Holter monitor

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.
Quick facts:

You may be asked to wear a Holter monitor to see if you have a slow, fast or irregular (uneven) heartbeat. Or, your doctor may use it to see how well your medicines are working to treat these problems. If you have a pacemaker and feel dizzy, your doctor may use a Holter monitor to find out if your pacemaker is working properly.
This monitor has no risks and wearing it isn’t painful.
The results of wearing a Holter monitor will help you and your doctor decide if you need more tests or medicines for your heart, or if you need a pacemaker or cardioversion procedure to restore a regular heart rhythm.