What is an Electrocardiogram (ECG)? | MedStar Health

A test to record electrical signals in the heart

Each time your heart beats, an electrical signal travels through the heart. An electrocardiogram, also known as an ECG or EKG, measures how fast this signal travels and how much electrical activity is happening in your heart. This can help us determine whether you have an irregular heartbeat, known as an arrhythmia, if your heart is overworked, or whether you’ve had a heart attack, as well as other heart conditions.

If your doctor suspects a heart condition that doesn’t appear on a standard ECG, you may need one of the other types of heart rhythm monitoring we offer, including:

What to expect from an electrocardiogram

For a standard ECG, you’ll lie down on a bed or table. A technician will place patches called electrodes on your chest and possibly on your arms and legs. The technician may need to clean or shave the areas to make sure the electrodes adhere to your skin.

The electrodes are connected to a machine that displays your heart’s electrical signals as wavy lines. You’ll need to lie still during the test, which should take just a few minutes. Afterward, you should be able to resume your normal activities. The test won’t be painful, and the only side effect you may notice is a slight rash where the electrodes stuck to your skin. This rash usually goes away on its own.

Your doctor will review the results of your ECG and discuss them with you. Additional testing or treatment options may depend on these results.



Angioplasty improves blood flow through the arteries by clearing plaque buildup.

Anomalous left coronary artery from the pulmonary artery surgical treatment

Several methods can be used to correct anomalous left coronary artery from the pulmonary artery (ALCAPA), in which the left coronary artery branches off from the pulmonary artery instead of the aorta.

Arrhythmia (heart rhythm) treatments

Treatments for arrhythmias, or heart rhythm disorders, such as minimally invasive procedures, implantable devices, and surgery vary based on the type and severity of your condition.

Atrial fibrillation ablation

Atrial fibrillation ablation uses extreme heat or cold to destroy tissue causing faulty electrical signals in the heart.

Balloon valvuloplasty

Balloon valvuloplasty improves blood flow through the heart to the lungs and body by opening a stiff heart valve.

Cardiac ablation

Cardiac ablation uses heat or cold to destroy heart tissue causing abnormal heart rhythms known as arrhythmias.

Cardiac implant closure device

Cardiac implant closure devices are used to repair defects that allow blood to flow through a hole connecting the chambers of the heart.

Cardiac rehabilitation

Cardiac rehabilitation is an exercise program designed to help people recover from certain heart conditions or treatments.

Catheter ablation for atrial fibrillation

Catheter ablation is a minimally invasive procedure that uses heat or cold to destroy heart tissue causing atrial fibrillation, a type of abnormal heart rhythm.

Congenital heart disease treatments

Treatments for congenital heart conditions range from atrial septal defect and patent foramen ovale closures to cardiac ablations, heart valve replacements, and heart transplants.

Convergent (maze) procedure

A convergent maze procedure is a procedure that aggressively treats atrial fibrillation (AFib). Maze procedures create a pattern, or maze, of scar tissue in the heart to disrupt faulty electrical signals causing your abnormal heart rhythm.

Coronary artery bypass surgery

Coronary artery bypass surgery, also known as coronary artery bypass graft (CABG) surgery, restores normal blood flow through narrowed or blocked coronary arteries by using a healthy blood vessel taken from your leg, arm, or chest to create a detour around the problem area.

Coronary artery stenting

Coronary artery stents are small mesh tubes placed within the artery to prevent blockages and allow better blood flow.

Electrical cardioversion

Electrical cardioversion uses electrical shocks to treat heart rhythm disorders.

Endovascular repair of thoracic aortic aneurysms

Endovascular repair of a thoracic aortic aneurysm is a catheter-based procedure to place a stent within the aorta to support weakened tissue.

Heart failure surgery

Surgical treatments for heart failure can include coronary bypass surgery, mechanical support devices and heart transplants.

Heart failure treatment

Treatments for heart failure such as medications, surgery and mechanical devices vary based on the cause and severity of your condition.

Heart surgery (maze) for atrial fibrillation

A surgical maze procedure treats atrial fibrillation (AFib) by creating a pattern, or maze, of scar tissue in the heart to disrupt faulty electrical signals causing your abnormal heart rhythm.

Heart transplants

A heart transplant replaces a diseased, failing heart with a healthier heart from a donor.

Implantable cardioverter defibrillator (ICD)

An implantable cardioverter defibrillator (ICD) is a device implanted below your collarbone that monitors your heart’s rhythm. When it detects an abnormal rhythm, it delivers an electrical impulse or shock to the heart to correct it.

Infective endocarditis surgery

Infective endocarditis surgery is the removal of infected heart tissue and repair or replacement of damaged heart valves.

Inotropic therapy

Inotropic therapy is an IV medication that can relieve symptoms of heart failure and abnormal heart rhythms.

Intestinal PAD treatment options

Intestinal PAD treatment options include medication, minimally invasive procedures, and surgery.

Intra-aortic balloon counterpulsation

Intra-aortic balloon counterpulsation uses a balloon pump at the end of a catheter to push blood through your arteries and assist your heart as it pumps blood.

Intracoronary radiation therapy

Intracoronary radiation therapy is an innovative treatment that uses radiation to prevent scar tissue buildup in the arteries after an angioplasty or stent placement.

Lead extraction

If the wire that delivers electrical shocks from a pacemaker or ICD is no longer working correctly, your doctor will need to remove it.

Leadless pacemakers

A leadless pacemaker is a small capsule placed in the heart’s right ventricle that delivers an electric pulse to regulate the heartbeat.

Left atrial appendage closure

Closing the left atrial appendage can decrease the risk of dangerous blood clots and stroke for patients with atrial fibrillation.

Left ventricular assist device (LVAD)

A left ventricular assist device (LVAD) helps the heart pump blood more effectively during end-stage heart failure.

Left ventricular reconstructive surgery (modified DOR procedure)

During left ventricular reconstructive surgery, the left ventricle is reshaped to remove scar tissue caused by heart failure.

Minimally invasive heart surgery

Minimally invasive heart surgery is used whenever possible to reduce risks and shorten recovery time after surgery to treat a variety of conditions.


MitraClip is a device our doctors use to treat mitral insufficiency, also known as mitral regurgitation.

Mitral valve disease treatments

Mitral valve disease treatments may include medication, minimally invasive procedures and surgery to treat a damaged valve.

Mitral valvuloplasty

Mitral valvuloplasty improves blood flow through the heart to the lungs and body by opening a narrow or stiff heart valve.

Off-pump bypass surgery (beating-heart bypass)

Off-pump bypass surgery, also known as beating-heart bypass surgery, is an option for many patients to have coronary artery bypass surgery without needing to stop the heart or lungs during the procedure.


A pacemaker is a device that helps control various types of heart rhythm disorders.

Percutaneous valve treatments

Percutaneous valve procedures use catheter-based methods to replace a damaged heart valve and are less invasive than traditional open-heart surgeries.

Pulmonary valve repair and replacement

Pulmonary valve repair and replacement procedures include minimally invasive and traditional surgery as well as several types of replacement material.

Pulmonary vein isolation

Pulmonary vein isolation creates scar tissue to disrupt electrical signals coming from the pulmonary veins that cause atrial fibrillation (AFib), a type of abnormal heart rhythm.

Radiofrequency ablation for atrial fibrillation

Radiofrequency ablation uses extreme heat to destroy heart tissue causing an abnormal heart rhythm known as atrial fibrillation.

Alcohol septal ablation

Alcohol septal ablation, also known as septal alcohol ablation, is a minimally invasive procedure our doctors use to treat hypertrophic cardiomyopathy. The procedure shrinks abnormal tissue and improves blood flow throughout the body.

Septal myectomy

Septal myectomy is a surgical procedure to remove overgrown heart muscle and improve blood flow through the heart. Stenting [Link: /services/stenting/] Stenting uses a mesh tube to open narrow blood vessels and improve blood flow.


Stenting uses a mesh tube to open narrow blood vessels and improve blood flow.

Transcatheter aortic valve replacement (TAVR)

Transcatheter aortic valve replacement (TAVR) is a minimally invasive option to replace a narrowed aortic valve that fails to open properly and blocks the flow of blood.

Structural heart and valve disease treatments

Structural heart and valve disease treatments address defects or abnormalities with the heart’s muscle or valves with or without surgery.

Transcatheter pulmonary valve replacement (TPVR)

Transcatheter pulmonary valve replacement (TPVR) is a minimally invasive option to replace a damaged pulmonary valve that reduces blood flow from the heart to the lungs.

Transcatheter tricuspid valve replacement

Transcatheter tricuspid valve replacement is a non-surgical procedure to replace a damaged tricuspid valve.

Transradial catheterization

Transradial catheterization is a form of cardiac catheterization in which doctors use the radial artery, located in the wrist, to treat many heart and vascular conditions.

Tricuspid valve surgery

Tricuspid valve surgery includes repair or replacement of a damaged valve using traditional or minimally invasive methods.

Valve disease treatments

Valve disease treatments include monitoring, medication, or surgery to repair or replace a damaged valve.

Valve sparing or valve preserving surgery (reimplantation surgery)

Valve sparing surgery is a procedure to repair an aortic root aneurysm without replacing the aortic valve.

Ventricular assist device (VAD)

A ventricular assist device (VAD), also known as a mechanical circulatory support device, helps the heart pump blood more effectively during end-stage heart failure.

WATCHMAN™ device (left atrial appendage closure)

We can implant a WATCHMAN device to permanently seal off the left atrial appendage (LAA), which is a small pouch in the top left chamber of the heart that is the site of almost all stroke-causing blood clots in people with atrial fibrillation (AFib).

Wearable cardioverter defibrillator

A vest that contains a device that monitors your heart and, if an abnormal heart rhythm is detected, delivers a shock to restore a normal heartbeat.

Our providers

Dr Brian Case listens to the heart of a patient during an office visit at MedStar Health. Both people are wearing masks.

Expert cardiology care

Getting the care you need starts with seeing one of our cardiologists

Ask MedStar Heart & Vascular Institute

Have general questions for our heart and vascular program? Email us at AskMHVI@medstar.net. If you have clinically-specific questions, please contact your physician’s office.