Chapter 25
Medical Testing
Health Care
Science
Technology
Copyright © The McGraw-Hill Companies, Inc.
Objectives
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2
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.
Copyright © The McGraw-Hill Companies, Inc.
Chapter 25
Objectives (cont.)
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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.
Copyright © The McGraw-Hill Companies, Inc.
Chapter 25
Careers in Medical Testing 25-1
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Electrocardiography Technician
Cardiovascular Technologist
EEG and END Technologists
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Chapter 25
Careers in Medical Testing

Career opportunities are excellent,
including the four most common
occupations:
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Electrocardiography (ECG) technician.
Cardiovascular technologist.
Electroencephalography (EEG)
technologist.
Electroneurodiagnostic (END)
technologist.
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Chapter 25
Electrocardiography Technician
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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.
Copyright © The McGraw-Hill Companies, Inc.
Chapter 25
Electrocardiography Technician
(cont.)
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Job Responsibilities
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Perform a safe and
accurate ECG.
ECG monitor
technicians evaluate
the electrical tracings
on a monitor.
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Chapter 25
Electrocardiography Technician
(cont.)

Exercise Electrocardiography
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Also known as stress test or treadmill test.
Job responsibilities
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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.
Copyright © The McGraw-Hill Companies, Inc.
Chapter 25
Electrocardiography Technician
(cont.)

Ambulatory Monitoring
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Tracings are recorded on a
client who is ambulatory. Often
a Holter monitor is used.
Job responsibilities
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Apply and remove the
ambulatory monitor.
Provide client education.
Ensure results are placed in the
client’s chart.
Maintain the equipment.
Copyright © The McGraw-Hill Companies, Inc.
Chapter 25
Cardiovascular Technologist
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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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Chapter 25
Cardiovascular Technologist (cont.)
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Job Responsibilities
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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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Chapter 25
Cardiovascular Technologist (cont.)
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Cardiovascular Testing
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A cardiovascular technician needs:
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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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Chapter 25
Cardiovascular Technologist (cont.)
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Cardiovascular Testing (cont.)
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Cardiac Catheterization
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This 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.
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Chapter 25
Cardiovascular Technologist (cont.)
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Cardiovascular
Testing (cont.)
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Balloon angioplasty
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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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Chapter 25
Cardiovascular Technologist (cont.)
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Job Responsibilities
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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.
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Chapter 25
EEG and END Technologists
The title END is more commonly
used, as it most accurately
describes the occupation.
 Other important terms are:
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Electroencephalography – recording
the electrical activity in the brain.
Electroneurodiagnostic – evaluating
the electrical activity of the nervous
system.
Copyright © The McGraw-Hill Companies, Inc.
Chapter 25
EEG and END Technologists (cont.)
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Job Responsibilities
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Perform tests that evaluate the spinal cord,
the nervous system, and sleep.
Usually employed in:
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Acute care hospitals.
Neurologists’ offices.
Some ambulatory care facilities.
Newborn nurseries.
Sleep study laboratories.
Operating rooms.
Epilepsy research centers.
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Chapter 25
EEG and END Technologists (cont.)

The electroencephalogram
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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.
Copyright © The McGraw-Hill Companies, Inc.
Chapter 25
Section 25-1
Apply 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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Chapter 25
Medical Testing Procedures 25-2
Recording an Electrocardiogram
 Anatomy and Physiology of the
Heart
 Background for Recording an
ECG
 Twelve-Lead ECG
 ECG Machines
 ECG Machine Controls
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Copyright © The McGraw-Hill Companies, Inc.
Chapter 25
Recording an Electrocardiogram

An electrocardiogram (ECG tracing):
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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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Chapter 25
Anatomy and
Physiology of the Heart
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Sinoatrial (SA) node.
Atrioventricular (AV)
node.
Bundle of His (AV
bundle).
Bundle branches.
Purkinje fibers
(network).
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Chapter 25
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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Copyright © The McGraw-Hill Companies, Inc.
Chapter 25
Background for Recording an ECG
(cont.)
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The ECG Waveform
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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.
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Chapter 25
Twelve-Lead ECG
Gives a recording of the electrical
activity within the heart.
 Attaching the leads and electrodes:
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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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Chapter 25
Twelve-Lead ECG (cont.)
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Working with Electrodes
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Reusable electrodes – plates and
bulbs.
Disposable electrodes – used to
reduce possible contamination.
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Chapter 25
Twelve-Lead ECG (cont.)
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Proper Handling and Storage
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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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Chapter 25
ECG Machines
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Single-Channel ECG –
monitors 12 leads
individually.
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Multichannel ECG –
produces all 12 leads
by recording 3 leads
at once.
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Chapter 25
ECG Machines (cont.)
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Other Types of ECG Machines
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29
Some perform functions such as
computerized measurement and
analysis, storage, and
communication.
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Chapter 25
ECG Machine Controls
Speed.
 Gain.
 Artifact filter.
 Computerized controls.
 Standardizing with the stylus.
 Lead selector.
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Chapter 25
Section 25-2
Apply Your Knowledge
How many wires are used in a
12-lead ECG?
Answer: 10.
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Chapter 25
Procedures in Student Text
25A
32
Recording an
Electrocardiogram
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Chapter 25
Chapter 25 Credits
Slide 6
Slide 7
Slide 9
Slide 10
Slide 26
Slide 28
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Geoff Butler
Geoff Butler
Geoff Butler
Chip Henderson/Index Stock
Imagery
Geoff Butler
Geoff Butler
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Chapter 25