Twenty-four hour Holter monitoring is a continous test to record your heart's rate and rhythm for 24 hours. You wear the Holter monitor for 12 to 48hours as you go about your normal daily routine. This device has electrodes and electrical leads exactly like a regular EKG, but it has fewer leads. it can pick up not only your hearts rate and rhythm but also when you feel chest pains or exhibit symptoms of an irregular heartbeat, or arrhythmia.