1. Electrocardiography Lesson 3: ECG-Related Diagnostic Procedures49
Electrocardiography
Lesson 3:
ECG-Related Diagnostic Procedures

2. Lesson Objectives
Upon completion of this lesson, students should be able to …
Define and spell the terms to learn for this chapter.
Understand stress testing.
Comprehend the need for Holter monitoring and how to attach leads.

3. Lesson Objectives
Explain telemetry and identify the sites for lead attachment.
Comprehend the function and placement of pacemakers.

4. Special ECG Tests
There are some special ECG tests that may be performed in the physician’s office:
Rhythm strip: An ECG run on lead II for 20 seconds when something abnormal appears (or if physician requests it)
Inspiration strip: An ECG strip run on lead II for 10 seconds with the patient holding his or her breath 4

5. Exercise Tolerance Testing
Also called a stress test or treadmill test
Evaluation of the heart’s response during moderate exercise following a 12-lead ECG 5

6. Exercise Tolerance Testing
May be used for:
Evaluating patients with a high risk for developing heart disease or known to have heart disease
Evaluating patients about to begin a strenuous exercise program
Evaluating patients who have cardiac complaints
Evaluating patients after rehabilitation following cardiac surgery 6

7. Exercise Tolerance Testing
Patient should be given instructions before test day to wear comfortable exercise or walking shoes and loose-fitting clothes
ECG is recorded as patient walks at a specified pace and incline in the presence of a physician
Blood pressure is checked frequently 7

8. Exercise Tolerance Testing
Physician evaluates the effect of exercise on the heart rate, blood pressure, and ECG
Test may be stopped if patient experiences trouble breathing or complains of chest pain
Emergency equipment should be ready to use 8

9. Exercise Tolerance Testing9

10. Placement of Sensors for the Stress Test
Sensors are all placed on the torso
Precordial sensors (V1–V6) are placed as for the regular ECG
Arm and leg sensors are put at the midclavicular line on the top of the torso and on the midclavicular line on the abdomen
Electrodes should adhere securely to the skin and may need to be taped in place
A male patient with a very hairy chest may need to be shaved to improve attachment of electrodes

11. Guidelines for the Stress Test
The stress test is continued until 85% of the maximum target heart rate is achieved or the patient becomes symptomatic
The maximum target heart rate is calculated by using the following formula: 220 minus the patient’s age = the maximum target heart rate for that person
For a sixty year old patient = 160 x .85 = 136 or the maximum target heart rate for this patient

12. Guidelines for the Stress Test
For patients who have had myocardial infarction (MI) or heart attack, the target heart rate is set lower at 70%.
This is known as a submaximal test

13. Use of Thallium
A radioisotope used in nuclear medicine that emits gamma rays
Sometimes injected into the patient’s vein during a stress test for better understanding of perfusion (blood flow to the myocardium)
Injected during the last minute of exercise
Patient lies on a special table and a gamma camera takes pictures

14. Use of Thallium
If the heart muscle is ischemic (receiving less than normal amount of blood flow) poor uptake of the thallium will occur
Normal perfusion of the myocardium is indicated by “hot spots” on the pictures

15. Pharmacologic Stress Testing
Involves no exercise
A medication is given to the patient that causes the heart rate to climb to the target heart rate
Continuous ECGs and vital sign evaluation are performed
Test is useful on patients with physical limitations or the elderly who cannot perform enough exercise to elevate the heart rate

16. Patient Safety During a Stress Test
Maintain emergency equipment that might be needed
Have the emergency equipment in the room at the time of the test
Oxygen equipment, a defibrillator, an airway, intravenous solutions, and medications should be periodically checked and replaced, if outdated or not functioning
Always be sure a physician is available when a stress test is done

17. Holter Monitor
Records cardiac activity while the patient is ambulatory
Test is run for at least a 24-hour period
Performed when the ECG is not conclusive or the cardiac irregularity was not captured on the tracing 17

18. Holter Monitor
A small tape recorder and a patient diary are used to detect heart irregularities that are infrequent and not detected with a standard ECG
Can record continuously or when patient presses an “event” button when symptoms occur
The medical assistant may instruct the patient and apply the chest sensors 18

19. Holter Monitor 19

20. Holter Monitor Diary
The associated diary is important in Holter monitoring procedures
Patients should carry out all routine daily activities except for showering and bathing
Patients should avoid areas of high voltage
Patients should use the diary to record their activities during the day and when they have pressed the “event” button
The physician will compare the tape to the diary log of activity to help in the evaluation of the heart 20

21. Holter Monitor Electrodes
There are five special disposable chest sensors that are securely attached to the body 21

22. Placement of Holter Monitor Electrodes
Third intercostal space - 2 or 3 inches to the right of the sternum
Third intercostal space - 2 or 3 inches to the left of the sternum
Fifth intercostal space - at the left sternum margin
Sixth intercostal space - at the right anterior axillary line
Sixth intercostal space - at the left anterior axillary line 22

23. Telemetry
Involves using radio waves to transmit the heart’s electrical activity to a central monitoring station
Allows the patient to move around the room or other limited space while the heart is monitored
Patient should be made aware of the range of movement permitted
Used in inpatient facilities but may be encountered in ambulatory care settings as well 23

24. Pacemakers
Involves using radio waves to transmit the heart’s electrical activity to a central monitoring station
Allows the patient to move around the room or other limited space while the heart is monitored
Patient should be made aware of the range of movement permitted
Used in inpatient facilities but may be encountered in ambulatory care settings as well 24

25. Pacemakers 25

26. Placement of a Pacemaker
A permanent epicardial pacemaker. The pulse generator can be placed in subcutaneous pockets in the subclavian or abdominal regions.

27. Questions? 27