Using an Event Monitor

Event monitoring is a painless way to record your heart's electrical activity. It helps to diagnose abnormal heart rhythms and other health conditions. It records your heart’s activity when you have symptoms. The monitor is a small, battery-operated, portable electrocardiogram (ECG) machine. You can get your monitor at a hospital, at a test center, at a doctor's office, or in the mail.

Event monitors come in a few forms. Some are a small patch that sticks right to your chest. Others use small sticky pads (electrodes) on your chest that are connected by thin wires to a small recorder that you carry or clip on your belt. The device records the same kind of information as an electrocardiogram (ECG). But it records the information for longer periods of time, usually at least 1 minute at a time.

Event monitors work in a few different ways. They all record your heart's rhythm, but they differ in how the information is recorded and provided to your care team.

• Symptom event monitor. You press a button when you feel a symptom, and the monitor saves your heart rhythm at that moment.
• Memory looping monitor. This monitor records all the time. You press a button when you feel a symptom, and the monitor saves your heart rhythm at that moment and also saves the information from a few minutes before the device was activated. This is so that data from before, during, and after the symptom will be captured.
• Auto-detecting monitors. Many newer monitors can find and save an abnormal rhythm on their own, even when you feel nothing, in addition to recording when you press the button.

Some monitors send the information to your care team on their own. Others store it, so the monitor has to be returned or the data uploaded before your team can review it.

A doctor may think that you have an abnormal heart rhythm based on your health history, even if your ECG looks normal. Some abnormal heart rhythms happen less often and for only a short time. In this case, an ECG is not likely to pick up the abnormal heart rhythm. An event monitor may be a better choice for you. That way, you can record your heart's electrical activity when you are having symptoms. The event monitor can also help show what type of abnormal rhythm you have. It's best for rhythm abnormalities that happen now and then or that are caused by certain symptoms.

You may need to wear an event monitor if:

• Your heartbeat is too fast, too slow, or irregular.
• You have symptoms such as palpitations, dizziness, or fainting, or you feel your heart is beating too hard or skipping a beat.
• Your doctor wants to check how well the treatment for an abnormal heart rhythm is working. You may have to wear a monitor after a coronary ablation or cardioversion to see that your heart is still in a normal rhythm with these types of treatments.
• You have had an open heart surgery, such as a heart valve replacement or repair or bypass grafting. The heart muscle can become irritated and more likely to have abnormal heart rhythms as you recover at home.

Event monitors are generally very safe. They don't cause any pain. In some cases, the sticky patches that are used to attach the sensors to your chest can cause skin irritation and blistering. Many event monitor companies have alternative electrodes that are better for sensitive skin. Contact your doctor if you have skin irritation.

Your doctor will show you how to use your event monitor.

Before you put your sensors on your chest, your skin should be clean of oils, creams, and sweat. Clean your skin before putting the sensors on. You may need to shave the area before applying. A technician will show you how to place the sensors. Or the monitor may be mailed to your home with instructions for using it. Follow all instructions about exercise. Sweat can make the sensors come off. If you have a cardiac memory looping monitor, change your sensors as instructed.

You may need to wear your event monitor for several days or up to a month. You will also need to keep a diary while using your event monitor. Record any symptoms when they happen, and note what you were doing at the time.

• When you have a symptom, push the button to start recording. (Some start recording automatically when an abnormal rhythm is detected.)
• Stop moving. This will help the device get a good recording. The device should record for several minutes.
• After the event, write down the time, your symptoms, and what you were doing when the event happened.

Some monitors send your recordings to your care team on their own, so you don't have to do anything. A trained person checks them. Some monitors ask you to send the recordings yourself using an app or a small device. Your care team will show you how. In some cases, you may need to go see your doctor.

Some electronic devices can disrupt the monitor. If you can, don't use these during the time you're wearing the monitor. But when you need to use an electronic device, keep it at least 6 inches away from the monitor. This includes things such as:

• Cell phones.
• Electric blankets.
• Electric razors.
• Electric toothbrushes.
• Magnets.
• Metal detectors.
• Microwave ovens.

Note: Don't use large motors or construction equipment near the monitor. They can cause interference. The monitor can mistake the vibrations for abnormal heart rhythms.

After a few readings, you may be able to stop wearing your event monitor. Your doctor may use those readings to start your treatment. In some cases, you may need more testing. Follow-up tests might include:

• Exercise stress test. This shows how your heart responds to exercise and how well it handles increased oxygen demands.
• Tilt table test. This may be done if you have had fainting.
• Electrophysiology testing. This invasive procedure can give more details about your heart's electrical signal.
• Echocardiogram. This is done to evaluate the structure and pumping function of your heart and its valves.