Electrocardiogram (EKG or ECG)
What is an electrocardiogram?
An electrocardiogram (ECG or EKG) is one of the simplest and fastest procedures used to evaluate the heart. Electrodes (small, ambulance plastic patches) are placed at certain locations on the chest, arms, and legs. When the electrodes are connected to an ECG machine by lead wires, the electrical activity of the heart is measured, interpreted, and printed out for the doctor’s information and further interpretation.
Reasons for the procedure
Some reasons for your doctor to request an ECG include, but are not limited to, the following:
• To determine the cause of chest pain
• To evaluate other signs and symptoms which may be heart-related, such as fatigue, shortness of breath, dizziness, or fainting
• To identify irregular heartbeats
• To determine the status of the heart prior to procedures such as surgery and/or after treatment for conditions such as a heart attack (myocardial infarction, or MI), endocarditis (inflammation or infection of one or more of the heart valves), or after procedures such as heart surgery or cardiac catheterization
• To assess the function of an implanted pacemaker
• To determine the effectiveness of certain heart medications
• To obtain a baseline tracing of the heart’s function during a physical examination that may be used as a comparison with future ECGs, to determine if any changes have occurred
There may be other reasons for your doctor to recommend an ECG.
Risks of the procedure
An ECG is a quick, noninvasive method of assessing the heart’s function. Risks associated with ECG are minimal and rare.
Certain factors or conditions may interfere with or affect the results of the test. These include, but are not limited to, the following:
• Obesity, pregnancy, or ascites (accumulation of fluid in the abdomen)
• Anatomical considerations, such as the size of the chest and the location of the heart within the chest
• Movement during the procedure
• Exercise or smoking prior to the procedure
• Certain medications
• Electrolyte abnormalities, such as too much or too little potassium, magnesium, and/or calcium in the blood
Before the procedure:
• Your doctor or the technician will explain the procedure to you and offer you the opportunity to ask any questions that you might have about the procedure.
• Generally, fasting is not required before the test.
• Notify your doctor of all medications (prescribed and over-the-counter) and herbal supplements that you are taking.
• Notify your doctor if you have a pacemaker.
• Based on your medical condition, your doctor may request other specific preparation.
After the procedure
You should be able to resume your normal diet and activities, unless your doctor instructs you differently.
Generally, there is no special care following an ECG.
Notify your doctor if you develop any signs or symptoms you had prior to the test (for example, chest pain, shortness of breath, dizziness, or fainting).
Your doctor may give you additional or alternate instructions after the procedure, depending on your particular situation.
The content provided here is for informational purposes only, and was not designed to diagnose or treat a health problem or disease, or replace the professional medical advice you receive from your doctor. Please consult your health care provider with any questions or concerns you may have regarding your condition.
This page contains links to other websites with information about this procedure and related health conditions. We hope you find these sites helpful, but please remember we do not control or endorse the information presented on these websites, nor do these sites endorse the information contained here.
WebMD Heart Disease Health Center
American College of Cardiology
American Heart Association
A stress test can be used to test for heart disease. Stress tests are tests performed by a doctor and/or trained technician to determine the amount of stress that your heart can manage before developing either an abnormal rhythm or evidence of ischemia (not enough blood flow to the heart muscle). The most commonly performed stress test is the exercise stress test.
What Is an Exercise Stress Test?
The exercise stress test — also called a stress test, exercise electrocardiogram, treadmill test, graded exercise test, or stress ECG — is used to provide information about how the heart responds beach dresses to exertion. It usually involves walking on a treadmill or pedaling a stationary bike at increasing levels of difficulty, while your electrocardiogram, heart rate, and blood pressure are monitored.
Why Do I Need a Stress Test?
Your doctor uses the stress test to:
• Determine if there is adequate blood flow to your heart during increasing levels of activity
• Evaluate the effectiveness of your heart medications to control angina and ischemia
• Determine the likelihood of having coronary heart disease and the need for further evaluation
• Check the effectiveness of procedures done to improve blood flow within the heart vessels in people with coronary heart disease
• Identify abnormal heart rhythms
• Help you develop a safe exercise program
What Are the Types of Stress Tests?
There are many different types of stress tests, including:
Treadmill stress test : As long as you can walk and have a normal ECG, this is normally the first stress test performed. You walk on a treadmill while being monitored to see how far you walk and if you develop chest pain or changes in your ECG that suggest that your heart is not getting enough blood.
Before your stress test:
- Do not eat or drink anything except water for four hours before the test.
- Do not drink or eat foods containing caffeine for 12 hours before the test. Caffeine will interfere with the results of your test.
- Do not take the following heart medications on the day of your test unless your doctor tells you otherwise, or if the medication is needed to treat chest discomfort the day of the test: Isosorbide dinitrate (for example, Isordil, Dilatrate SR); Isosorbide mononitrate (for example, ISMO, Imdur, Monoket); Nitroglycerin (for example, Deponit, Nitrostat, Nitro-bid). Your doctor may also ask you to stop taking other heart drugs on the day of your test. If you have any questions about your medications, ask your doctor. Do not discontinue any drug without first talking with your doctor.
- If you use an inhaler for your breathing, bring it to the test.