This free CET study guide teaches the patient-care, acquisition, and interpretation knowledge the NHA Certified EKG Technician exam tests, organized to the current CET test plan and its three scored domains.[2] The CET is the credential the NHA awards to the technician who records and recognizes electrocardiograms.
It’s interactive, not a wall of text: every module has built-in checkpoint quizzes, flashcards, and practice questions, so you learn by doing — not just reading. Prefer to study from the job’s perspective rather than the credential’s? Our companion EKG Technician study guide covers the same NHA exam from the hands-on role angle.
What the CET Exam Is
The CET is earned by passing the NHA Certified EKG Technician exam: a 120-item, multiple-choice computer-based test with a 2-hour window.[1] Of the 120 items, 100 are scored and 20 are unscored pretest questions mixed in and indistinguishable. It tests what a competent EKG technician does — identify and prepare the patient safely, acquire a clean 12-lead tracing, troubleshoot artifact, and recognize the rhythm — while staying inside the technician’s .
The single most useful thing to know before you study: the exam mirrors the real testing workflow. Most items ask what a competent technician would do at a given point, and the right answer almost always follows a predictable order — identify and protect the patient, prepare and place electrodes, verify settings, acquire and clean up the tracing, then document and escalate anything dangerous to a licensed provider.
- 1
Verify the order & identify the patient
Confirm the test order, then identify the patient with two identifiers (name and date of birth). Wrong-patient tracings are a safety and HIPAA failure.
- 2
Explain, gain cooperation & position
Explain the painless procedure, answer questions within scope, and position the patient supine with limbs relaxed to minimize muscle (somatic) artifact.
- 3
Prep skin & apply 10 electrodes
Clean, dry, and lightly abrade the sites; apply 4 limb and 6 precordial electrodes by anatomical landmark for a standard 12-lead.
- 4
Verify settings & acquire the tracing
Confirm 25 mm/s paper speed and 10 mm/mV gain, then record all 12 leads, watching the screen for a clean baseline.
- 5
Check quality & resolve artifact
Inspect for wandering baseline, somatic tremor, or 60-cycle interference; re-prep, reposition, or move cables and re-run before accepting the tracing.
- 6
Label, document & report
Confirm all 12 leads recorded, label the strip, enter it in the EMR/EHR, and escalate any life-threatening rhythm to a licensed provider immediately.
One naming note worth keeping straight: “CET” and “EKG technician” describe the same NHA exam— CET is the credential, EKG technician is the job. There are several EKG technician credentials from different bodies (the NHA CET is the most common), so always confirm which exam your program or employer requires before you apply.[1]
CET Exam Snapshot
| Detail | CET / NHA |
|---|---|
| Credential | Certified EKG Technician (awarded by the NHA) |
| Exam used | NHA Certified EKG Technician (CET) examination |
| Questions | 120 items (100 scored + 20 pretest) |
| Time | 2 hours |
| Delivery | Computer-based, multiple-choice |
| Scoring | Scaled score on a 200–500 range; 390 required to pass |
| Result | Pass / Fail, with a per-domain diagnostic breakdown |
| Renewal | Every 2 years with 10 continuing-education (CE) credits |
The NHA CET scores three content domains.[2] Study by weight — EKG Acquisition is by far the largest at 44% of the exam, and the top two domains together make up more than three-quarters of the scored items:
Module 1 · Safety, Compliance & Coordinated Patient Care
One scored domain — 32% of the exam (32 items). Before a single electrode goes on, the technician has to keep the patient and the information safe and work as part of the care team. This domain rewards knowing the rules cold: privacy law, infection control, scope of practice, and clear communication.
1.1 HIPAA, PHI & Scope of Practice
protects a patient’s — any individually identifiable health data, in any form: electronic, paper, or spoken.[3] That means an EKG tracing, a name on a chart, and a hallway comment about a patient are all PHI. The minimum necessary standard limits you to sharing only what a task requires, and you never discuss a patient where others can overhear.
Equally tested is . The EKG technician acquires and recognizes tracings; the technician does not diagnose, interpret results for the patient, or treat.
When a patient asks “Am I having a heart attack?”, the in-scope answer reassures them that the physician will review the tracing — never offers a diagnosis. The technician follows the NHA Code of Ethics and the facility’s policies throughout.
1.2 Infection Control & Workplace Safety
are built on one assumption: treat every patient’s blood and body fluids as potentially infectious, no matter the diagnosis.[5] In practice that means consistent hand hygiene— the single most effective measure for preventing the spread of infection between patients — gloves and other PPE when indicated, safe sharps handling, and cleaning or disinfecting reusable lead wires between patients.
Workplace safety is governed by the (29 CFR 1910.1030), which requires an exposure-control plan, PPE, engineering controls, hepatitis B vaccination, and prompt follow-up after an exposure.[4] If a technician sustains a contaminated needlestick or lancet injury, the first action is to wash the area with soap and water and immediately report the exposureso post-exposure evaluation can begin. Electrical safety matters too — properly grounded, intact equipment protects both patient and technician.
1.3 Communication & Coordinated Patient Care
Coordinated care starts with correctly identifying the patientusing two identifiers (such as name and date of birth) — a wrong-patient tracing is both a safety and a HIPAA failure. The technician then explains the painless procedure to gain cooperation, adapting communication to the patient’s culture, language, developmental level, and any disability, and works alongside the multidisciplinary team. Documentation in the EMR/EHR— patient history, medications, vitals, and the completed EKG — keeps the record accurate and the team coordinated.
The technician also obtains and recognizes abnormal vital signs and the signs of cardiopulmonary compromise— syncope, chest pain, shortness of breath, or abnormal vitals — and knows basic life support. During a stress test the technician helps monitor the patient and supports the response to any adverse reaction. None of this crosses into diagnosis: the technician recognizes the emergency and gets the right help.
Checkpoint · Safety, Compliance & Coordinated Patient Care
Question 1 of 8
Under HIPAA, what type of information is classified as protected health information (PHI)?
Module 2 · EKG Acquisition
One scored domain — 44% of the exam (44 items), the single largest. This is the heart of the CET: getting a clean, accurate 12-lead tracing. You need the cardiac anatomy behind the waveform, exact electrode placement, correct machine settings, and the skill to recognize and resolve artifact before the tracing leaves your hands.
2.1 Cardiac Anatomy & Conduction
Every waveform on the EKG comes from the cardiac conduction pathway. The impulse starts at the — the heart’s natural pacemaker in the right atrium, firing 60–100 times a minute — spreads across the atria (the ), is briefly delayed at the (the ), then races down the , the bundle branches, and the to depolarize the ventricles (the ).
- 1
SA node 60–100/min
The sinoatrial node in the right atrium is the heart's natural pacemaker; it fires the impulse that produces the P wave.
- 2
AV node 40–60/min backup
The atrioventricular node briefly delays the impulse so the atria empty before the ventricles contract — the PR interval.
- 3
Bundle of His
Carries the impulse from the AV node into the interventricular septum, where it splits into the right and left bundle branches.
- 4
Bundle branches
The right and left branches conduct the impulse down each side of the septum toward the ventricular walls.
- 5
Purkinje fibers 20–40/min backup
Spread the impulse rapidly through the ventricular muscle, producing the QRS complex and ventricular contraction.
Two facts pay off repeatedly. First, each lower pacemaker has a slower intrinsic backup rate (AV node 40–60/min, Purkinje 20–40/min), so if the SA node fails a backup can take over. Second, the AV nodal delay is what lets the atria empty into the ventricles before they contract — the timing you measure as the PR interval.
2.2 12-Lead Placement & Machine Settings
A standard uses 10 electrodes to produce 12 leads: 4 limb electrodes and 6 chest electrodes.[6] Placement is by anatomical landmark, and a classic exam trap is confusing an (the sensor on the skin) with a (the calculated view). The precordial landmarks are the most tested: place V1 and V2 at the fourth first, then V4, and fill in V3, V5, and V6 by landmark.
4 limb electrodes
RA
Right arm / forearm
LA
Left arm / forearm
RL
Right leg (neutral/ground)
LL
Left leg / lower leg
6 precordial (chest) electrodes
V1
4th intercostal space, right sternal border
V2
4th intercostal space, left sternal border
V3
Midway between V2 and V4
V4
5th intercostal space, left midclavicular line
V5
Same level as V4, anterior axillary line
V6
Same level as V4 and V5, midaxillary line
Before recording, verify the machine settings. The standard is 25 mm/s and the standard is 10 mm/mV; the mark at the start of the tracing is a rectangular pulse 10 mm tall, confirming 1 mV = 10 mm. At 25 mm/s, each small box is 0.04 s and each large box 0.20 s — the basis for every interval and rate measurement.
Good skin prep (clean, dry, lightly abrade; remove oil and lotion with alcohol) is what makes those signals clean.
2.3 Artifacts, Monitoring & Troubleshooting
An is any signal on the tracing that is not from the heart, and resolving it is a core CET skill. Three patterns recur: a slow-drifting (movement, breathing, or loose/dried electrodes); jagged, erratic (shivering, tension, tremor); and a uniform, thick (nearby electrical equipment or crossed lead wires). Each has a specific fix — re-prep and re-secure, warm and relax the patient, or move equipment and uncross the wires.
Wandering baseline
Cause: Slow drift from breathing, movement, or loose/dried electrodes.
Fix: Re-secure or replace electrodes, re-prep skin, ask the patient to lie still and breathe normally.
Somatic (muscle) tremor
Cause: Erratic, jagged spikes from shivering, tension, or movement (e.g., Parkinson's).
Fix: Warm and relax the patient, reposition limbs on a supported surface, reassure to reduce tension.
AC / 60-cycle interference
Cause: Uniform thick fuzz from nearby electrical equipment or crossed/uncoiled lead wires.
Fix: Unplug or move equipment, separate and uncross lead wires, confirm proper grounding.
Interrupted / broken signal
Cause: A loose connection, broken lead wire, or dried-out electrode gel.
Fix: Check and reattach the affected lead, replace the electrode or cable, and re-run the tracing.
Beyond the resting 12-lead, the technician sets up other acquisitions: a records continuously for 24–48 hours to catch intermittent arrhythmias; a records the EKG during treadmill or bicycle exercise; and provides continuous wireless monitoring of admitted patients. Each has its own electrode setup and patient instructions, and the technician verifies that all leads recorded before accepting the tracing.
Checkpoint · EKG Acquisition
Question 1 of 8
When placing the V1 electrode for a standard 12-lead EKG, the correct anatomical location is the:
Module 3 · EKG Analysis & Interpretation
One scored domain — 24% of the exam (24 items). The technician does not diagnose, but must recognizewhat the tracing shows: measure the waveform and intervals, calculate the rate, identify the rhythm, and — critically — recognize a life-threatening rhythm and get help fast.
3.1 Waveforms, Intervals & Heart Rate
Reading a tracing starts with the P-QRS-T waveform. The is atrial depolarization, the is ventricular depolarization (normally narrow, under 0.12 s), and the is ventricular repolarization. The intervals carry the timing: a normal is 0.12–0.20 s, the is rate-dependent, and the should sit flat — elevation or depression suggests injury or ischemia.
P wave
Atrial depolarization
Upright in lead II; < 0.12 s
PR interval
AV conduction (atria → ventricles)
0.12–0.20 s
QRS complex
Ventricular depolarization
< 0.12 s (narrow)
ST segment
Early ventricular repolarization
Flat / isoelectric (no elevation or depression)
T wave
Ventricular repolarization
Upright, rounded, asymmetric
QT interval
Total ventricular activity
Rate-dependent; ~0.36–0.44 s
Heart-rate calculation is a guaranteed item type. For a regular rhythm, divide 300 by the number of large boxes between two R waves, or 1500 by the number of small boxes for precision. For an irregularrhythm such as atrial fibrillation, count the QRS complexes in a 6-second strip and multiply by 10 — the 6-second method works for both.
Practice the arithmetic until it’s automatic.
3.2 Rhythm Recognition & Critical Findings
Rhythm recognition follows a simple checklist: is it regular or irregular, what is the rate, is there a P wave before every QRS, and is the QRS narrow or wide? A is regular, 60–100/min, with an upright P before each narrow QRS. From there, deviations name the rhythm: (under 60), (over 100), (irregularly irregular, no true P waves), and (sawtooth waves, best seen in II, III, aVF).
The highest-stakes part of this domain is recognizing the life-threatening rhythms and acting at once.[6] , pulseless , , and complete (third-degree) are emergencies.
The technician’s job is to recognize the rhythm, activate the emergency response, and get a licensed provider — not to diagnose or treat. A useful caution: fine ventricular fibrillation can mimic asystole in a single lead, so confirm a “flat line” in a second lead.
- Ventricular fibrillation (VF). Chaotic, quivering baseline with no organized QRS — pulseless. Activate emergency response, start CPR; it is a shockable rhythm.
- Ventricular tachycardia (VT). Fast, wide, regular complexes at 100+/min with no P waves. Pulseless VT is shockable; sustained VT is a medical emergency.
- Asystole. A flat line with no electrical activity — cardiac standstill. Confirm in a second lead (fine VF can mimic it), start CPR; not shockable.
- Third-degree (complete) AV block. P waves and QRS complexes march independently — complete dissociation. A medical emergency that often needs pacing.
- Atrial fibrillation (rapid). Irregularly irregular with no true P waves; a fast ventricular response needs prompt provider attention but is not immediately lethal.
Checkpoint · EKG Analysis & Interpretation
Question 1 of 8
A technician is asked which single waveform on the tracing represents the spread of the impulse across both atria. The correct waveform is the:
How to Use This CET Study Guide
This guide is built to be worked, not just read. Because the NHA CET exam tests applied judgment, the most efficient path to a pass is to learn the material and the order a competent technician acts in:
- Study by weight. EKG Acquisition (44%) is the biggest domain — start there, then Safety/Compliance/Patient Care (32%) and Analysis & Interpretation (24%).
- Master the high-yield staples. 12-lead placement (V1–V6 landmarks), the conduction pathway, paper speed and standardization, artifact troubleshooting, heart-rate calculation, and life-threatening rhythm recognition recur constantly.
- Practice the workflow. Identify and protect the patient, prep and place electrodes, verify settings, acquire and clean the tracing, document, and escalate — the right answer usually fits that flow.
- Check off as you go. Use the Study Guide Contents to mark each section done — it raises your exam-readiness score.
- Take every checkpoint. The end-of-module quizzes show exactly which domains need another pass.
- Then prove it. Send your weak area into the flashcards and a practice test, and read every rationale — that is how the knowledge sticks.
CET Concept Questions
Common clinical concepts candidates search while studying for the NHA Certified EKG Technician (CET) exam — each answered briefly and backed by an official source. Test yourself, then drill them as flashcards.
CET Glossary
The high-yield CET terms in one place — hover any dotted term in the guide, or flip the whole deck here as a self-grading flashcard set.
- 12-lead EKG
- The standard resting EKG that records 12 views of the heart using 10 electrodes — 4 limb and 6 precordial (chest) electrodes.
- 60-cycle interference
- Uniform thick fuzz on the tracing from nearby electrical equipment or crossed lead wires (AC interference).
- artifact
- Any unwanted signal on the tracing that is not from the heart — wandering baseline, muscle (somatic) tremor, or AC (60-cycle) interference.
- asystole
- A flat line with no electrical activity — cardiac standstill; confirm in a second lead before assuming it.
- atrial fibrillation
- An 'irregularly irregular' rhythm with no true P waves — only a chaotic baseline — because the atria quiver instead of contracting.
- atrial flutter
- An atrial rhythm with organized 'sawtooth' flutter waves at about 250–350/min, best seen in leads II, III, and aVF.
- AV block
- A delay or blockage of conduction from the atria to the ventricles, graded first-degree, second-degree (Mobitz I/II), or third-degree (complete).
- AV node
- The atrioventricular node, which delays the impulse so the atria empty before the ventricles contract; backup rate 40–60/min.
- bloodborne pathogens standard
- The OSHA rule (29 CFR 1910.1030) protecting workers from exposure to blood and other potentially infectious materials.
- bradycardia
- A heart rate slower than 60 beats per minute.
- bundle of His
- The fibers carrying the impulse from the AV node into the interventricular septum, where it splits into the bundle branches.
- CET
- Certified EKG Technician — the NHA credential awarded for passing the CET exam, certifying the technician who acquires, troubleshoots, and recognizes electrocardiograms.
- EKG
- Electrocardiogram (also ECG) — a recording of the heart's electrical activity over time, displayed as the P-QRS-T waveform.
- electrode
- An adhesive sensor placed on the skin that detects the heart's electrical signals; ten electrodes are used for a standard 12-lead EKG.
- gain
- The EKG's amplitude setting; at standard gain a 1-millivolt signal produces a 10-millimeter deflection.
- HIPAA
- The Health Insurance Portability and Accountability Act — federal law protecting patients' protected health information (PHI).
- Holter monitor
- A portable EKG worn 24–48 hours (or longer) that continuously records the rhythm during daily activity to catch intermittent arrhythmias.
- hyperkalemia
- A high blood potassium level that classically produces tall, narrow, peaked T waves on the EKG.
- intercostal space
- The gap between two ribs, used as the anatomical landmark for placing the precordial chest electrodes.
- lead
- A specific view of the heart's electrical activity calculated from electrode signals; a standard EKG has 12 leads, not 12 electrodes.
- midaxillary line
- The vertical line down the side of the chest used to locate the V6 electrode at the level of V4 and V5.
- NHA
- National Healthcareer Association — the certifying body that develops and awards the Certified EKG Technician (CET) credential.
- normal sinus rhythm
- A regular rhythm of 60–100/min with an upright P wave before every QRS and normal intervals — the heart's normal pattern.
- P wave
- The first waveform — atrial depolarization (the atria contracting).
- paper speed
- The rate the EKG paper runs; the standard is 25 mm per second, making each small box 0.04 second.
- PHI
- Protected health information — individually identifiable health data that HIPAA requires be kept private and secure.
- PR interval
- The time from the start of the P wave to the start of the QRS, normally 0.12–0.20 seconds; reflects AV conduction.
- precordial leads
- The six chest leads V1–V6 that view the heart in the horizontal plane.
- Purkinje fibers
- The terminal conduction fibers that spread the impulse rapidly through the ventricular muscle, producing the QRS complex.
- PVC
- Premature ventricular contraction — an early, wide, bizarre QRS arising from the ventricles, usually with no preceding P wave.
- QRS complex
- The tall, narrow deflection representing ventricular depolarization; normally less than 0.12 seconds wide.
- QT interval
- The time from the start of the QRS to the end of the T wave; a prolonged QT raises arrhythmia risk.
- SA node
- The sinoatrial node — the heart's natural pacemaker in the right atrium, normally firing 60–100 times per minute.
- scope of practice
- The set of duties an EKG technician is trained and authorized to perform — acquiring and recognizing EKGs, but not diagnosing or treating.
- somatic tremor
- Erratic, jagged spikes on the tracing caused by patient muscle movement, shivering, or tension.
- ST segment
- The flat line between the QRS and the T wave; elevation or depression suggests injury or ischemia.
- standard precautions
- Treating every patient's blood and body fluids as potentially infectious: hand hygiene, gloves, and equipment cleaning.
- standardization
- Calibrating the EKG so a 1-mV signal deflects exactly 10 mm and the paper runs at 25 mm/s, making tracings comparable.
- stress test
- An exercise EKG recorded while the patient walks on a treadmill or pedals a bicycle to assess the heart under exertion.
- T wave
- The rounded wave representing ventricular repolarization (the ventricles recovering).
- tachycardia
- A heart rate faster than 100 beats per minute.
- telemetry
- Continuous wireless EKG monitoring of an admitted patient, with the rhythm displayed at a central station.
- ventricular fibrillation
- A chaotic, quivering baseline with no organized QRS — a life-threatening, shockable rhythm requiring CPR.
- ventricular tachycardia
- A fast, wide-complex rhythm of three or more ventricular beats in a row — a life-threatening emergency.
- wandering baseline
- A slow up-and-down drift of the tracing from movement, breathing, or loose/dried electrodes.
CET Study Guide FAQ
CET stands for Certified EKG Technician. It is a credential developed and awarded by the National Healthcareer Association (NHA) for technicians who acquire, troubleshoot, and recognize electrocardiograms. The CET exam is a computer-based, multiple-choice test covering three content domains — Safety, Compliance & Coordinated Patient Care; EKG Acquisition; and EKG Analysis & Interpretation.
The NHA CET exam has 120 items: 100 scored questions plus 20 unscored pretest items that are mixed in and indistinguishable, with a 2-hour testing window. Only the 100 scored items count toward your result; the pretest items are being evaluated for future exams.
The NHA reports CET scores on a scaled range of 200 to 500, and the passing standard is a scaled score of 390. The scaled score lets the NHA hold the same difficulty across different exam forms, so your result is reported as pass or fail with a scaled number rather than a raw percentage.
Three domains. EKG Acquisition is the largest at 44% (44 scored items) — cardiac anatomy and conduction, 12-lead placement, skin prep, standardization, artifacts, and Holter/stress/telemetry monitoring. Safety, Compliance & Coordinated Patient Care is 32% (32 items) — HIPAA, scope of practice, infection control, communication, and EMR/EHR. EKG Analysis & Interpretation is 24% (24 items) — waveforms, intervals, heart-rate calculation, and rhythm recognition.
To sit for the NHA CET exam you generally need a high school diploma or GED (or be scheduled to earn one within a set window), and you must have either completed an EKG technician training program within the last five years or have relevant work experience such as performing a minimum number of EKGs on live individuals. Verify the current requirements on the NHA application, as they can change.
They cover the same NHA exam — CET is simply the NHA's credential name for an EKG technician. This CET guide leads with the credential and exam mechanics (scoring, eligibility, the three weighted domains) and the clinical knowledge each domain tests. Our companion EKG Technician study guide walks the same material from the role's hands-on perspective. Use whichever framing you searched for; both are free.
NHA certifications are renewed every two years by completing 10 continuing-education (CE) credits before the certification expires. The NHA offers an online CE library to meet the requirement. If a certification lapses, there is a limited window to reinstate it with additional CE and fees — confirm the current renewal policy with the NHA.
Yes — the full guide, the module checkpoints, the glossary, the concept questions, the practice test, and the flashcards are 100% free, with no account required.
References
- 1.National Healthcareer Association (NHA). “Certified EKG Technician (CET) — Certification & Candidate Handbook (test plan).” nhanow.com. ↑
- 2.National Healthcareer Association (NHA). “CET Test Plan — 100 scored / 20 pretest items, three domains.” nhanow.com. ↑
- 3.U.S. Department of Health & Human Services (HHS). “HIPAA for Professionals — Privacy Rule.” hhs.gov. ↑
- 4.Occupational Safety and Health Administration (OSHA). “Bloodborne Pathogens Standard (29 CFR 1910.1030).” osha.gov. ↑
- 5.Centers for Disease Control and Prevention (CDC). “Standard Precautions for All Patient Care.” cdc.gov. ↑
- 6.National Institutes of Health / National Library of Medicine. “StatPearls & MedlinePlus (ECG, conduction, lead placement, arrhythmias).” ncbi.nlm.nih.gov. ↑
- 100.National Institutes of Health / National Library of Medicine (StatPearls). “EKG Lead Placement (StatPearls).” ncbi.nlm.nih.gov, accessed 20 June 2026. ↑
- 101.MedlinePlus (U.S. National Library of Medicine). “Electrocardiogram (ECG).” medlineplus.gov, accessed 20 June 2026. ↑
- 102.National Institutes of Health / National Library of Medicine (StatPearls). “Arrhythmias and life-threatening rhythms (StatPearls).” ncbi.nlm.nih.gov, accessed 20 June 2026. ↑
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