What you can expect

During

Holter monitoring is painless and noninvasive. You can hide the electrodes and wires under your clothes, and you can wear the recording device on your belt or attached to a strap. Once your monitoring begins, don't take the Holter monitor off — you must wear it at all times, even while you sleep.

While you wear a Holter monitor, you can carry out your usual daily activities. You'll usually be given a form to help you record your activities and any symptoms. It's particularly important to note if and when you have any of the following symptoms:

• Any pounding, fluttering or skipped heartbeats
• Shortness of breath
• Chest pain
• Lightheadedness

Write down what activities you do and exactly what time you do them.

Your doctor will tell you how long you'll need to wear the monitor. It may vary from 24 to 48 hours, depending on what condition your doctor thinks you have or how frequently you have symptoms of a heart problem. A wireless Holter monitor can work for weeks.

After

Once your monitoring period is over, you'll return the device to your doctor's office. If you were asked to keep a record of symptoms that you had while wearing the device, your doctor can compare data from the Holter monitor recorder with your notes. This can help your doctor diagnose your condition.