CARDIAC HOLTER MONITOR
Many people have occasional irregular heartbeats which are commonly referred to as arrhythmias. Whether these arrhythmias are important or not depends on four main criteria:
i) The type of arrhythmia.
ii) The frequency of their occurrence.
iii) How long they last.
iv) Whether they occur at the same time you have symptoms.
A Holter monitor records the electrical activity of your heart while you do your usual activities. Many heart problems become noticeable only during activity, such as exercise, stress, eating, sleeping, or even sex. A continuous 24-48 hour recording is more likely to detect any abnormal heartbeats that occur during these activities.
Since a standard ECG only monitors 40 to 50 heartbeats during the brief period you are attached to the machine, a Holter monitor is more likely to find any heart problems that happen with activity since it monitors over 86,000 heartbeats in 24 hours.
SYMPTOMS ASSOCIATED WITH AN ARRHYTHMIA
- Irregular Heart Beat (Atrial fibrillation)
- Irregular Heart Beat (Atrial flutter)
- Dizziness
- Chest Pain
- Light-headedness
- Loss of consciousness (pre-syncope, syncope)
- Fast heartbeat (Palpitations)
- Fast heartbeat (Paroxysmal supraventricular tachycardia)
- Fast heartbeat with dizziness (Paroxysmal ventricular tachycardia)
- Premature / extra heartbeats
- Shortness of breath, dyspnea
HOW HOLTER MONITORS WORK
Much like standard electrocardiography, the Holter monitor records electrical signals from the heart via a series of electrodes attached to the chest. Electrodes are placed over bones to minimize artifacts from muscular activity. The number and position of electrodes varies by model, but most Holter monitors employ between three and eight. These electrodes are connected to the recorder that is attached to the patient’s belt or hung around the neck, and is responsible for keeping a log of the heart’s electrical activity throughout the recording period.
WHY HOLTER MONITORING?
A Holter monitor is prescribed for four main reasons:
i) Record irregular heartbeats that occur intermittently or during certain activities.
ii) Find out what is causing chest pain, fainting or dizziness. These are symptoms of possible heart problems.
iii) Look for poor blood flow to your heart muscle (ischemia).
iv) Check to see if treatment for an irregular heartbeat is working.
PROCEDURE
A lightweight, battery-operated monitor is either put in pouch and hung around the neck or clipped to the waist. The recorder is connected by wires to small metal discs (electrodes) taped to the chest. The electrodes detect the electrical signals from the heart.
The recorder and electrodes are fitted by a technician in a doctor’s office or hospital room.
i) Several areas on the chest may be shaved and cleaned, and then a small amount of electrode paste or gel will be applied to those areas.
ii) The electrode pads will then be attached to the skin of the chest, with thin wires connecting the electrodes to the monitor.
It is important while wearing the continuous recorder, to keep a diary of all activities and symptoms, including the type of activity and the time symptoms started.
At the end of the recording period (usually 24 or 48 hours), the device is returned to he doctor’s office or hospital to have the electrodes removed. The data will be read by computer to provide information about the heart rate, the frequency of heartbeats, and any irregularities.
After the monitoring period, the doctor will compare the timing of activities and symptoms with the recorded heart pattern. The accuracy and usefulness of this test depend on how carefully the activities and symptoms and the times they occurred were recorded.
HOW IT FEELS
Sometimes with patients with sensitive skin, the electrode sites may itch slightly after 48 hours of monitoring. The Holter monitor is very lightweight, so carrying it usually is not uncomfortable.
RISKS
There are no risks from Holter monitoring. The electrodes placed on your skin detect only the electrical signals from your heart. No electricity is sent through your body, and there is no possibility of receiving an electric shock.
INTERPRETATIONS
Results of Holter monitoring usually are interpreted by a cardiologist and are generally available in a few days.
Normal: No abnormal heart rhythms are found in the ECG information collected by the recorder.
Abnormal: Many kinds of irregular heartbeats can be detected by Holter monitoring:
- Abnormal slow or fast heart rhythms are detected. Alternating slow and fast rhythms may also occur occasionally.
- A slow heart rhythm in a person with a pacemaker may mean that the pacemaker is not working correctly.
- Abnormal patterns may mean that the heart muscle is not getting enough oxygen (ischemia) because the arteries feeding the heart are too narrow.
