Ambulatory Electrocardiogram

How It Is Done

Your doctor will choose the type of heart monitor that is most likely to help diagnose your heart problem. You may have a monitor that records your heart activity all of the time or only some of the time.

• A continuous monitor records your heart activity all of the time. Examples are a Holter monitor and a wireless patch monitor.
• An event monitor records your heart activity only when you have symptoms or a change in your heart rhythm. It may monitor you all of the time and record only when it detects a problem. Or it may only work when you start the monitor at the times you have symptoms.

Continuous monitors

Continuous recorders are a common type of monitor used for this test.

A Holter monitor gives a 24- to 48-hour record of the electrical signals from your heart. Wireless patch monitors can be used for many days. A standard EKG monitors only 40 to 50 heartbeats during the brief time you are attached to the machine. A continuous recorder monitors about 100,000 heartbeats in 24 hours. It is likely to find any heart problems that happen with activity.

You will see a doctor or technician to get your heart monitor and to learn how to use it.

• Several areas on your chest may be shaved and cleaned.
• The pads or patch will be attached to the skin of your chest. For pads, thin wires will connect the electrodes to the monitor.
• You may be hooked up briefly to a standard EKG machine. This is done to check that the electrodes are working as they should.

Event monitors

Event monitors are used when symptoms of an abnormal heart rhythm do not happen very often. This kind of recorder can be used for a longer time than a continuous recorder. The information collected by an event monitor can often be sent over the phone or online to a doctor's office, clinic, or hospital.

You may be told to call your doctor, clinic, or hospital while you are having symptoms or soon after you record your heart rhythm. This way the information on the monitor can be looked at right away.

There are different types of monitors.

• Loop recorders. A loop recorder constantly monitors your heartbeats. It records your heartbeats only when you have symptoms or an abnormal heart rhythm. The device might start recording when you press a button, or it might automatically record when an abnormal heart rhythm happens. Loop recorders are called this because they save a small amount of information about how your heart was beating right before the monitor started recording. This feature is especially useful for people who pass out when their heart problems occur and can press the button only after they wake up.
  • Electrode pads or a patch may be attached to your chest in the same way as with a continuous recorder. When you have symptoms, you press a button on the monitor to record your heart rhythm. If you pass out, you should start the recorder as soon as you wake up. Also, be sure a friend or family member knows how to start the recorder if you pass out.
  • One type of loop recorder can be placed under the skin of your chest. This is done with surgery. You might have this monitor for a year or more. This may be a good choice for people who have symptoms that happen rarely, such as once every 6 months. The recorder may start recording on its own when it detects an abnormal heartbeat. Or you might use a handheld device to start the monitor when symptoms occur.
• Handheld event monitors. This small device records your heartbeats only when you have symptoms. You are not attached to the machine. There are different types of event monitors.
  • One type is worn on the wrist like a watch. When you have symptoms, you press a button to start the EKG recording.
  • The other type is a device that you carry where you can reach it easily, such as in your purse or pocket. When you have symptoms, you press the back of the device against your chest. Then you press a button to start the recording. The back of the device has small metal discs that work like electrodes. These handheld monitors can be very small. (Some are about the size and shape of a credit card.) The event monitor records heart signals only when you hold it against your chest.

Using your heart monitor

Your doctor will explain the details of how to use your monitor. If you have to do anything to send your heart data, your doctor will show you how.

What you do during the test

Your doctor may ask you to keep a diary of all of your activities and symptoms while you wear the monitor. You will write down the type of activity you were doing and the time your symptoms started. For example, write down the exact times when you:

• Exercise or climb stairs.
• Eat.
• Urinate or have a bowel movement.
• Have sex.
• Sleep.
• Get upset.
• Take medicine.

If you have any symptoms of heart problems, such as dizziness, fainting, chest pain, or abnormal heartbeats, push the event-marker button on the recorder to mark it (if you have the type that allows you to). Then write down the exact time and how long the symptom lasts. For example, you might write: "12:30 p.m. Ate lunch. 1:00 p.m. Argument with boss, had chest tightness for several minutes."

If you have electrodes that are connected to a monitor, try to sleep with the recorder placed carefully at your side. This will help keep the electrodes from getting pulled off. If one of the electrodes or lead wires comes loose, a light on the monitor will flash. Press on the center of each electrode to see if you can restore the contact. Call your doctor if one of the electrodes comes off and you can't get it to stay on.

Your doctor will tell you if you need to stay away from strong electromagnetic fields while wearing a monitor. These may include magnets, remote controls for garage door openers, microwave ovens, and electric blankets. Do not use an electric toothbrush or shaver. And try to stay away from metal detectors and high-voltage areas. Signals from these types of electronic equipment can sometimes affect the recording.

What you and your doctor do after the test

At the end of the recording period, your doctor will give you instructions. If you had electrode pads or a patch, you may go to the doctor's office or hospital to have them removed. Or you may be able to remove them yourself. Your doctor will let you know how to return the monitor.

Your doctor will review the data from your monitor and also look at your records of activities and symptoms and times they occurred. Your doctor will compare the timing of your activities and symptoms with the recorded heart pattern.