Your experience while using a Holter or event monitor depends on the type of monitor you have. However, most monitors have some factors in common.
All monitors record the heart's electrical activity. Thus, maintaining a clear signal between the sensors (electrodes) and the recording device is important.
In most cases, the sensors are attached to your chest using sticky patches. Wires connect the sensors to the monitor. You usually can clip the monitor to your belt or carry it in your pocket. (Postevent recorders and implantable loop recorders don't have chest sensors.)
A good stick between the patches and your skin helps provide a clear signal. Poor contact leads to a poor recording that's hard for your doctor to read.
Oil, too much sweat, and hair can keep the patches from sticking to your skin. You may need to shave the area where your doctor will attach the patches. If you have to replace the patches, you'll need to clean the area with a special prep pad that your doctor will provide.
You may need to use a small amount of special paste or gel to help the patches stick to your skin. Some patches come with paste or gel on them.
Too much movement can pull the patches away from your skin or create "noise" on the EKG (electrocardiogram) strip. An EKG strip is a graph showing the pattern of the heartbeat. Noise looks like a lot of jagged lines; it makes it hard for your doctor to see the real rhythm of your heart.
When you have a symptom, stop what you're doing. This will ensure that the recording shows your heart's activity rather than your movement.
Your doctor will tell you whether you need to adjust your activity level during the testing period. If you exercise, choose a cool location to avoid sweating too much. This will help the patches stay sticky.
Other everyday items also can disrupt the signal between the sensors and the monitor. These items include magnets; metal detectors; microwave ovens; and electric blankets, toothbrushes, and razors. Avoid using these items. Also avoid areas with high voltage.
Cell phones and MP3 players (such as iPods) may interfere with the signal between the sensors and the monitor if they're too close to the monitor. When using any electronic device, try to keep it at least 6 inches away from the monitor.
While using a Holter or event monitor, your doctor will advise you to keep a diary of your symptoms and activities. Write down what type of symptoms you're having, when they occur, and what you were doing at the time.
The most common symptoms of heart rhythm problems include:
Make sure to note the time that symptoms occur, because your doctor will match the data with the information in your diary. This allows your doctor to see whether certain activities trigger changes in your heart rate and rhythm.
Also, include details in your diary about when you take any medicine or if you feel stress at certain times during the testing period.
Holter monitors are about the size of a large deck of cards. You'll wear one for 24 to 48 hours. You can't get your monitor wet, so you won't be able to bathe or shower. You can take a sponge bath if needed.
When the testing period is done, you'll return the device to your doctor's office. The results will be stored on the device.
The recording period for a standard Holter monitor might be too short to capture a heart rhythm problem. If this is the case, your doctor may recommend a wireless Holter monitor.
Wireless Holter monitors can record for a longer time than standard Holter monitors. You can use a wireless Holter monitor for days or even weeks, until signs or symptoms of a heart rhythm problem occur.
Wireless monitors record for a preset amount of time. Then they automatically send data to your doctor's office or a company that checks the data.
These monitors use wireless cellular technology to send data. However, they still have wires that connect the device to the sensors stuck to your chest.
The batteries in the wireless monitor must be changed every 1–2 days. You'll need to detach the sensors to shower or bathe and then reattach them.
Event monitors are slightly smaller than Holter monitors. They can be worn for weeks or until symptoms occur. Most event monitors are worn like Holter monitors—clipped to a belt or carried in a pocket.
When you have symptoms, you simply push a button on your monitor to start recording. Some event monitors start automatically if they detect abnormal heart rhythms.
Postevent recorders can be worn like a wristwatch or carried in a pocket. The pocket version is about the size of a thick credit card. These recorders don't have wires that connect the device to chest sensors.
To start the recorder when you feel a symptom, you hold it to your chest. To start the wristwatch version, you touch a button on the side of the watch.
You send the stored data to your doctor's office using a telephone. Your doctor will explain how to use the monitor before you leave his or her office.
Autodetect recorders are about the size of the palm of your hand. Wires connect the device to sensors on your chest.
You don't need to start an autodetect recorder. This type of monitor automatically starts recording if it detects abnormal heart rhythms. It then sends the data to your doctor's office.
Implantable loop recorders are about the size of a pack of gum. This type of event monitor is inserted under the skin on your chest. Your doctor will discuss the procedure with you. No chest sensors are used with implantable loop recorders.
Your doctor can program the device to record when you start it during symptoms or automatically if it detects an abnormal heart rhythm. Devices may differ, so your doctor will tell you how to use your recorder. Sometimes a special card is held close to the device to start it.
Clinical trials are research studies that explore whether a medical strategy, treatment, or device is safe and effective for humans. To find clinical trials that are currently underway for Holter and Event Monitors, visit www.clinicaltrials.gov.
December 9, 2013
Gary H. Gibbons
Epidemiologist Immerses Himself in Big Data as He Studies the Link Between HIV and Cardiovascular Disease
The NHLBI updates Health Topics articles on a biennial cycle based on a thorough review of research findings and new literature. The articles also are updated as needed if important new research is published. The date on each Health Topics article reflects when the content was originally posted or last revised.