The Holter monitor is a portable device used to make a continuous recording of your heart rate and rhythm as you go about your daily routine. A cardiologist uses the information from the device to detect heart rhythm abnormalities, determine whether your medications need adjusting, or to match your symptoms with heart activity.

If you have signs and symptoms of an arrhythmia, such as palpitations (episodes of rapid heartbeats) or unexplained fainting or dizziness, your doctor may recommend wearing a Holter monitor for 72 hours to 14 days. Over that period, the Holter monitor will record abnormalities in your heart rate and rhythm. Additionally, you can press the Event button to document when you feel a specific symptom. This helps a cardiologist assess whether your symptoms are related to abnormal electrical activity in your heart.