Holter Monitor and Event Monitor

What is the test?

A Holter monitor is a portable EKG device that records your heart rhythm over time, outside the hospital or doctor's office. Whereas a regular EKG examines your heart's electrical activity for a few seconds, the Holter monitor examines changes over a sustained period of time-usually a 24- to 48-hour period-while you go about your daily activities and even while you sleep. One type of Holter monitor, called an "event monitor," can be used to record rhythms over a longer time, such as a 30-day period. Doctors use Holter monitor or event monitor tests to evaluate symptoms that come and go and that might be related to heart-rhythm changes or coronary artery disease.

How do I prepare for the test?

Men with a lot of hair on their chest will probably have to shave it. Otherwise, there's no special preparation.

What happens when the test is performed?

A technician in your doctor's office or a diagnostic lab fits you with a Holter monitor and explains how to use it. Five stickers are attached to your chest. Wires snap onto each of these stickers and connect them to the monitor. The wires detect your heart's electrical pattern throughout the day, while the monitor records and stores the data for doctors to interpret later. You can fit the monitor into a purse or jacket pocket or wear it over your shoulder by its strap.

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