should be specifically avoided during standard Holter monitoring?

Walking or mild exercise
Sleeping on their side
Consuming caffeine
Showering or immersing in water (Correct answer)

Correct answer: Showering or immersing in water

Most standard Holter monitors are not waterproof and can be damaged or lose electrode contact if exposed to water during bathing or showering.

Question 107: Why is a baseline ECG important before starting certain medications?

To detect pre-existing QT prolongation or other abnormalities (Correct answer)
To determine the patient's blood pressure
To assess lung function
To measure oxygen saturation

Correct answer: To detect pre-existing QT prolongation or other abnormalities

A baseline ECG identifies pre-existing cardiac abnormalities (especially QT prolongation) that certain medications could worsen, preventing dangerous drug-induced arrhythmias.

Question 108: A patient receiving digoxin shows scooped ST-segment depression on ECG. What is this called?

ST injury pattern
Reciprocal change
Digitalis effect (Correct answer)
Digoxin toxicity

Correct answer: Digitalis effect

The scooped or 'Salvador Dali mustache' ST depression is the classic digitalis effect, a predictable pharmacologic ECG change.

Question 109: An ECG shows QRS complexes preceded by P waves in leads I and aVL but inverted P waves before QRS in lead II. What does this indicate?

Left bundle branch block
Right atrial enlargement
Ectopic atrial rhythm originating in the low atrium or near the AV node (Correct answer)
Dextrocardia

Correct answer: Ectopic atrial rhythm originating in the low atrium or near the AV node

Inverted P waves in the inferior leads (II, III, aVF) with upright P in lateral leads suggest a low atrial or junctional ectopic pacemaker firing retrogradely.

Question 110: What is a common requirement for renewing ECG certification?

Completing continuing education units (CEUs) (Correct answer)
Submitting research papers
Passing a physical fitness test
Performing a certain number of ECGs annually

Correct answer: Completing continuing education units (CEUs)

Most healthcare certifications, including ECG certification, require professionals to complete continuing education units (CEUs) to maintain their credentials. CEUs ensure that certified individuals stay updated with the latest advancements, best practices, and regulatory changes in their field. This ongoing education helps maintain their competency and ensures they continue to provide high-quality patient care.

Question 111: What does sinus rhythm mean on an ECG?

The heart is beating irregularly
The heart rhythm originates from the SA node (Correct answer)
The ventricles are pacing the heart
There is a conduction block

Correct answer: The heart rhythm originates from the SA node

Sinus rhythm means the electrical impulse originates from the sinoatrial node, the heart's natural pacemaker, producing a normal, regular rhythm with consistent P waves before each QRS.

Question 112: What ECG pattern is associated with acute pulmonary embolism?

ST elevation in V1–V4
Delta waves in lateral leads
Peaked P waves in lead II
S1Q3T3 pattern (S wave in I, Q wave and T-wave inversion in III) (Correct answer)

Correct answer: S1Q3T3 pattern (S wave in I, Q wave and T-wave inversion in III)

The S1Q3T3 pattern reflects right heart strain from acute PE, though sinus tachycardia is the most common PE ECG finding.

Question 113: Which AHA monitoring category applies to patients who are in the first 48 hours after acute MI?

Class I (monitoring indicated) (Correct answer)
Class III (monitoring not indicated)
Class IV (monitoring contraindicated)
Class II (monitoring of uncertain benefit)

Correct answer: Class I (monitoring indicated)

The AHA designates continuous cardiac monitoring as Class I (clearly indicated) during the first 48 hours after acute MI.

Question 114: An ECG shows a wide complex tachycardia at 180 bpm with AV dissociation. What is the most likely diagnosis?

Ventricular tachycardia (Correct answer)
Atrial flutter with bundle branch block
Supraventricular tachycardia with aberrancy
Accelerated junctional tachycardia

Correct answer: Ventricular tachycardia

AV dissociation (P waves marching through QRS independently) in a wide complex tachycardia is a hallmark of ventricular tachycardia.

Question 115: Which rhythm is characterized by a P wave that follows (rather than precedes) the QRS complex?

Junctional rhythm (Correct answer)
First-degree AV block
Sinus bradycardia
Idioventricular rhythm

Correct answer: Junctional rhythm

In junctional rhythms, the AV node fires and activates the ventricles before (or simultaneously with) retrograde atrial activation, placing the P wave after the QRS.

Question 116: Which lead configuration is most commonly used in a standard 2-channel Holter monitor to maximize arrhythmia and ischemia detection?

V2 and V6
aVR and aVL
Standard leads I and II
Modified V1 and V5 (Correct answer)

Correct answer: Modified V1 and V5

Modified V1 and V5 are the most commonly used channels in 2-channel Holter monitoring because they optimize detection of both arrhythmias and ST-segment changes indicating ischemia.

Question 117: What does the QRS complex represent?

Ventricular repolarization
AV node conduction
Atrial depolarization
Ventricular depolarization (Correct answer)

Correct answer: Ventricular depolarization

The QRS complex represents the rapid depolarization of both ventricles, triggering ventricular contraction and ejection of blood.

Question 118: What is the significance of lead reversal on a 12-lead ECG?

It automatically triggers an alarm
It can mimic pathological conditions and lead to misdiagnosis (Correct answer)
It has no clinical significance
It only affects the heart rate display

Correct answer: It can mimic pathological conditions and lead to misdiagnosis

Lead reversal can produce ECG patterns that mimic pathology such as dextrocardia, lateral MI, or right axis deviation, potentially leading to unnecessary interventions.

Question 119: A QRS complex that is wider than 0.12 seconds most likely indicates:

Accelerated junctional rhythm
Sinus tachycardia
Ventricular conduction abnormality or bundle branch block (Correct answer)
First-degree AV block

Correct answer: Ventricular conduction abnormality or bundle branch block

A QRS duration ≥0.12 seconds indicates delayed intraventricular conduction, typical of bundle branch blocks or ventricular rhythms.

Question 120: What is the normal duration of the QRS complex?

0.06 to 0.10 seconds (Correct answer)
0.20 to 0.30 seconds
0.12 to 0.20 seconds
0.01 to 0.04 seconds

Correct answer: 0.06 to 0.10 seconds

A normal QRS complex lasts 0.06-0.10 seconds (1.5-2.5 small boxes). A QRS wider than 0.12 seconds suggests a bundle branch block or ventricular origin.

NHA Certified EKG Technician (CET)

The NHA CET certification validates competency in performing and interpreting electrocardiograms, including proper patient preparation, ECG acquisition, safety compliance, and basic rhythm analysis for healthcare professionals.

120

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120 min

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