Ambulatory Rhythm Monitoring (Holter and Event Recorders)


Ambulatory rhythm monitoring is a tool that your physician can use in order to help diagnose slow or fast heart rates. Normally the heart beats between 60 and 100 beats per minute. Heart rates that are slower or faster may be relatively benign requiring no specific treatment but may also represent significant underlying heart disease. Symptoms can manifest themselves as fatigue, lightheadedness, passing out or feeling the heart racing or pounding in the chest. Monitoring the heart will provide your physician with an EKG to help diagnose if the heart is beating abnormally. Since these rhythms can be very brief and episodic, prolonged monitoring may be necessary.

Holter monitoring is the most common type of heart monitor. This basically consists of the patient wearing 3-5 leads on the chest connected by wires to a box that the patient can wear on their belt. The device is worn for 24-48 hrs and records a continuous electrocardiogram for the entire time period. A diary is given to the patient to record any heart-related symptoms that they experience. After the device is returned and processed, all of the heart beats are studied for abnormalities and any symptoms are reviewed to see if they correlate with arrhythmias. Because holter monitor is used for 24-48 hrs, it is best used for patients who have daily symptoms.

Other times a patients symptoms may be quite infrequent and unpredictable. In these cases longer monitoring is needed. If symptoms are very brief, a looping event recorder or Cardionet® monitor is used. These are similar to a holter monitor but can be worn for 21-30 days. It continually records all of the heart beats but automatically "saves" any unusually fast or slow rhythms in addition to saving the heart recording when the patient pushes a button on the device during any symptoms they experience. The leads can be taken off in the shower and other situations but should be worn as much as possible in order to give the best chance of recording an unpredictable, brief rhythm or symptom.

If symptoms are episodic but somewhat prolonged, lasting more than a few minutes, then a non-looping recorder can be used. This device can be used for 30 days but does not have any wires. During symptoms the patient simply places their thumbs on the contacts of the device and an EKG will be recorded and stored. While this device is less cumbersome than a wired device, symptoms must last long enough and requires more patient participation for the patient to use the device correctly.

If symptoms are too brief and/or infrequent to be recorded using the above devices for 30 days, an implantable loop recorder (Reveal®) can be used. This device weighs 17 grams and is 61x9x8mm. It is placed surgically under the skin through a 3/4 inch incision usually below the collar bone on the left side. The procedure is performed under local anesthesia and takes about 15-20 minutes. Once implanted, the device can be left in place for up to 14 months and can be interrogated non-invasively with a special computer for any rhythm abnormalities.

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