A Holter monitor is a device that records the electrical activity of the heart for a 24-72 hour period. The Holter monitor records every heartbeat, giving the patient's physician access to an inclusive report of all cardiac activity occuring during the study. It does this by utilizing 5-12 leads attached to the patient's skin with electrodes. These electrodes assist in the creation of a clear recording by the Holter monitor.

When a Holter monitoring study is complete the data is sent to a lab where a report is created and returned to the patient's physician. The patient's physician then uses the information provided by the Holter monitor to diagnose and recommend further treatment for the patient.