A Holter monitor is a battery-operated portable device that measures and records your heart’s activity (ECG) continuously for 24 to 48 hours or longer depending on the type of monitoring used. The device is the size of a small camera. It has wires with silver dollar-sized electrodes that attach to your skin. The Holter monitor and other devices that record your ECG as you go about your daily activities are called ambulatory electrocardiograms.
Regular electrocardiograms (ECGs or EKGs) let your doctor look at your heart’s activity at one point in time during your ECG test. But abnormal heart rhythms and cardiac symptoms may come and go. That’s why your doctor may want to evaluate your heartbeat over time while you go about your normal activities. You may be asked to wear a Holter monitor if you have fast, slow or irregular heartbeats called arrhythmias.
Wearing the monitor may tell your doctor:
- If your medicines are working
- Why you have symptoms such as dizziness, faintness or the feeling that your heart is racing or skipping a beat
- If your heart is getting enough oxygen to meet its needs