How It Is Done

Continuous recorders

Continuous recorders are the most common type of ambulatory electrocardiogram monitor. This type includes the Holter monitor.

A continuous recorder provides a 24- to 72-hour record of the electrical signals from your heart. A standard EKG monitors only 40 to 50 heartbeats during the brief period you are attached to the machine. A continuous recorder monitors about 100,000 heartbeats in 24 hours and is likely to find any heart problems that happen with activity.

For this test, you wear a lightweight, battery-operated tape recorder (monitor) on a strap over your shoulder or around your waist. The recorder is connected by wires to small metal discs (electrodes) taped to your chest. The electrodes detect the electrical signals from your heart. A clock is connected to the recorder so you can note what time it is when you have any symptoms.

You will be fitted with the recorder and electrodes by a technician in a doctor's office or hospital room.

• Several areas on your chest may be shaved and cleaned, and then a small amount of electrode paste or gel will be applied to those areas.
• The electrode pads will then be attached to the skin of your chest, with thin wires connecting the electrodes to the monitor.
• You may be hooked up briefly to a standard EKG machine to ensure that the electrodes are working properly.

What you do during the test

While wearing the continuous recorder, you will also be asked to keep a diary of all your activities and symptoms, including the type of activity you were doing and the time your symptoms started. In the diary, write down the exact times when you exercise, climb stairs, eat, urinate, have a bowel movement, have sex, sleep, get emotionally upset, take medicine, or perform other activities. If you have any symptoms of heart problems, such as dizziness, fainting, chest pain, or palpitations, push the event-marker button on the recorder to mark it and 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."

When you sleep, try to stay on your back with the recorder carefully positioned at your side so that the electrodes are not 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.

While you are wearing a monitor, try to stay away from magnets, metal detectors, high-voltage areas, garage door openers, microwave ovens, and electric blankets. Do not use an electric toothbrush or shaver. Signals from these types of electronic equipment can sometimes interfere with the recording.

What you and your doctor do after the test

At the end of the recording period (usually 24 to 72 hours), you will return to the doctor's office or hospital to have the electrodes removed, or you may be able to remove the electrodes yourself. You will return the Holter monitor to your doctor's office or hospital. The recorded tape will be read by computer to provide information about your heart rate, the frequency of your heartbeats, and any irregularities.

Your doctor will 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.

Implantable continuous recorders

Another type of continuous recorder can be implanted under the skin of the chest. This recorder can be kept in your chest for more than a year to record the electrical signals from your heart.

Intermittent recorders

Another kind of ambulatory EKG monitoring is the intermittent recorder, which is used when symptoms of an abnormal heart rhythm do not occur very often. An intermittent recorder can be used for a longer time than a continuous recorder. The information collected by an intermittent recorder can often be sent over the phone to a doctor's office, clinic, or hospital.

You may be instructed to call your doctor, clinic, or hospital while you are having symptoms or soon after you record your heart rhythm so that the information on the monitor can be analyzed right away.

The procedure for intermittent recording depends on the type of monitor used.

• Loop recorder. A loop recorder constantly records your heartbeats. This recorder lets you indicate when you have symptoms. Loop recorders also save a small amount of information about how your heart was beating when you pressed the recording button (presymptom recording). This feature is especially useful for people who lose consciousness when their heart problems occur and can press the button only after they wake up.
  • Electrodes will be attached to your chest in the same way as 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.
  • An implantable form of the loop recorder can be worn for several weeks and may be a good choice for people who have symptoms that occur rarely, such as once every 6 months. It is surgically placed under the skin of the chest. The recorder might automatically start recording when it detects an arrhythmia. Or, you might use a handheld device to start the monitor when symptoms occur.
• Event monitor. This small device records your heartbeats only when symptoms of the heart problem occur. You are not attached to the machine. There are two types of event monitors.
  • One type is worn on the wrist like a watch. When symptoms occur, 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 symptoms occur, you press the back of the device against your chest and then 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 are holding it against your chest.