Holter monitoring is a continuous ECG recording, usually for 24-48 hours, while you go about your normal daily activities. It is useful to detect arrhythmias that may not occur during a resting ECG. During Holter monitoring, wires are connected to your chest and attached to a small recording device that you carry with you. If you experience any symptoms, you are asked to push a button and record your symptoms so that your heart rhythm at the time of your symptoms can be determined. An arrhythmia specialist will later analyze the electrical recordings to determine what your actual heart rhythm was at the time that you were experiencing your symptoms and also whether any asymptomatic abnormal heart rhythms occurred while you were wearing the Holter monitor.