Medical Encyclopedia

 

Medical Encyclopedia

Other encyclopedia topics:  A-Ag  Ah-Ap  Aq-Az  B-Bk  Bl-Bz  C-Cg  Ch-Co  Cp-Cz  D-Di  Dj-Dz  E-Ep  Eq-Ez  F  G  H-Hf  Hg-Hz  I-In  Io-Iz  J  K  L-Ln  Lo-Lz  M-Mf  Mg-Mz  N  O  P-Pl  Pm-Pz  Q  R  S-Sh  Si-Sp  Sq-Sz  T-Tn  To-Tz  U  V  W  X  Y  Z  0-9 

Electrocardiogram

Contents of this page:

Illustrations

ECG
ECG
Atrioventricular block, ECG tracing
Atrioventricular block, ECG tracing
High blood pressure tests
High blood pressure tests
Electrocardiogram (ECG)
Electrocardiogram (ECG)

Alternative Names    Return to top

ECG; EKG

Definition    Return to top

An electrocardiogram (ECG) is a test that records the electrical activity of the heart.

See also:

How the Test is Performed    Return to top

You will be asked to lie down. The health care provider will clean several areas on your arms, legs, and chest, and then attach small patches called electrodes to the areas. It may be necessary to shave or clip some hair so the electrodes stick to the skin.

The number of patches used may vary.

You usually need to remain still, and you may be asked to hold your breath for short periods during the procedure. It is important to be relaxed and relatively warm during ECG recording. Any movement, including muscle tremors such as shivering, can alter the results.

The electrodes are connected by wires to a machine that converts the electrical signals from the heart into wavy lines, which are printed on paper and reviewed by the doctor.

Sometimes this test is done while you are exercising or under minimal stress to monitor changes in the heart. This type of ECG is often called a stress test.

How to Prepare for the Test    Return to top

Make sure your health care provider knows about all the medications you are taking, as some can interfere with test results.

Exercising or drinking cold water immediately before an ECG may cause false results.

How the Test Will Feel    Return to top

An ECG is painless. No electricity is sent through the body. The electrodes may feel cold when first applied. In rare cases, some people may develop a rash or irritation where the patches were placed.

Why the Test is Performed    Return to top

An ECG is used to measure:

An ECG is a very useful tool for determining whether a person has heart disease. Your doctor may order this test if you have chest pain or palpitations.

An ECG may be included as part of a routine examination in patients over age 40.

Normal Results    Return to top

What Abnormal Results Mean    Return to top

Abnormal ECG results may be a sign of

Additional conditions under which the test may be performed include the following:

Risks    Return to top

There are generally no risks. An ECG only monitors the heart's electrical activity. No electricity is sent through the body, so there is no risk of shock.

Considerations    Return to top

The accuracy of the ECG depends on the condition being tested. Some heart conditions are not detectable all the time, and others may never produce any specific ECG changes.

A person who has had a heart attack or who may have heart disease may need more than one ECG. There is no reason for healthy people to undergo annual testing unless they have a family history of heart disease or another medical condition.

Update Date: 9/3/2008

Updated by: Larry A. Weinrauch MD, Assistant Professor of Medicine, Harvard Medical School, Cardiovascular Disease and Clinical Outcomes Research, Watertown, MA.. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

A.D.A.M. Logo

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 1997-2009, A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.