Holter monitors are portable, battery-operated electrocardiogram (EKG/ECG) recorder devices that are used to diagnose heart arrhythmias. The Holter monitor provides physicians with continuous cardiac data in a 24-hour time period.

A Holter monitor is used to determine how your heart responds to normal activity. Your physician may prescribe a monitor for you:

After a heart attack
To diagnose heart rhythm problems
When starting a new heart medicine

You wear a Holter monitor during your normal daily activities to record your cardiac rhythms. Electrodes are attached to your chest and connected to the monitor by lead wires, continuously recording electrocardiographic signals for up to 24 hours. Your physician will probably ask you to record a daily activity diary during your Holter monitor test, including:

Time of day
Activity – from taking medicine to eating dinner, each daily activity needs to be recorded
Symptoms – pain, dizziness, etc., all need to be documented, even if the symptom seems unimportant

At the end of the test, the recorder’s memory is analyzed on a computer. Your physician compares the Holter monitor’s data to your activity journal to match up what activities correspond to the recorded heart events.

What to expect during Holter monitor testing

Preparing for your procedure

Make sure to take a shower prior to getting fitted for your Holter monitor, since you can’t get the monitor wet during the course of the test. Minimize the use of skin moisturizers, so the electrode patches stay attached to your skin.

During your procedure

A nurse or technician will clean your skin and attach electrode patches. Wires connect the patches to the monitoring device. The monitor can be worn under your clothes and you should keep it on as long as your physician has instructed. In addition, it is important to record all daily activities in your diary.

After your procedure

Your physician will discuss the Holter monitor test results with you and compare the monitor’s data to your activity diary. Your physician will determine appropriate next steps after evaluating the test data.