- CET
- Certified EKG Technician — the NHA credential awarded for passing the CET exam, certifying the technician who acquires, troubleshoots, and recognizes electrocardiograms.
- NHA
- National Healthcareer Association — the certifying body that develops and awards the Certified EKG Technician (CET) credential.
- Scope of practice (EKG technician)
- Acquiring and recognizing EKGs — preparing the patient, placing electrodes, running the machine, and reporting findings; never diagnosing, interpreting for the patient, or treating.
- HIPAA
- The Health Insurance Portability and Accountability Act — the federal law protecting patients' protected health information (PHI).
- Protected health information (PHI)
- Any individually identifiable health information a covered entity holds or transmits — electronic, paper, or spoken — including names, dates, and EKG results.
- Minimum necessary standard
- The HIPAA principle that you share only the protected health information actually needed for a given task.
- Covered entity
- A health-care provider, health plan, or clearinghouse bound by HIPAA to protect patient information.
- NHA Code of Ethics
- The professional standards NHA-certified technicians follow — confidentiality, integrity, respect, and staying within scope of practice.
- Standard (universal) precautions
- Treating every patient's blood and body fluids as potentially infectious — hand hygiene, gloves/PPE, safe sharps handling, and equipment disinfection.
- Hand hygiene
- Hand washing or sanitizing — the single most effective measure for preventing the spread of infection between patients.
- OSHA Bloodborne Pathogens Standard
- 29 CFR 1910.1030 — the OSHA rule protecting workers from exposure to blood and other potentially infectious materials, requiring PPE and an exposure-control plan.
- Personal protective equipment (PPE)
- Gloves, gowns, masks, and eye protection worn to create a barrier against infectious materials.
- Needlestick / sharps injury — first step
- Wash the area with soap and water and immediately report the exposure so post-exposure evaluation can begin.
- Hepatitis B vaccination
- An immunization offered to health-care workers under the OSHA Bloodborne Pathogens Standard to protect against hepatitis B exposure.
- Disinfecting reusable lead wires
- Cleaning lead wires that contact a patient's skin between patients, per facility policy, as a standard-precaution measure.
- Two patient identifiers
- Using two unique identifiers (e.g., name and date of birth) to confirm the right patient before testing — preventing wrong-patient tracings.
- EMR / EHR
- Electronic medical / health record — the digital chart where the technician documents patient history, medications, vitals, and the completed EKG.
- Vital signs
- Temperature, pulse, respiration, blood pressure, and oxygen saturation — measured and recognized as normal or abnormal across the lifespan.
- Cardiopulmonary compromise
- Signs of failing heart or lung function — syncope, chest pain, shortness of breath, or abnormal vitals — that the technician recognizes and escalates.
- Syncope
- A transient loss of consciousness (fainting), a sign of possible cardiopulmonary compromise during cardiac testing.
- Basic life support (BLS)
- Foundational emergency care — recognizing arrest, calling for help, CPR, and using an AED — that an EKG technician is expected to know.
- CPR
- Cardiopulmonary resuscitation — chest compressions and rescue breaths to maintain circulation during cardiac arrest.
- Stress test monitoring (technician role)
- Assisting and watching the patient during an exercise EKG for adverse reactions — chest pain, shortness of breath, abnormal vitals — and supporting the response.
- Communication barriers
- Factors such as culture, language, religion, developmental level, gender, and disability that the technician adapts to when communicating with patients.
- Multidisciplinary health care team
- The physicians, nurses, and other professionals the EKG technician coordinates with to deliver patient care.
- Patient response within scope
- When asked 'Is something wrong with my heart?', reassure that the physician will review the tracing — never offer a diagnosis.
- Electrical safety
- Using properly grounded, intact equipment and inspecting cords to protect both patient and technician from electrical hazards.
- Electrocardiogram (EKG/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 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 (views), 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.
- Limb electrodes
- The four electrodes placed on the arms and legs (RA, LA, RL, LL) that create the limb leads.
- Precordial leads
- The six chest leads V1–V6 that view the heart in the horizontal plane.
- V1 placement
- Fourth intercostal space at the right sternal border.
- V2 placement
- Fourth intercostal space at the left sternal border.
- V3 placement
- Midway between V2 and V4.
- V4 placement
- Fifth intercostal space at the left midclavicular line.
- V5 placement
- Same horizontal level as V4, at the anterior axillary line.
- V6 placement
- Same horizontal level as V4 and V5, at the midaxillary line.
- Intercostal space
- The gap between two ribs, used as the anatomical landmark for placing the precordial chest electrodes.
- Precordial placement order
- Place V1 and V2 at the 4th intercostal space first, then V4, then fill in V3, V5, and V6 by landmark.
- Limb electrode placement
- On the fleshy parts of the lower arms/wrists and lower legs, avoiding bony prominences for a clean signal.
- Skin preparation
- Cleaning, drying, and lightly abrading electrode sites — removing oil, lotion, sweat, and dead skin — to ensure good electrode contact.
- Paper speed
- The rate the EKG paper runs; the standard is 25 mm per second, making each small box 0.04 second.
- Gain
- The EKG's amplitude setting; at standard gain a 1-millivolt signal produces a 10-millimeter deflection.
- Standardization mark
- The rectangular calibration pulse at the start of a tracing, normally 10 mm tall, confirming that 1 mV equals 10 mm.
- Small box (EKG paper)
- At 25 mm/s, a small box is 0.04 second wide; vertically it represents 0.1 mV.
- Large box (EKG paper)
- Five small boxes — 0.20 second wide at 25 mm/s; used in the 300 method for heart rate.
- 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.
- Bundle branches
- The right and left branches that conduct the impulse down each side of the septum toward the ventricular walls.
- Purkinje fibers
- The terminal conduction fibers that spread the impulse rapidly through the ventricular muscle, producing the QRS complex.
- Cardiac conduction pathway
- SA node → AV node → bundle of His → bundle branches → Purkinje fibers — the route of each electrical impulse through the heart.
- Intrinsic pacemaker rates
- SA node 60–100/min, AV node 40–60/min, Purkinje fibers 20–40/min — slower backups if the site above fails.
- Depolarization
- The electrical activation of cardiac muscle that causes contraction; produces the P wave (atria) and QRS complex (ventricles).
- Repolarization
- The electrical recovery of cardiac muscle after contraction; produces the T wave (ventricles).
- Artifact
- Any unwanted signal on the tracing that is not from the heart — wandering baseline, somatic tremor, or AC interference.
- Wandering baseline
- A slow up-and-down drift of the tracing caused by movement, breathing, or loose/dried electrodes.
- Somatic tremor
- Erratic, jagged spikes on the tracing caused by patient muscle movement, shivering, or tension.
- 60-cycle (AC) interference
- Uniform thick fuzz on the tracing from nearby electrical equipment or crossed lead wires — an AC interference artifact.
- Fix for AC interference
- Unplug or move nearby electrical equipment, separate and uncross the lead wires, and confirm proper grounding.
- Fix for wandering baseline
- Re-prep the skin, re-secure or replace loose/dried electrodes, and ask the patient to lie still and breathe normally.
- Fix for somatic tremor
- Warm and relax the patient, support the limbs on a flat surface, and reassure them to reduce muscle tension.
- Holter monitor
- A portable EKG worn 24–48 hours (or longer) that continuously records the rhythm during daily activity to catch intermittent arrhythmias.
- Event monitor
- An ambulatory monitor the patient activates when symptoms occur, recording the EKG around that event.
- 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.
- Target heart rate
- A percentage of the age-predicted maximum heart rate (220 minus age) used to guide exercise stress testing.
- Right-sided EKG
- A modified placement (e.g., V4R) used to assess the right ventricle when a right-sided infarct is suspected.
- Special-population positioning
- Adapting electrode placement for amputees, late-term pregnancy, respiratory issues, or pediatric patients while preserving accuracy.
- Lead reversal
- An electrode placement error (e.g., swapping arm electrodes) that produces a falsely abnormal tracing and must be corrected and re-run.
- Verifying a complete tracing
- Confirming that all 12 leads recorded, the calibration mark is present, and the waveforms are clearly readable before documenting.
- Mounting an EKG strip
- Placing the completed rhythm strip in the patient's chart or record so the provider can review it.
- P wave
- The first waveform — atrial depolarization (the atria contracting); normally upright in lead II.
- QRS complex
- The tall, narrow deflection representing ventricular depolarization; normally less than 0.12 second 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 second; reflects AV conduction.
- QRS duration
- The width of the QRS complex; normally under 0.12 second. A wide QRS suggests abnormal ventricular 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.
- Q wave
- The first downward deflection of the QRS complex before any upward wave.
- R wave
- The first upward (positive) deflection of the QRS complex.
- S wave
- The downward deflection that follows the R wave in the QRS complex.
- Isoelectric line
- The flat baseline of the tracing representing no net electrical activity; ST segments are measured against it.
- 300 method (heart rate)
- For a regular rhythm, divide 300 by the number of large boxes between two R waves to estimate the heart rate.
- 1500 method (heart rate)
- For a regular rhythm, divide 1500 by the number of small boxes between two R waves for a precise heart rate.
- 6-second method (heart rate)
- Count the QRS complexes in a 6-second strip and multiply by 10 — works for both regular and irregular rhythms.
- R-R interval
- The distance between two consecutive R waves, used to judge rhythm regularity and calculate heart rate.
- Normal sinus rhythm
- A regular rhythm of 60–100/min with an upright P wave before every narrow QRS and normal intervals.
- Sinus bradycardia
- A sinus rhythm slower than 60 beats per minute, with normal P waves and intervals.
- Sinus tachycardia
- A sinus rhythm faster than 100 beats per minute, with an upright P wave before each narrow QRS.
- 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, best seen in leads II, III, and aVF.
- Premature atrial contraction (PAC)
- An early beat originating in the atria, with an abnormal P wave arriving sooner than expected.
- Premature ventricular contraction (PVC)
- An early, wide, bizarre QRS arising from the ventricles, usually with no preceding P wave.
- Junctional rhythm
- A rhythm originating at the AV junction, often with absent, inverted, or hidden P waves and a rate near 40–60/min.
- 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; confirm in a second lead before assuming it.
- First-degree AV block
- A consistently prolonged PR interval (over 0.20 s) with every P wave still conducting to a QRS.
- Second-degree AV block, Mobitz I (Wenckebach)
- Progressive PR-interval lengthening until a QRS is dropped, then the cycle repeats.
- Second-degree AV block, Mobitz II
- Intermittently dropped QRS complexes with a constant PR interval; more dangerous than Mobitz I.
- Third-degree (complete) AV block
- Complete dissociation of P waves and QRS complexes, which march independently — a medical emergency.
- Bundle branch block
- Delayed conduction in a bundle branch that widens the QRS because one ventricle is activated late by slow cell-to-cell spread.
- Pacemaker spike
- A sharp, narrow vertical deflection on the tracing marking each electronic pacemaker discharge.
- Ischemia
- Reduced blood flow to the heart muscle, often shown as ST-segment depression or T-wave inversion.
- Injury (acute)
- Active myocardial injury classically shown as ST-segment elevation on the tracing.
- Infarction
- Death of heart muscle from prolonged ischemia, often producing pathologic Q waves over time.
- Hyperkalemia
- A high blood potassium level that classically produces tall, narrow, peaked T waves on the EKG.
- Hypokalemia
- A low blood potassium level that can flatten T waves and produce U waves on the EKG.
- U wave
- A small deflection sometimes following the T wave, associated with hypokalemia.
- Regular vs. irregular rhythm
- Regular rhythms have constant R-R intervals; irregular rhythms vary — judged by comparing R-R distances across the strip.
- Rhythm analysis checklist
- Assess regularity, rate, a P wave before each QRS, and QRS width to systematically name the rhythm.
- Life-threatening rhythm — technician action
- Recognize the rhythm, activate the emergency response, and get a licensed provider — do not diagnose or treat.
- Fine VF mimicking asystole
- Fine ventricular fibrillation can look like a flat line in one lead; confirm a suspected asystole in a second lead.
- Shockable rhythms
- Ventricular fibrillation and pulseless ventricular tachycardia — rhythms treated with defibrillation and CPR.
- Sawtooth waves
- The regular flutter waves of atrial flutter, best identified in the inferior leads II, III, and aVF.