Lipp Vis Nursing ChaptLWBK1630_C02_p013-068
18 Chapter 2 • Cardiovascular Care Release of Cardiac Enzymes and Proteins
Exercise Stress Testing A stress test, sometimes called a
treadmill test or exercise test, is done while the patient walks or runs on a motorized treadmill. The test is based on the principle that exercise increases myocardial demand and coronary artery blood supply which may be inadequate during exercise and stress which can result in myocardial ischemia. Exercise stress testing is a nonevasive procedure that assesses the heart’s response to an increased workload. The test can demonstrate if the blood supply is reduced in the arteries that supply the heart during exercise and identify appropriate exercise levels for the patient.
Onset of
chest pain 6 hrs
12 hrs
18 hrs
24 hrs
30 hrs
36 hrs
42 hrs
48 hrs
3 days
4 days
5 days
6 days
7 days
8 days
9 days
10 days
11 days
12 days
Enzyme
50
20
15
10
5
4
3 2 increase above normal Normal range
Supplemental right precordial leads
KEY:
Troponin I Troponin T
Myoglobin CK-MB
CARDIAC TESTS Electrocardiography The electrocardiogram (ECG) is a graphical
V 3R V 1R V 2R
V 5R
V 4R
Mid-clavicle
representation (time versus amplitude of electrical vector projection) of the electrical activity of the heart. While imperfect as a diagnostic or prognostic tool, it provides a significant amount of information and is a first-line test necessary for the proper care of the patient with potential cardiovascular disease. The standard 12-lead ECG is of great value in identifying myocardial ischemia, MI, rhythm and conduction disturbances, chamber enlargement, electrolyte imbalances, and drug toxicity.
Anterior axillary line
Horizontal plane of V 4
LA
RA
–V 6
V 3
V 5
V 1
V 2
V 4
ECG machine
ECG strip
RL
LL
Reprinted with permission from Hinkle JL, Cheever KH. Brunner & Suddarth’s Textbook of Medical-Surgical Nursing . 13th ed. Philadelphia: Wolters Kluwer; 2013.
EKG electrode placement with standard left and right precordial leads.
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