What is Event Monitoring?

Event monitoring is a recording of your heart rhythm when you are having symptoms, or an "event."

You carry a small, lightweight recorder over aperiod of days or weeks. When you feel symptoms, such as dizziness, palpitations, fainting spells, or chest pain, you press a button to record your heart's electrical activity. The test helps your doctor determine whether your symptoms are caused by a heart problem.

What Does Event Monitoring Show?

An abnormal heart rhythm, called an arrhythmia, is a change in either the speed or pattern of the heartbeat. During an arrhythmia, the heart may beat too fast, too slowly, or irregularly.

Doctors can diagnose an arrhythmia by doing an electrocardiogram, or ECG, which is a recording of the heart’s electrical activity. During a standard ECG test, the heart's electrical signals are recorded on a strip of paper.

Quite often, an arrhythmia will not occur during the brief recording at the doctor's office. If your doctor suspects you have an arrhythmia, he or she will want to record the ECG over a longer period of time.

If your symptoms are frequent (several times a week), your doctor may do a 24-hour recording of your ECG, called Holter monitoring. The recorder, which is worn on a strap over your shoulder or around your waist, records the ECG continuously, whether or not you have symptoms.

However, if your symptoms occur less often, you may need monitoring for longer than 24 hours. In that case, your doctor may order an event recorder, which is worn over a period of days or weeks.

Why Is Event Monitoring Done?

There are several reasons why event monitoring may be done:

• To determine whether symptoms such as dizziness, palpitations, fainting spells, or chest pain are caused by heart disease,
• To detect arrhythmias that occur irregularly or infrequently.
• To see how well arrhythmia treatments (such as medications or pacemakers) are working to detect poor blood flow to the heart muscle, which can be a sign of coronary heart disease.

How Does It Work?

There are two basic types of event recorders; one has a memory loop and one does not.

• Memory-Loop Recorder
  A recorder with a memory loop can record the heart's electrical activity not only during symptoms and afterwards, but also for a minute or so before an event. This is useful for patients whose symptoms happen so quickly that they do not have time to turn on the recorder immediately.

The memory-loop (or pre-event) recorder is about the size of a pager. It can be clipped to your belt or placed in a shirt pocket. Two or three sticky patches, called electrodes, are applied to your chest and connected by wires to the recorder.

The recorder continuously scans your heart's electrical activity. When you feel symptoms, you activate the recorder by pressing a button. The device records and stores a minute or two of ECG data before, during, and after the event.

The recorder can store several minutes of ECGs from one or more separate events. At a later time, you transmit the data over the telephone to a receiving station.

• 
  
  Post-Event Recorder
  A post-event recorder does not have a memory loop, so it can only begin recording rhe hearts electrical activity after it is activated.

This type of recorder is usually smaller and lighter than a memory-loop recorder. It may be the size and shape of a credit card or may look like a wristwatch. The recorder doesn't have electrodes that are attached to your chest (instead, it has small metal discs that function as the electrodes).

You carry the credit-card style recorder in a pocket or purse. When you feel symptoms, you hold the back of the card against the skin of your chest and press a button to activate the recorder. The device records and stores about a minute of heart rhythm during and after the event.

The wristwatch style recorder is worn on your wrist. As soon as you feel symptoms, you press a button and rest the palm of your hand on top of the face of the watch. The device records and stores about a minute of heart rhythm.

How Is the Test Done?

You'll pick up the recorder at the doctor's office, test center, or hospital. A nurse or a technician will show you how to operate the device. You may also be given printed instructions to take with you.

If you are given a memory-loop recorder (see page 4), you will be shown how to apply the electrodes. It is important to rotate the electrodes every day to avoid skin irritation. If you do notice skin irritation from the electrodes, call your doctor. Do not swim, take a bath, or shower while wearing the recorder.

You'll use the event recorder for several days or weeks, You can go about your normal daily activities while carrying the recorder. When you feel symptoms, you press the "RECORD" button to activate the device.
The recorder can store several separate events. You'll be told whether to transmit (send) your ECG after each event or wear until the recorder's memory is full.

To transmit your ECG data over the telephone, you call the receiving center. When you are instructed to do so, you press the "SEND" button on the recorder and place the telephone mouthpiece over the device. The stored ECG data are transmitted to the receiving center, where they are printed and reviewed by a team of nurses and/or ECG technicians.


Keeping a Diary

You'll also be asked to keep a diary during the period you use the recorder. This diary lets your doctor compare your activities and symptoms with the data on the ECG recordings.

The information you will need to write in the diary includes the following:

• What you were doing (walking, climbing stairs, sleeping, etc.) when an event occurred.
• The symptoms you experienced (such as dizziness, palpitations, fainting spells, chest pain, etc.).
• The date and time at which the event occurred

Event Monitor Diary
Date	Time	Activity	Symptoms
July 20	8 20 am 12:35 pm	Walking 2 miles Having lunch	Racing heart, dizziness a few skipped beats fluttering in the chest chest pressure
July 22	9:50 am 10:15 pm	Meeting with client Climbing stairs

Your Test Results

Once the data are transmitted to the receiving center, they are reviewed and analyzed. The information is then sent to your doctor. This allows the doctor to make an accurate diagnosis and develop a treatment plan that is best for you.