FREE EKG Technician Study Guide 2026: A Complete NHA CET Walkthrough

This free EKG Technician study guide walks through the highest-yield content the NHA Certified EKG Technician (CET) exam tests, organized by the three domains of the official NHA test plan — EKG Acquisition, Safety/Compliance/Coordinated Patient Care, and EKG Analysis & Interpretation.^[1]

It is interactive, not a wall of text: every domain has worked clinical scenarios, lead-placement and rhythm tables, labeled diagrams, and built-in flashcards, taught the way the CET is actually tested — the skills of accurate 12-lead placement, artifact troubleshooting, and recognizing the rhythms and intervals on the tracing.

Read it domain by domain, then round out your prep with our practice questions and flashcards. The CET credential is awarded by the NHA to candidates who complete an EKG training program (or have hands-on EKG experience) and pass the exam.

EKG Technician Exam Snapshot

EKG Acquisition is the largest domain at 44% of the scored items — so accurate lead placement, skin prep, standardization, and artifact troubleshooting deserve the most study time. Safety, Compliance & Coordinated Patient Care is 32%, and EKG Analysis & Interpretation is 24%.^[1]

Percentages are each domain’s share of the 100 scored items.^[1] This guide teaches all three domains as three study modules, so the structure matches the NHA test plan exactly.

How the CET Exam Is Built

The CET exam follows the NHA test plan, which groups every scored item into three domains. This guide teaches all three as study modules, so the structure matches the blueprint exactly.^[1]

• EKG Acquisition (44%) — cardiac anatomy and the conduction system, 12-lead electrode and lead placement, skin prep, standardization, artifact troubleshooting, and Holter/stress/telemetry: the core hands-on skill.
• Safety, Compliance & Coordinated Patient Care (32%) — HIPAA and PHI, scope of practice, infection control and OSHA safety, patient identification, communication, and emergencies.
• EKG Analysis & Interpretation (24%) — the P-QRS-T waveform, intervals and segments, rate calculation, and recognizing sinus, atrial, junctional, and ventricular rhythms plus AV blocks.

Everything on the exam connects back to one mission: producing a clean, accurate tracing of the right patient and recognizing when a rhythm needs urgent attention. The CET acquires and recognizes EKGs within a defined scope of practice — the technician does not diagnose or treat.

Safety, Compliance & Patient Care

Safety, Compliance & Coordinated Patient Care is 32% of the scored items.^[1] It is everything around the tracing: protecting patient privacy, staying within your role, preventing infection, identifying the right patient, communicating, and responding to emergencies.

HIPAA & Protected Health Information

HIPAA protects a patient’s protected health information (PHI)— any individually identifiable health data. As an EKG technician you may access and share PHI only on a need-to-know basis for the patient’s care; keep tracings and screens secure, never discuss patients in elevators or hallways, verify a requester’s identity and authorization before releasing information, and never copy patient data onto a personal device.^[4]

Scope of Practice & Professionalism

The CET acquires high-quality tracings, applies leads correctly, recognizes artifacts and basic rhythms, and reports findings — but does not diagnose, interpret for the medical record, or treat. When asked to do something outside your training or facility policy, decline and check with your supervisor rather than work beyond your scope. Recognizing and escalating a dangerous rhythm is in scope; making the diagnosis is not.^[1]

Infection Control & Safety

Standard precautions treat every patient’s blood and body fluids as potentially infectious: perform hand hygiene before and after each patient, wear gloves when contact with fluids is likely, and clean shared equipment and lead wires between patients. Under OSHA’s Bloodborne Pathogens Standard, used sharps go directly into a puncture-proof container and are never recapped by hand.^[5][6]

Patient Care & Communication

Before any EKG, use at least two patient identifiers — typically full name and date of birth — verified against the order and the wristband; never use the room or bed number. Introduce yourself, explain the procedure, provide for privacy and comfort, and gain cooperation (a relaxed patient produces a cleaner tracing). Adapt to the patient: use an interpreter when needed, and accommodate pediatric, geriatric, and anxious patients.^[4]

Electrical Safety & Emergencies

EKG equipment is electrical, so inspect cables for fraying, keep units grounded, and keep electrical devices away from oxygen and water. If a patient shows signs of distress — chest pain, fainting, or an ominous rhythm on the monitor — stay with the patient, call for help, and follow the facility’s emergency response. Recognizing a life-threatening rhythm and escalating quickly is a core part of the role.^[3]

EKG Acquisition

EKG Acquisition is the largest domain at 44% of the scored items.^[1] It is the hands-on heart of the job: knowing the cardiac conduction system, placing the 10 electrodes correctly, prepping skin and standardizing the machine, troubleshooting artifacts, and running Holter, stress, and telemetry studies.

Cardiac Anatomy & Conduction

The heart has four chambers — two atria on top, two ventricles below — and pumps in a coordinated sequence driven by its electrical conduction system. The impulse starts in the SA node (the natural pacemaker, 60–100/min), is delayed at the AV node so the atria can empty, travels down the bundle of His and the bundle branches, and spreads through the Purkinje fibers to make the ventricles contract.^[4] This sequence is exactly what the P, QRS, and T waves record.

12-Lead Placement & Color Codes

A standard 12-lead EKG uses 10 electrodes — 4 limb and 6 precordial (chest) — to produce 12 views. The three limb electrodes form Einthoven’s triangle, which defines limb leads I, II, and III; the fourth limb electrode (right leg) is the ground. Accurate placement is the single most-tested acquisition skill, because a misplaced electrode changes the tracing.^[4]

Skin Prep & Standardization

Good contact starts with good skin prep: the skin should be clean and dry, with hair removed where it blocks an electrode, oils wiped off, and the site lightly abraded so the gel makes firm contact. Then confirm the machine is standardized — a 1-millivolt signal must deflect the trace exactly 10 mm, and the paper must run at 25 mm/s.^[3] Those settings are what make every interval measurable:

At the standard paper speed, $1\ \text{small box} = 0.04\ \text{s}$ and $1\ \text{large box} = 0.20\ \text{s}$, and a full standardization mark is $10\ \text{mm} = 1\ \text{mV}$ tall (two large boxes).

Artifacts & Troubleshooting

An artifact is any signal on the tracing that is not from the heart. Being able to name the artifact and fix its cause is heavily tested. A wandering baseline drifts up and down (movement, breathing, loose electrodes); a somatic (muscle) tremor adds fuzzy spikes (shivering, tension); and AC (60-cycle) interference lays uniform thick fuzz over the trace (nearby electrical equipment or crossed wires).^[4]

Holter, Stress & Telemetry

Beyond the resting 12-lead, the technician supports continuous and exercise monitoring. A Holter monitor records continuously for 24–48 hours (or longer) during daily activity to catch intermittent arrhythmias; the patient keeps a symptom diary.

A stress (exercise) test records the EKG while the patient walks a treadmill or pedals a bicycle, watching for exercise-induced changes. Telemetry is continuous wireless monitoring of an admitted patient, displayed at a central station.^[4]

EKG Analysis & Interpretation

EKG Analysis & Interpretation is 24% of the scored items.^[1] A CET does not diagnose, but must read the waveform components, measure the intervals, calculate rate, and recognize the common — and the dangerous — rhythms so the right ones are escalated quickly.

Waveforms, Intervals & Segments

Every normal beat is a P wave (atrial depolarization), a QRS complex (ventricular depolarization), and a T wave (ventricular repolarization). The key measurements are the PR interval (P start to QRS start), the QRS duration, the QT interval, and the ST segment.^[4]

Calculating Heart Rate

There are three standard ways to find the rate. For a regular rhythm, the 300 method is fastest: $\text{rate} = \dfrac{300}{\text{large boxes between R waves}}$ (memorize 300, 150, 100, 75, 60, 50).

The 1500 method is more precise: $\text{rate} = \dfrac{1500}{\text{small boxes between R waves}}$. For an irregular rhythm, the 6-second method is required: count the QRS complexes in a 6-second strip and multiply by 10.^[4]

Sinus & Atrial Rhythms

Normal sinus rhythm is regular at 60–100/min with an upright P wave before every QRS. Same pattern, different rate: sinus bradycardia (< 60) and sinus tachycardia (> 100). Atrial rhythms arise above the ventricles: a PAC is an early atrial beat; atrial flutter shows sawtooth waves; and atrial fibrillation is irregularly irregular with no true P waves.^[4]

Junctional & Ventricular Rhythms

Junctional rhythms originate at the AV junction, so the P wave is inverted, hidden, or after the QRS. Ventricular rhythms are wide-complex and more dangerous: a PVC is a single early, wide, bizarre QRS; ventricular tachycardia is three or more in a row at a fast rate; and ventricular fibrillation is a chaotic quiver with no organized QRS.^[4]

AV Blocks & Life-Threatening Rhythms

An AV block is a conduction delay between the atria and ventricles. A consistently long PR interval (> 0.20 s) is first-degree; a PR that lengthens until a QRS drops is second-degree Mobitz I (Wenckebach); intermittent dropped QRS without lengthening is Mobitz II; and complete dissociation of P waves and QRS complexes is third-degree (complete) block. Use a consistent 5-step approach to read any strip.^[4]

How to Use This Study Guide

Work through the guide one domain at a time. After each domain, check it off in the contents to raise your exam-readiness score, then drill the same content in our free practice questions and flashcards — active recall and timed practice are what move knowledge into exam-day performance.

• Weight your time by the percentages. EKG Acquisition is 44% of the exam — start there.
• Drill lead placement relentlessly. Accurate 12-lead placement and the V1–V6 positions are the densest, most-tested acquisition content.
• Master the artifacts. Being able to name an artifact by its look and state the fix is high-yield and recurs across the exam.
• Make rate calculation automatic. Memorize 300-150-100-75-60-50 and the 6-second method for irregular rhythms.
• Then prove it. When a domain feels easy, confirm it with our practice questions and flashcards.

Common questions EKG Technician candidates search and get asked — each answered briefly and backed by an official source (NHA, AHA, NIH, OSHA, or CDC). Tap any card to test yourself.

EKG Technician Glossary

Key EKG Technician terms in one place. Hover any dotted term throughout the guide for its definition; the full list is below.

CET

Certified EKG Technician — the NHA credential for the technician who acquires, troubleshoots, and recognizes electrocardiograms in patient-care settings.

NHA

National Healthcareer Association — the certifying body that develops and awards the Certified EKG Technician (CET) credential.

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.

lead

A specific view of the heart's electrical activity calculated from electrode signals; a standard EKG has 12 leads (not 12 electrodes).

12-lead EKG

The standard resting EKG that records 12 views of the heart using 10 electrodes — 4 limb and 6 precordial (chest) electrodes.

precordial leads

The six chest leads V1–V6 that view the heart in the horizontal plane.

Einthoven's triangle

An imaginary inverted triangle formed by the right-arm, left-arm, and left-leg electrodes that defines limb leads I, II, and III.

SA node

The sinoatrial node — the heart's natural pacemaker in the right atrium, normally firing 60–100 times per minute.

AV node

The atrioventricular node, which delays the impulse so the atria empty before the ventricles contract; backup rate 40–60/min.

bundle of His

The fibers carrying the impulse from the AV node into the interventricular septum, where it splits into the bundle branches.

Purkinje fibers

The terminal conduction fibers that spread the impulse rapidly through the ventricular muscle, producing the QRS complex.

P wave

The first waveform — atrial depolarization (the atria contracting).

QRS complex

The tall, narrow deflection representing ventricular depolarization; normally less than 0.12 seconds wide.

T wave

The rounded wave representing ventricular repolarization (the ventricles recovering).

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.

QT interval

The time from the start of the QRS to the end of the T wave; a prolonged QT raises arrhythmia risk.

ST segment

The flat line between the QRS and the T wave; elevation or depression suggests injury or ischemia.

standardization

Calibrating the EKG so a 1-mV signal deflects exactly 10 mm and the paper runs at 25 mm/s, making tracings comparable.

artifact

Any unwanted signal on the tracing that is not from the heart — wandering baseline, muscle tremor, or AC (60-cycle) interference.

wandering baseline

A slow up-and-down drift of the tracing from movement, breathing, or loose/dried electrodes.

60-cycle interference

Uniform thick fuzz on the tracing from nearby electrical equipment or crossed lead wires (AC interference).

Holter monitor

A portable EKG worn 24–48 hours (or longer) that continuously records the rhythm during daily activity to catch intermittent arrhythmias.

stress test

An exercise EKG recorded while the patient walks on a treadmill or pedals a bicycle to assess the heart under exertion.

telemetry

Continuous wireless EKG monitoring of an admitted patient, with the rhythm displayed at a central station.

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.

bradycardia

A heart rate slower than 60 beats per minute.

tachycardia

A heart rate faster than 100 beats per minute.

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.

PVC

Premature ventricular contraction — an early, wide, bizarre QRS arising from the ventricles, usually with no preceding P wave.

ventricular tachycardia

A fast, wide-complex rhythm of three or more ventricular beats in a row — a life-threatening emergency.

ventricular fibrillation

A chaotic, quivering baseline with no organized QRS — a life-threatening, shockable rhythm requiring CPR.

asystole

A flat line with no electrical activity — cardiac standstill.

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).

HIPAA

The Health Insurance Portability and Accountability Act — federal law protecting patients' protected health information (PHI).

PHI

Protected health information — individually identifiable health data that HIPAA requires be kept private and secure.

standard precautions

Treating every patient's blood and body fluids as potentially infectious: hand hygiene, gloves, and equipment cleaning.

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.

EKG Technician Study Guide FAQ

References

1. 1.National Healthcareer Association (NHA). “Certified EKG Technician (CET) Certification & Candidate Handbook (test plan).” NHA. ↑
2. 2.National Healthcareer Association (NHA). “Stay Certified — CET Recertification (10 CE credits / 2 years).” NHA. ↑
3. 3.American Heart Association (AHA). “Recommendations for the Standardization and Interpretation of the Electrocardiogram.” AHA. ↑
4. 4.National Institutes of Health / National Library of Medicine. “StatPearls & MedlinePlus (ECG, cardiac anatomy, arrhythmias, lead placement).” NIH/NLM. ↑
5. 5.Occupational Safety and Health Administration (OSHA). “Bloodborne Pathogens Standard (29 CFR 1910.1030).” OSHA. ↑
6. 6.Centers for Disease Control and Prevention (CDC). “Standard Precautions & Infection Control in Healthcare.” CDC. ↑

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