Electrocardiography Lesson 3: ECG-Related Diagnostic Procedures 49 Electrocardiography Lesson 3: ECG-Related Diagnostic Procedures

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.

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

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

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

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

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

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

Exercise Tolerance Testing 9

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

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 220 - 60 = 160 x .85 = 136 or the maximum target heart rate for this patient

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

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

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

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

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

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

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

Holter Monitor 19

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

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

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

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

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

Pacemakers 25

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

Questions? 27