Holter monitoring is a medical procedure in which a patient wears a portable, external cardiac monitor over a period of time, usually between 24 and 72 hours. The heart monitor continuously records the electrical activity of the heart during this time period. The procedure is very similar to an electrocardiogram, or EKG. The main difference is that a Holter monitor is portable, so it can measure the heart rate while the patient is going about their daily activities.
Holter monitoring is used most commonly to detect heart arrhythmias. Heart arrhythmia refers to any problems with the rate or rhythm of the heartbeat, including a heartbeat that is too fast, too slow, or irregular. Doctors use Holter monitors to detect heart problems in the early stages, sometimes even before the patient has any noticeable cardiac symptoms. Holter monitoring may also be used to determine if an ongoing cardiac treatment plan is effective, or if changes need to be made.
Holter monitoring is a painless procedure that is usually begun in the doctor's office. Electrodes are attached to the skin on the chest using sticky patches, tape, or special electrode adhesive. The electrodes are then connected to the cardiac monitor, a small device that can be clipped to your belt or carried in a pouch over your shoulder. The monitor continuously records the electrical activity in your heart while you go about your daily activities. You may be asked to refrain from showering and any activity that will cause excessive sweating, as this may cause the electrodes to fall off, as well as cause damage to the monitoring equipment.
Patients who are wearing a Holter monitor are usually asked to keep a diary of their symptoms. This includes recording the time of any episodes of palpitations or flutters, dizziness, or any other unusual symptoms. You may also be asked to note times when you are under stress or agitated, or participating in physical activities. By comparing your diary with the results of your heart monitor, your doctor can get a more complete picture of how your heart is responding to both physical and emotional events in your daily life outside of the clinic. Your doctor will give you detailed instructions regarding your particular monitor and diary.
After your testing period is over, you will return to the doctor's office or hospital with the monitor and your diary. The data recorded by the monitor will be uploaded to a computer and analyzed by your doctor or other specialist. It may take several days for your results to be finalized. Your doctor will discuss your test results with you and develop a treatment plan if necessary.