Holter monitoring is continuous monitoring and recording of the ECG (Echocardiogram) for 24 hours, 48 hours, 14 days or 28 days. It is useful for evaluating intermittent arrhythmias and, secondarily, for detecting hypertension. The Holter monitor is portable, enabling patients to participate in normal daily activities. Patients are asked to record symptoms and activities so that they may be correlated with events on the monitor. The Holter monitor does not automatically analyze the ECG data; a physician does so at a later date.