The Holter monitor test is the original, and still most widely used type of ambulatory electrocardiographic (ECG) monitoring. The main aim of a Holter monitor study is to analyze the electrical activity of the heart outside of the clinical setting—that is, as a person goes about their normal daily activities.
When a person has a Holter monitor test, they wear the monitoring device for either 72 hours or can be for a week, and the ECG recorded during this time is subsequently analyzed for any cardiac arrhythmias that might have occurred during the monitoring period, as well as for any signs of cardiac ischemia.
The Holter monitor study is very effective in diagnosing cardiac arrhythmias, as long as they occur with sufficient frequency. The test is very safe.
The Holter monitor is named for Norman J. Holter, the physicist chiefly responsible for its invention in the 1950s.
A Holter monitor detects infrequent or fleeting cardiac arrhythmias.
There are many types of cardiac arrhythmias. They can produce various symptoms, and they differ tremendously in their medical significance and in their treatments.
However, many cardiac arrhythmias occur only infrequently and completely unpredictably—and are often present for only brief periods of time. The odds of capturing one of these rare or fleeting arrhythmias while a healthcare provider happens to be recording a standard ECG (which records the heart rhythm for only 12 seconds) is quite small.
Furthermore, symptoms caused by arrhythmias may also last for only a short period of time. By the time a person experiencing symptoms can get to a medical facility to have an ECG recorded, all too often the symptoms (and the arrhythmia that caused them) have gone away.
This is where the Holter monitor’s value comes in. By recording each and every heartbeat that occurs over a prolonged period of time, while a person goes about their activities of daily life, the odds of detecting one of these transient arrhythmias are greatly increased.