EKG - Electrocardiogram

An electrocardiogram, also called an EKG or ECG, is a simple test that detects and records the electrical activity of the heart. It is used to detect and locate the source of heart problems.

Electrical signals in the heart trigger heartbeats. These signals start at the top of the heart in an area called the right atrium. (Read about "The Heart & Its Valves") The electrical signals travel from the top of the heart to the bottom. They cause the heart muscle to contract as they travel through the heart. As the heart contracts, it pumps blood out to the rest of the body. (Read about "The Heart & Cardiovascular System")

An EKG shows how fast the heart is beating. It shows the heart's rhythm, whether it is steady or irregular. It also records the strength and timing of the electrical signals as they pass through each part of the heart.

EKG recordings of this electrical activity can help reveal a number of heart problems, including but not limited to:

• heart attack - EKG recordings can help doctors diagnose a heart attack that is happening now or has happened in the past. This is especially true if doctors can compare a current EKG recording to an older one. (Read about "Heart Attack")
• a heart that is beating irregularly, or too fast or too slow (Read about "Arrhythmia")
• disease in the heart valves between the different heart chambers (Read about "The Heart & Its Valves")
• birth defects in the heart (Read about "Congenital Heart Defects")
• heart conditions such as congestive heart failure (Read about "Congestive Heart Failure")

An EKG can also identify an area of the heart that is receiving less blood flow than is should, which can be an indication of a higher risk of a heart attack.

During an EKG, a technician first attaches soft patches called electrodes to the skin of the chest, arms and legs. These electrodes are about the size of a quarter. To help an electrode stick to the skin, the technician may have to shave a patch of hair where the electrode will be attached.

After the electrodes are placed on the skin, you lie still on a table for a few minutes while the electrodes detect the electrical signals of the heart. A machine then records these signals on graph paper or displays them on a screen.

The entire test takes about 10 minutes. After the test, the electrodes are removed from the skin and discarded.

Holter Monitor

A Holter monitor is a type of EKG that continuously records your heart's rhythms. The monitor is worn for a period of time, such as 24 hours, while you go about your normal activities.

At the start of the testing time period, electrodes attached to the monitor are connected to your chest. The monitor records your heart's electrical activity during the period of time. Meanwhile, you should be keeping a log of the things you're doing while wearing the monitor. After the period of time is up, you go back to your doctor, who will look at the records and see if there have been any irregular heart rhythms.

A Holter monitor can be used to monitor a patient after a heart attack (Read about "Heart Attack"), to monitor the effectiveness of heart medications or to check for irregularities in heart rhythm (Read about "Arrhythmia").

Event Monitors

Event monitors can be similar to Holter monitors, but they are used by patients over a longer period of weeks or months. Electrodes attached to the monitor can be connected to your chest. The monitor is always on but it will record your heart rhythm only when it is activated. The monitor stores the rhythm for review by your doctor. An event monitor can be used to check for irregularities in heart rhythm while you're having symptoms (Read about "Arrhythmia").

Related Information:

    Cardiovascular Tests