What is an event monitor?

An event monitor, or recorder, is a wearable device that records the electrical activity of your heart periodically for up to a month. While a Holter monitor (another device used at home to diagnose cardiovascular disease) gathers data about the heart’s activity continuously, an event monitor records data only when an “event” is occurring—that is, when you are experiencing symptoms. It requires that the patient track when they are having symptoms, usually by pushing a button on the monitor. The monitor also has the ability to automatically record events that are out of the normal range.

The monitor is a small electronic device that is connected with wires to sticky patches (electrodes) that are placed on the skin of your chest. The monitor is small enough to clip to your belt or keep in your pocket.

Cardiac event monitoring is very similar to Holter monitoring, and is often ordered for the same reasons. (The Holter monitor is a type of electrocardiogram (ECG or EKG) used to monitor the ECG tracing continuously for a period of 24 hours or longer. A standard or "resting" ECG is one of the simplest and fastest procedures used to evaluate the heart.) With an event monitor, you wear ECG electrode patches on your chest, and the electrodes are connected by wire leads to a recording device.

Unlike the Holter monitor, however, which records continuously throughout the testing period of 24 to 48 hours, the event monitor does not record until you feel symptoms and trigger the monitor to record your ECG tracing at that time. An auto-trigger event monitor may be used to record rhythms when symptoms are rare or suspected to occur during sleep. The auto-trigger event monitor automatically records rhythm events and can be manually activated if you experience symptoms.

An event recorder is a portable device that records the electrical activity in your heart when an abnormal cardiac “event” occurs.

For example, if you feel dizzy or develop shortness of breath or chest pain, or feel your heart pounding or beating very fast, the event recorder captures an electrocardiographic (ECG) tracing at that moment. You then send the tracing to your doctor over a telephone line for analysis.

Some event recorders are similar to Holter monitors. They use sticky electrode patches that are worn on the chest continuously, sense the heart’s electrical activity and transmit that data over connecting wires to the event recorder. Other event recorders can be carried in your pocket and simply held over your heart or clipped on a finger or a wrist when you feel symptoms.

The most important difference between an event recorder and a Holter monitor is that the event recorder does not continuously record and store information on your heart rhythm. Some event recorders automatically detect an abnormal heart rhythm and begin recording, but most are activated manually with the push of a button.

Another important difference is that Holter monitors are typically used for only 24 to 48 hours, while an event monitor may be used for a month or more.

An event monitor is a recording of your heart that gives your doctor information between appointments.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.