Chapter 25Medical Testing

Health Care Science Technology

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Chapter 252 Copyright © The McGraw-Hill Companies, Inc.

Objectives

Describe the role and responsibilities of an electrocardiography technician.

Explain the role and responsibilities of a cardiovascular technologist.

Identify two or more cardiovascular diagnostic tests.

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Objectives (cont.)

Contrast the roles and responsibilities of the electroencephalography (EEG) technologist and the electroneurodiagnostic technologist.

Explain the purpose of an electroencephalogram.

Successfully complete 1 medical testing procedure.

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Careers in Medical Testing 25-1

Electrocardiography Technician Cardiovascular Technologist EEG and END Technologists

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Careers in Medical Testing

Career opportunities are excellent, including the four most common occupations:– Electrocardiography (ECG) technician.– Cardiovascular technologist.– Electroencephalography (EEG)

technologist.– Electroneurodiagnostic (END)

technologist.

Chapter 256 Copyright © The McGraw-Hill Companies, Inc.

Electrocardiography Technician

Uses an electrocardiograph to record the electrical activity of the heart as a tracing.

Electrocardiograms help diagnose and evaluate cardiovascular disease.

Determines if the tracing is accurate and prepares a report for the physician.

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Electrocardiography Technician (cont.)

Job Responsibilities– Perform a safe and

accurate ECG.– ECG monitor

technicians evaluate the electrical tracings on a monitor.

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Electrocardiography Technician (cont.)

Exercise Electrocardiography– Also known as stress test or treadmill test.– Job responsibilities

Provide client safety.Provide instructions to client.Monitor the client by taking blood pressure.Observe for pain, discomfort, fatigue, or difficulty

breathing.Apply and remove electrodes.

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Electrocardiography Technician (cont.)

Ambulatory Monitoring– Tracings are recorded on a

client who is ambulatory. Often a Holter monitor is used.

– Job responsibilities Apply and remove the

ambulatory monitor. Provide client education. Ensure results are placed in the

client’s chart. Maintain the equipment.

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Cardiovascular Technologist

May need up to 4 years of education and training.

Works directly with cardiologists in clinics, hospitals, physician’s offices, medical centers, and mobile diagnostic units.

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Cardiovascular Technologist (cont.)

Job Responsibilities– May assist physicians with heart

surgery, implantation of pacemakers, and invasive tests such as angioplasty and cardiac catheterization.

– Some specialize in performing ultrasound on the heart and blood vessels in the test called an echocardiogram.

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Cardiovascular Technologist (cont.)

Cardiovascular Testing– A cardiovascular technician needs:

A thorough understanding of the anatomy and physiology of the cardiovascular system.

An ability to work with computers and other technical equipment.

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Cardiovascular Technologist (cont.)

Cardiovascular Testing (cont.)

– Cardiac CatheterizationThis test looks at the structures of the

heart.A small tube is threaded through the

client’s blood vessels to the heart, where pressure is measured and dye is injected.

Chapter 2514 Copyright © The McGraw-Hill Companies, Inc.

Cardiovascular Technologist (cont.)

Cardiovascular Testing (cont.)

– Balloon angioplasty A catheter with a

balloon on its end is inserted into a blood vessel; then the balloon is inflated to expand the blood vessel.

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Cardiovascular Technologist (cont.)

Job Responsibilities– Review and record the client’s history.– Perform diagnostic tests.– Monitor heart rate, blood pressure, and

ECG.– Inform the physician if something appears

wrong.– Use discretion and judgment when

performing duties.

Chapter 2516 Copyright © The McGraw-Hill Companies, Inc.

EEG and END Technologists

The title END is more commonly used, as it most accurately describes the occupation.

Other important terms are:– Electroencephalography – recording

the electrical activity in the brain. – Electroneurodiagnostic – evaluating

the electrical activity of the nervous system.

Chapter 2517 Copyright © The McGraw-Hill Companies, Inc.

EEG and END Technologists (cont.)

Job Responsibilities– Perform tests that evaluate the spinal cord,

the nervous system, and sleep.– Usually employed in:

Acute care hospitals. Neurologists’ offices. Some ambulatory care facilities. Newborn nurseries. Sleep study laboratories. Operating rooms. Epilepsy research centers.

Chapter 2518 Copyright © The McGraw-Hill Companies, Inc.

EEG and END Technologists (cont.)

The electroencephalogram– Records the electrical impulses of the brain,

producing a record called the electroencephalogram.

– The END technologist obtains the client’s medical history, then applies electrodes to the head.

– The END technologist corrects errors on the tracing that are caused by interference during the EEG.

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Section 25-1Apply Your Knowledge

List some invasive procedures the cardiovascular technologist might help perform.

Answer:

Angioplasty, cardiac catheterization, heart surgery, and implantation of pacemakers.

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Medical Testing Procedures 25-2

Recording an ElectrocardiogramAnatomy and Physiology of the

HeartBackground for Recording an

ECGTwelve-Lead ECGECG MachinesECG Machine Controls

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Recording an Electrocardiogram

An electrocardiogram (ECG tracing):– Determines how well the heart is pumping and

contracting.– Checks for problems with the flow of electricity

through the heart.– Diagnoses changes in the heart rhythm.– Checks for abnormal heart changes before surgery.– Assists in evaluating a person’s health after age 40.– Monitors or evaluates individuals with heart

conditions.

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Anatomy and Physiology of the Heart

Sinoatrial (SA) node. Atrioventricular (AV)

node. Bundle of His (AV

bundle). Bundle branches. Purkinje fibers

(network).

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Background for Recording an ECG

The technician must understand the heart’s electrical conduction system.

Each contraction of the heart muscle is controlled by electrical impulses.

The pattern of current is recorded by the ECG machine.

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Background for Recording an ECG (cont.)

The ECG Waveform– The deflections on a tracing rise

above or fall below a straight line.

– This line is known as an isoelectric line, or baseline.

– Positive deflections go up, negative ones go down.

– Each wave represents specific activity in the heart.

Chapter 2525 Copyright © The McGraw-Hill Companies, Inc.

Twelve-Lead ECG

Gives a recording of the electrical activity within the heart.

Attaching the leads and electrodes:– Six leads are attached to the chest

electrodes.– Four leads are attached to electrodes on

the arms and legs.– The 10 lead wires produce 12 different

lead circuits.

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Twelve-Lead ECG (cont.)

Working with Electrodes– Reusable electrodes – plates and

bulbs.– Disposable electrodes – used to

reduce possible contamination.

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Twelve-Lead ECG (cont.)

Proper Handling and Storage– Keep unused electrodes in a sealed

plastic bag.– Check the expiration date.– Ensure the gel has not dried.– Always check electrodes before you

use them.

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ECG Machines

Single-Channel ECG – monitors 12 leads individually.

Multichannel ECG – produces all 12 leads by recording 3 leads at once.

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ECG Machines (cont.)

Other Types of ECG Machines– Some perform functions such as

computerized measurement and analysis, storage, and communication.

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ECG Machine Controls

Speed.Gain.Artifact filter.Computerized controls.Standardizing with the stylus.Lead selector.

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Section 25-2Apply Your Knowledge

How many wires are used in a 12-lead ECG?

Answer: 10.

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Procedures in Student Text

25A Recording an Electrocardiogram

Chapter 2533 Copyright © The McGraw-Hill Companies, Inc.

Chapter 25 Credits

Slide 6 Geoff Butler

Slide 7 Geoff Butler

Slide 9 Geoff Butler

Slide 10 Chip Henderson/Index Stock Imagery

Slide 26 Geoff Butler

Slide 28 Geoff Butler