Site Map

Electrocardiogram

ECG; EKG

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

Images

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

I Would Like to Learn About:

How the Test is Performed

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

The patches are connected by wires to a machine that turns the heart's electrical signals into wavy lines, which are often printed on paper. The doctor reviews the test results.

You will need to remain still during the procedure. The health care provider may also ask you to hold your breath for a few seconds as the test is being done.

It is important to be relaxed and warm during an ECG recording because any movement, including shivering, can alter the results.

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

How to Prepare for the Test

Make sure your health care provider knows about all the medicines you are taking. Some drugs can interfere with test results.

Do not exercise or drink cold water immediately before an ECG because these actions may cause false results.

How the Test will Feel

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

An ECG is used to measure:

An ECG is often the first test done to determine whether a person has heart disease. Your doctor may order this test if:

There is no reason for healthy people to have yearly ECG tests.

Normal Results

Normal test results include:

What Abnormal Results Mean

Abnormal ECG results may be a sign of:

Some heart problems that can lead to changes on an ECG test include:

Risks

There are no risks.

Considerations

The accuracy of the ECG depends on the condition being tested. A heart problem may not always show up on the ECG. Some heart conditions never produce any specific ECG changes.

Related Information

Exercise stress test
Holter monitor (24h)
Chest pain
Heart palpitations
Dilated cardiomyopathy
Arrhythmias
Pulse - bounding
Ectopic heartbeat
Stable angina
Pericarditis
Myocarditis
Electrolytes
Heart attack
Anorexia nervosa
Aortic dissection
Aortic insufficiency
Aortic stenosis
Atrial fibrillation or flutter
Atrial septal defect (ASD)
Cardiac tamponade
Coarctation of the aorta
Delirium tremens
Coronary artery spasm
Digitalis toxicity
Drug-induced lupus erythematosus
Hypokalemic periodic paralysis
Guillain-Barré syndrome
Heart failure - overview
High potassium level
Hypertensive heart disease
Hypertrophic cardiomyopathy
Hypoparathyroidism
Mitral valve regurgitation
Mitral stenosis
Mitral valve prolapse
Multifocal atrial tachycardia
Narcolepsy
Obstructive sleep apnea - adults
Paroxysmal supraventricular tachycardia (PSVT)
Patent ductus arteriosus
Pericarditis - constrictive
Pericarditis - after heart attack
Peripartum cardiomyopathy
Primary amyloidosis
Hyperaldosteronism - primary and secondary
Pulmonary hypertension
Pulmonary embolus
Pulmonary valve stenosis
Restrictive cardiomyopathy
Sick sinus syndrome
Stroke
Systemic lupus erythematosus
Tetralogy of Fallot
Thyrotoxic periodic paralysis
Transient ischemic attack
Transposition of the great vessels
Tricuspid regurgitation
Type 2 Diabetes
Unstable angina
Ventricular septal defect
Ventricular tachycardia
Wolff-Parkinson-White syndrome

References

Ganz L. Electrocardiography. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 54.

BACK TO TOP

Review Date: 5/13/2014  

Reviewed By: Michael A. Chen, MD, PhD, Associate Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, Washington. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional 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. © 1997- 2016 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

adam.com