An electrocardiogram (ECG) records the electrical signals in the heart. It's a common and painless test used to quickly detect heart problems and monitor the heart's health.

During an ECG, up to 12 sensors (electrodes) are attached to the chest and limbs. The electrodes are sticky patches with wires that connect to a monitor. They record the electrical signals that make the heart beat. A computer records the information and displays it as waves on a monitor or on paper.

An electrocardiogram is a painless, noninvasive way to help diagnose many common heart problems. A health care provider might use an electrocardiogram to determine or detect:

• Irregular heart rhythms (arrhythmias)

• If blocked or narrowed arteries in the heart (coronary artery disease) are causing chest pain or a heart attack

• Whether you have had a previous heart attack

• How well certain heart disease treatments, such as a pacemaker, are working

You may need an ECG if you have any of the following signs and symptoms:

• Chest pain

• Dizziness, lightheadedness or confusion

• Heart palpitations

• Rapid pulse

• Shortness of breath

• Weakness, fatigue or a decline in ability to exercise

ECG results can give a health care provider details about the following:

• Heart rate

• Heart rhythm

• Heart attack

• Blood and oxygen supply to the heart

• Heart structure changes