A holter heart monitor is a small device that can be worn at home. It is really just an ECG that is taken over an extended period of time to track the heart’s rhythm and heartbeats. Holter monitoring is typically performed after an ECG if your doctor feels that he needs more information about the condition of your heart’s rhythm. A holter ECG is likely to be able to pick up any irregularities in your heartbeat. When wearing a holter monitor it is important to go about your daily activities normally, although one will not be able to take a bath or shower. It is also useful to keep a diary of activities and symptoms experienced while wearing the device.