Event monitors are similar to Holter monitors in that they monitor heart activity. Unlike Holter monitors, however, event monitors only record during symptoms. When experiencing symptoms, the event monitor must be started manually to record heart activity. Because event monitors need to record less data than Holter monitors, they are smaller in size, some being wearable wrist watches.
Holter monitoring is a test procedure that uses a holter monitor to record heart rate during regular activity over a 24-48 hour time period. The test uses electrodes placed on the chest connected to a small battery operated monitor that records the information. The monitor can be carried in a pocket or small pouch attached to the neck or waist.
Normal activity should be observed during this test, while exercise may be requested by the doctor if symptoms have previously occurred. Make sure to record all activity and symptoms experienced, including the time they occurred, so the doctor may match the monitor data.