CHAPTER © 2014 by McGraw-Hill Education. This is proprietary material solely for authorized instructor use. Not authorized for sale or distribution in.

CHAPTER

© 2014 by McGraw-Hill Education. This is proprietary material solely for authorized instructor use. Not authorized for sale or distribution in any manner. This document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a

website, in whole or part.

49Electrocardiography

and Pulmonary Function Testing



49-2

49.1 Discuss the medical assistant's role in electrocardiography and pulmonary function testing.

49.2 Explain the basic principles of electrocardiography and how it relates to the conduction system of the heart.

49.3 Identify the components of an electrocardiograph and what each does.

49.4 Carry out the steps necessary to obtain an ECG.

Learning Outcomes



49-3

49.5 Summarize exercise electrocardiography and echocardiography.

49.6 Explain the procedure of Holter monitoring.

49.7 Carry out the various types of pulmonary function tests.

49.8 Describe the procedure for performing pulse oximetry testing.

Learning Outcomes



49-4

Introduction

• Cardiac testing– Electrocardiogram– Holter monitoring – Stress testing

• Respiratory testing – pulmonary function testing



49-5

The Medical Assistant’s Role in Electrocardiography and Pulmonary Function Testing

• Medical assistant may perform – Electrocardiography

– Pulmonary function tests (PFTs)

– Diagnostic reasons

– Part of general exam



49-6

Basic Principles of Electrocardiography

• Heartbeats produce electrical current

• Resting cardiac cell – polarized

• Depolarization – Occurs when cell loses polarity– Electrical impulse initiates contraction– Impulse detected by electrodes



49-7

Basic Principles of Electrocardiography

• Depolarization

• Repolarization – electrical recovery

• Polarizedstate

• Cardiac cycle – sequence of contraction and relaxation



49-8

The Basic Pattern of the Electrocardiogram

• Electrocardiogram (ECG) produces the electrocardiograph

– Tracing of waves and lines produced by the cardiac cycle

– Deflections • Peaks and valleys

• Sections labeled PQRSTU To example



49-9

Apply Your Knowledge

1. What two procedures might the medical assistant preform?

ANSWER: Electrocardiography and pulmonary function testing.

2. What is the term for the depolarization, repolarization, and polarized state sequence?

ANSWER: The cardiac cycle.



49-10

The Electrocardiograph

• Impulse is detected by electrodes

• Transmitted by insulated wires

• Amplified by the electrocardiograph machine

• Stylus – records the movement

• Leads – views of electrical activity



49-11

Types of Electrocardiographs

• Standard – 12-lead electrograph

• Single-channel

• Multichannel



49-12

Electrodes and Electrolyte Products

• Electrolyte is needed to enhance transmission of electric current

• Electrodes are placed– One on each arm– One on each leg– Six on chest



49-13

Leads

• Limb leads

– Three standard leads

• Bipolar

• Designation – I, II, III

– Three augmented views• Unipolar • Amplified • Designation – AVF, AVR, AVL



49-14

Leads

• Precordial leads– Unipolar

– Designated V1 through V6



49-15

ECG Paper

• Standardized pattern of small and large squares

• Horizontal axis – time in seconds

• Vertical axis – voltage (mV)



49-16

The Electrocardiograph Controls

• Standardization control

• Speed selector

• Sensitivity control

• Lead selector



49-17

The Electrocardiograph Controls

• Centering control

• Line control

• On/Off switch



49-18


Matching:

___ Adjusts position of stylus A. Vertical axis

___ Adjusts height of tracing B. Sensitivity control

___ Adjusts darkness of tracing C. Precordial leads

___ Measures strength of impulse D. Horizontal axis

___ Measures time E. Limb leads

___ AVF, AVR, AVL F. Amplification

___ V1 through V6 G. Centering control

___ Increases signal H. Line control

ANSWER:

H

G

F

E

D

C

B

A

Superbly Matched!



49-19

Performing an ECG

• Proper technique essential

• Preparing the room and equipment– Turn off other electrical equipment

– Quiet room, comfortable temperature

– Check machine• Warm up• Adequate paper



49-20

Performing an ECG (cont.)

• Preparing the patient

– Introduce yourself

– Explain the procedure

– Answer questions

– Ensure patient comfort

– Perform ECG procedure



49-21

Applying the Electrodes and the Connecting Wires

• Electrodes

• Positioning electrodes – Use consistent technique

– Limb electrodes ~ place at same level

– Precordial electrodes ~ specific intercostal spaces



49-22

Applying the Electrodes and the Connecting Wires (cont.)

• Attaching wires– Numbers and letters correspond to electrodes

– Connect limb wires first

– Precordial in same sequence as electrodes

– Avoid tension on wires



49-23

Operating the Electrocardiograph

• Standardize

• Run the ECG– Automatic– Manual– Multiple-channel

• Check the tracing– Clear– Free from artifact

Source: Courtesy of Cardiac Science Corporation, Milton, Wisconsin



49-24

Troubleshooting: Artifacts and Other Problems

• Artifacts – Improper technique

– Poor conduction

– Outside interference

– Improper handling

• Wandering baseline

Source: Courtesy of Cardiac Science Corporation, Milton, Wisconsin.



49-25

Troubleshooting: Artifacts and Other Problems (cont.)

• Flat line – loose or disconnected wire

• Extraneous marks – careless handling




49-26



• Causes – AC interference – Somatic interference




49-27


• Identifying source – Check tracings for leads I, II, and III

– If unable to identify source, stop and notify supervisor of problem

– Leave patient connected



49-28

Completing the Procedure

• Acceptable tracing– Label tracing properly

– Disconnect wires from electrodes

– Remove electrodes/wipe off electrolyte

– Assist patient as needed

– Prepare room appropriately

• Mount tracing if necessary



49-29

Completing the Procedure (cont.)

• Interpreting the ECG

– Not a medical assistant responsibility

– Be able recognize a problem requiring immediate attention



49-30


• Interpreting the ECG – heart rhythm– Regularity of the heartbeat

– Distances between complexes and waves is normally consistent

– Rhythm strip – lead II

To example



49-31


• Heart rate – count QRS complexes in a 6-second strip and multiply by 10

• Intervals and Segments – look for variations in length and position

• Wave changes – should be similar appearance in each lead

To example



49-33


• Cardiac Arrhythmias

– Ventricular fibrillation

– Premature ventricular contractions

– Atrial fibrillation



49-34


1. Electrodes are placed at how many positions on the body?

ANSWER: Ten: four limb and six chest positions.

2. What should you do just prior to running the ECG to see if the machine needs adjusting? What should you do upon completion of the test?

ANSWER: Standardize the electrocardiograph prior to running the tracing. Upon completion of the ECG, you should check the tracing to be sure is it clear and free from artifact.



49-35


3. What should you do just prior to running the ECG to see if the machine needs adjusting? What should you do upon completion of the test?

ANSWER: Standardize the electrocardiograph prior to running the tracing. Upon completion of the ECG, you should check the tracing to be sure is it clear and free from artifact.

4. What are four general causes of artifacts?

ANSWER: They are improper technique, poor conduction, outside interference, and improper handling of the tracing.



49-36

Exercise Electrocardiography (Stress Testing) and Echocardiography

• Exercise electrocardiography or stress test – measures response to exercise

• Echocardiography – Ultrasound – Resting or post exercise



49-37

Exercise Electrocardiography

• Uses

• Procedure – monitoring during exercise

• Medical assistant– Prepare and monitor patient– Be sure consent form is signed– Patient instructions



49-38

Echocardiography

• Purpose

• Types

– Transthoracic

– Transesophageal

– Doppler

– Stress echo

• Medical assistant– Be sure consent form

is signed– Patient instructions



49-39

Ambulatory Electrocardiography (Holter Monitoring)

• Monitors heart over a 24-hour period of normal activity

• Function – 24 hour recording– Tracing irregularities

compared to events in diary

• Patient education– Keep diary– What to avoid– How to check monitor



49-40


What is the purpose for stress testing, echocardiogram, and Holter monitor testing?

ANSWER: Stress testing is used to measure the heart’s response to a constant or increasing workload.

An echocardiogram shows the working heart valves and chambers and how well the blood moves through the heart.

A Holter monitor is used to obtain a tracing over a period of time when a resting ECG or stress test shows no abnormalities.

All are used for diagnosing cardiac conditions or for monitoring current treatments and medications.

Correct!



49-41

Pulmonary Function Testing

• Evaluates lung volume and capacity

• Uses– Evaluate of shortness of breath – Detect and classify of pulmonary disorders– Evaluate effectiveness of treatments



49-42

Spirometry

• Measures breathing capacity

• Spirometer – Mouthpiece – Mechanism to measure volume– Means of calculating and printing results

• Forced vital capacity



49-43

Performing Spirometry

• Patient preparation– Inform the patient about conditions and

activities that could affect the test accuracy

– Explain procedure and its purpose

– Position the patient properly

– Explain and demonstrate correct procedure



49-44

Performing Spirometry (cont.)

• Performing the maneuver– Forcefully coach and provide feedback

– Obtain three acceptable maneuvers

– Observe the patient’s symptoms

– Notify physician if symptoms occur



49-45


• Medication effectiveness

– Perform test before patient takes medication

– Repeat after patient takes the medication



49-46


• Medication effectiveness

– Perform test before patient takes medication

– Repeat after patient takes the medication

• Special considerations

– Uncooperative patients

– Patients who do not understand

– Patients who cannot follow directions

– Patients who cannot perform the procedure



49-47


• Calibration – Daily ~ keep

logbook– Calibration

syringe

• Infection control– Clean after patient

testing– Dispose of items

appropriately

• Results of testing



49-48

Peak Expiratory Flow Rate (PEFR)

• Peak flow meter – Reveal narrowing of airways prior to an

asthma attack

– Physician determines peak flow zones



49-49

Peak Expiratory Flow Rate (PEFR)



49-50

Pulse Oximetry

• Measurement of the oxygen saturation – Measures amount of light absorbed by

hemoglobin– Hypoxemia ~ less than 95%

• Uses – Pulmonary and cardiac

conditions– Postoperatively– Sleep apnea



49-51


1. What is the purpose of PFTs?

ANSWER: To evaluate lung volume and capacity.

2. What does successful spirometry testing depend on?

ANSWER: On proper patient preparation and consistent technique in preforming the procedure and analyzing the results.



49-52


3. Joey Jackson called to ask about taking his asthma medicine. He said he has been using his peak flow meter and the readings have been in his yellow zone. What do you tell him?

ANSWER: This means that his large airways are beginning to narrow and that he should take his medication as prescribed.

4. Joey decided to come to the office and you check his oxygen saturation with the pulse oximeter. The reading was 93%. What does this mean and what should you do?

ANSWER: Joey is hypoxemic. You need to notify the physician and document findings.

Very good!



49-53

In Summary

49.1 As a medical assistant, you will be responsible for preparing the patient for ECG and pulmonary function tests, maintaining the equipment used for these tests, and performing them.



49-54

In Summary (cont.)

49.2 The heart’s conduction system is responsible for the electrical pathway that occurs during a heartbeat.

The pathway begins with the SA node, travels through the AV node, Bundle of HIS, Right and Left bundle branches, and ends with the Purkinje fibers.

This electrical energy pathway is measured with an electrocardiograph and a tracing of the impulses is produced. The electrical impulses are represented in wave forms or deflections. Each deflection is

labeled by letters PQRSTU and represents a part of the pattern.



49-55

In Summary (cont.)

49.3 The electrocardiograph consists of the following components: electrodes, amplifier, stylus, leads, and ECG paper.

49.4 The steps in obtaining an accurate ECG include preparing the room and equipment, identifying the patient, properly placing the limb and chest

electrodes, attaching the lead wires, entering the patient data into the ECG machine, running the tracing, checking the tracing for artifacts, disconnecting the patient from the lead wires and removing the electrodes, and assisting the patient as required.



49-56

In Summary (cont.)

49.5 Exercise electrocardiography is referred to as stress testing. This measures the efficiency of the heart during constant or increasing workload.

Echocardiography uses ultrasound to create a picture of the moving heart. This can be done while the patient is resting or after exercise.

49.6 A Holter monitor is used to measure the heart’s activity over a 24-hour period. This is used when the patient has intermittent chest pain or discomfort and a normal ECG and stress test.



49-57

In Summary (cont.)

49.7 Forced vital capacity is the measurement of the greatest volume of air expelled when a patient

performs a rapid, forced expiration.

Accurate spirometry testing includes proper patient positioning, coaching the patient during the

procedure, obtaining three acceptable maneuvers, and recording the results in the patient’s chart.

A peak expiratory flow rate is obtained by having the patient sit or stand using good posture, take in as deep a breath as possible, and blow out through the peak flow meter as fast and as hard as possible three times.



49-58

In Summary (cont.)

49.8 Pulse oximetry testing is performed by applying the pulse oximeter to the patient’s finger or toe, attaching the sensor cable to the oximeter, turning the oximeter on, setting the alarm limits for high and low oxygen saturations, and reading the patient’s oxygen

saturation levels. The oxygen saturation levels should be recorded in the patient’s chart.



49-59

End of Chapter 49

As the arteries

grow hard, the heart

grows soft.~ H. L. Mencken



49-6052-60


1. What should you after running an ECG?

ANSWER: After making sure the tracing is acceptable, you should label it properly, disconnect wires from electrodes, remove electrodes and wipe off electrolyte, assist patient up, and prepare the room appropriately for the next patient.

CHAPTER © 2014 by McGraw-Hill Education. This is proprietary material solely for authorized instructor use. Not authorized for sale or distribution in.

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