The Holter is a portable, battery-powered device that measures and records your heart activity (ECG)

The Holter is a portable, battery-operated device that continuously measures and records your heart activity (ECG) for 24 to 48 hours to record any events throughout the day such as a rapid heartbeat, a feeling of beat palpitations, an ear pulse, a very slow beating, an increase in beat, a fall or a blackout of unknown cause