Ambulatory electrocardiography (EKG or ECG) monitors the electrical activity of your heart while you go about your daily life. Because many heart problems occur only during certain activities, such as exercise, eating, emotional stress, or sleeping, a continuous, 24-hour recording is much more likely to detect any abnormal heartbeats occurring under these circumstances.
Ambulatory monitoring is done in order to:
- Detect irregular heartbeats, or arrhythmias, that occur intermittently or during certain activities.
- Evaluate symptoms of possible heart disease such as chest pain, palpitations, dizziness, or fainting.
- Detect poor blood flow to your heart muscle (ischemia), which may indicate coronary artery disease (CAD).
- Monitor the effectiveness of treatment, such as medication or a pacemaker for abnormal heart rhythms.
There is no risk associated with ambulatory monitoring. The electrodes placed on your skin only detect the electrical signals from your heart. No electricity is sent through your body, and there is no possibility of receiving an electric shock.
The most common type of ambulatory monitoring is called Holter monitoring, which involves wearing a device that records continuous electrical signals from your heart for 24-72 hours. While wearing the monitor, you will also keep a daily journal of your activities and symptoms.
Many people have irregular heartbeats, but because these abnormalities are periodic, they may be difficult to observe during an office visit. For example a standard, in-office EKG only monitors 40-50 heartbeats. A Holter monitor, however, records about 100,000 heartbeats in 24 hours and is much more likely to detect a problem.
What to Expect During Holter Monitoring
In preparation for using the Holter monitor, it is a good idea to shower or bathe because you will not be able to do so during the recording period. Wear a loose-fitting blouse or shirt.
In our office, a technician will fit a lightweight, battery-operated tape recorder (monitor) on a strap over your shoulder or around your waist. Several areas on your chest may be shaved and cleaned, and a small amount of electrode gel will be applied to those areas. Several electrode pads (which detect the signals from your heart) will then be attached to your chest, with thin wires connecting the electrodes to the monitor. You will also receive a blank journal to write down any symptoms you have during the monitoring period, including the type of activity you were engaging in and the time your symptoms occurred.
You then leave our office to resume normal daily activities while wearing the monitor. In the journal, write the exact times when you exercise, climb stairs, eat, urinate, smoke cigarettes, sleep, get emotionally upset, take medications, or engage in other activities. If you have any symptoms of heart problems (such as dizziness, fainting, chest pain, or palpitations) push the event-marker button on the Holter monitor and write the exact time and duration of the symptom. For example, you might write: “1:00 p.m. Argument with boss, had chest tightness for several minutes.” The accuracy and effectiveness of this test depends on how carefully you record your activities and symptoms and the times they occurred in the journal.
Overnight, try to stay on your back with the recorder carefully positioned at your side to ensure that the electrodes stay in place. If one of the electrodes or lead wires becomes loose, a light on the monitor will flash. Press on the center of each electrode to see if you can restore the contact. If one of the electrodes comes off and you have difficulty replacing it, call us.
At the end of the recording period (usually 24 hours), you will either return to the office to have the electrodes removed or, if you’ve been taught how, you may remove the electrodes yourself. A computer will analyze the recorded tape to provide information about your heart rate, the frequency of heartbeats, and any abnormalities. Your doctor will compare the timing of the activities and symptoms written in your daily journal with the heart patterns recorded by the monitor.
Cardiac Event Monitor
Another kind of ambulatory monitoring is called cardiac event monitoring. This can be used when symptoms of an abnormal heart rhythm occur infrequently. A cardiac event monitor can be used for a longer time than a Holter monitor and is more likely to record an abnormal heart rhythm that occurs less frequently. The information recorded by a cardiac event monitor is sent over the phone to our office.
What to Expect During Cardiac Event Monitoring
The procedure for cardiac event monitoring depends on the type of monitor used. Electrodes will be attached to your chest in the same way as a Holter monitor, and you will be instructed to start the recorder when you have symptoms of a heart problem.
The sites where the electrodes are on the chest may itch slightly during the recording, and the skin may become slightly irritated when the electrodes are removed. The recording unit is very lightweight, so carrying it usually is not problematic.