A Holter monitor, also called an ambulatory ECG, records the electrical signals of your heart for a full 24- or 48-hour period.
The purpose of a Holter monitor is to record heart signals during typical daily activities and while sleeping, and to find heart problems that may occur for only a few minutes out of the day.
You wear small patches called electrodes on your chest that are connected by wires to a small, portable recorder. The recorder can be clipped to a belt, kept in a pocket, or hung around your neck.During the 24 or 48 hours, you do your usual daily activities and keep a notebook, noting any symptoms you have and the time they occur.
You then return both the recorder and the notebook to your doctor to read the results. Your doctor, by reviewing the recording, can see how your heart was beating at the time you had symptoms.