Recording the Heart’s Electrical Activity
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.)
Holter or Event Monitor
Figure A shows how a Holter or event monitor attaches to a patient. In this example, the monitor is clipped to the patient’s belt and electrodes are attached to his chest. Figure B shows an electrocardiogram strip, which maps the data from the Holter or event monitor.
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.
Too much movement can pull the patches away from your skin or create “noise” on the ECG (electrocardiogram) strip. An ECG 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.
Keeping a Diary
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:
• Fainting or feeling dizzy.
• Palpitations. These are feelings that your heart is skipping a beat, fluttering, or beating too hard or fast. You may have these feelings in your chest, throat, or neck.
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.
What To Expect With Specific Monitors
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. Your cardiologist will discuss the result with you on the day of your next appointment.
(Reference : https://medlineplus.gov/ency/article/003877.htm)