Holter monitoring is continuous recording of the electrical activity of the heart.
The test is usually done on a person who has had an abnormal heart rhythm, or arrhythmia, especially one that occurs only occasionally and therefore is usually missed by a routine ECG. It can also be used to observe the effects of heart medicines, or to monitor heart activity after a heart attack.
A Holter monitor is a portable electrocardiogram device. It continually records a person's heart activity. The monitor is worn during a day and night of normal activities. To perform the test, small electrodes from the monitor are attached to the chest. The person carries the device in a pocket or a pouch. The individual also keeps a diary of activities and symptoms during the monitoring period.
When the 24-hour heart recording and diary are complete, the healthcare professional will compare the events of the day to the heart's activities. The professional will try to match abnormalities on the heart recording with entries in the diary. Computers are also used to look for heartbeat irregularities in the recording.
A person having this test should receive instructions from a healthcare professional on how to properly prepare for the test.
Abnormal results show irregular heart rhythms. By comparing the diary entries with the heart record, the healthcare professional may be able to determine the cause of the arrhythmias. For example, if the rhythm disturbances are connected with stressful events, there may be an emotional basis for the arrhythmias that can be treated with stress management. Examining the diary along with the Holter monitor results can also suggest various physical reasons for the arrhythmias.