Holter and event monitors are heart monitors that record the heart's electrical activity. Cardiologists most often use these heart monitors to diagnose arrhythmias. These are problems with the speed or rhythm of the heartbeat. During an arrhythmia, the heart can beat too fast, too slow, or irregularly.
Holter and event monitors also are used to detect silent myocardial ischemia. In this condition, not enough oxygen-rich blood reaches the heart muscle. "Silent" means that no symptoms occur.
Cardiologists can also monitor whether treatments for arrhythmia and silent myocardial ischemia are working.
Holter and event monitors are similar to an EKG (electrocardiogram). An EKG is a simple test that detects and records the heart's electrical activity. It's the most common test for diagnosing a heart rhythm problem.
However, a standard EKG only records the heartbeat for a few seconds. It won't detect heart rhythm problems that don't occur during the test.
Holter and event monitors are small, portable devices. You can wear one while you do your normal daily activities. This allows the monitor to record your heart for a longer time than an EKG.
Cardiologists know some people have heart rhythm problems that only occur during certain activities, such as sleep or physical exertion. Using a Holter or event monitor increases the chance of recording these problems.
Although similar, Holter and event monitors aren't the same. A Holter monitor is a heart monitor that records your heart's electrical activity the entire time you're wearing it. An event monitor only records your heart's electrical activity at certain times while you're wearing it.
Types of Holter and Event Monitors
Holter monitors are sometimes called continuous EKGs (electrocardiograms). This is because Holter monitors record the heart rhythm continuously for 24 to 48 hours.
A Holter monitor is about the size of a large deck of cards. You can clip it to a belt or carry it in a pocket. Wires connect the device to sensors (called electrodes) that are stuck to your chest using sticky patches. These sensors pick up your heart's electrical signals, and the monitor records your heart's rhythm.
Wireless Holter Monitors
Wireless Holter monitors have a longer recording time than standard Holter monitors. The wireless version records your heart's electrical activity for a preset amount of time.
These monitors are called wireless because they use a cell phone to send the data to your doctor's office. This happens automatically at certain times. These monitors still have wires that connect the device to the sensors stuck to your chest.
You can use a wireless Holter monitor for days or even weeks until signs or symptoms of a heart rhythm problem occur. These monitors usually are used to detect heart rhythm problems that don't occur often.
Although wireless Holter monitors work for longer periods, they have a down side. You must remember to write down the time of symptoms, so your doctor can match it to the heart rhythm recording. Also, the batteries in the wireless monitor must be changed every 1 to 2 days.
Event monitors are similar to Holter monitors. You wear one while you do your normal daily activities. Most event monitors have wires that connect the device to sensors that are stuck to your chest using sticky patches.
Unlike Holter monitors though, event monitors don't continuously record the heart's electrical activity. They only record when symptoms occur. For many event monitors, you need to start the monitor when you feel symptoms.
Event monitors tend to be smaller than Holter monitors because they don't need to store as much data.
Different types of event monitors work in slightly different ways. Your doctor will explain how to use the monitor before you start wearing it.