During the procedure
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. 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 suspects you have or how frequently you have symptoms of a heart problem. A wireless Holter monitor can work for weeks.
You'll be asked to keep a diary of all your daily activities while you're wearing the monitor. Write down what activities you do and exactly what time you do them. Also write down any symptoms you have while you're wearing the monitor, such as chest pain, shortness of breath or skipped heartbeats.
Your doctor can compare data from the Holter monitor recorder with your diary, which can help diagnose your condition.
After the procedure
Once your monitoring period is over, you'll return the device to your doctor's office, along with the diary you kept while you wore the Holter monitor. Your doctor will compare the data from the recorder and the activities and symptoms you wrote down.