Certain abnormal heart rhythms may occur only intermittently or only under certain conditions, such as stress. They can be difficult to view on a traditional ECG machine in your physician’s office. If this is the case, your physician will request a Holter monitor.

A Holter monitor, also called a continuous electrocardiogram, continuous ECG or ambulatory ECG, is a small, portable electrocardiogram device that monitors your heart’s electrical activity for 24 hours or longer. This allows your physician to track, capture and analyze any abnormal rhythms that occur during the normal routines of your everyday life.

The monitor consists of electrodes (small, plastic patches) placed at certain locations on your chest and abdomen. The electrodes are connected to recording device by lead wires, allowing the electrical activity of your heart to be measured, interpreted and printed out for your physician’s information and further interpretation.

You will receive instructions regarding how long you will need to wear the recorder, how to keep a diary of your activities and symptoms during the test, and personal care and activity instructions, which include keeping the device dry while you are wearing it.