An implantable loop recorder (ILR), also known as an insertable cardiac monitor (ICM), is a small device that is implanted under the skin of the chest for cardiac monitoring, to record the heart's electrical activity for an extended period).Implantable Loop Recorder (ILR) System
with illustrations, Aurora Health Care

Operation

The ILR monitors the electrical activity of the heart, continuously storing information in its circular memory (hence the name "loop" recorder) as electrocardiograms (ECGs). Abnormal electrical activity -

arrhythmia Arrhythmias, also known as cardiac arrhythmias, heart arrhythmias, or dysrhythmias, are irregularities in the heartbeat, including when it is too fast or too slow. A resting heart rate that is too fast – above 100 beats per minute in adult ...

is recorded by "freezing" a segment of the memory for later review. Limited number of episodes of abnormal activity can be stored,Diagnostic assessment of recurrent unexplained syncope with a new subcutaneously implantable loop recorder

Oxford Journals Oxford University Press (OUP) is the university press of the University of Oxford. It is the largest university press in the world, and its printing history dates back to the 1480s. Having been officially granted the legal right to print books ...

, 2000 with the most recent episode replacing the oldest.The Implantable Loop Recorder: Current Uses, Future Directions
''The Journal of Innovations in Cardiac Rhythm Management'', 2011 Recording can be activated in two ways. First, recording may be activated automatically according to

heart rate Heart rate (or pulse rate) is the frequency of the heartbeat measured by the number of contractions (beats) of the heart per minute (bpm). The heart rate can vary according to the body's physical needs, including the need to absorb oxygen and excr ...

ranges previously defined and set in the ILR by the physician. If the heart rate drops below, or rises above, the set rates, the ILR will record without the patient’s knowledge. The second way the ILR records is through a hand-held "patient activator" whereby the patient triggers a recording by pushing a button when they notice symptoms such as skipped beats, lightheadedness or dizziness. The ILR records by "freezing" the electrical information preceding, during and after the symptoms in the format of an electrocardiogram. The technician or physician can download and review the recorded events during an office visit using a special

programmer A computer programmer, sometimes referred to as a software developer, a software engineer, a programmer or a coder, is a person who creates computer programs — often for larger computer software. A programmer is someone who writes/creates ...

Implantable Loop Recorder (ILR)

Brigham and Women's Hospital Brigham and Women's Hospital (BWH) is the second largest teaching hospital of Harvard Medical School and the largest hospital in the Longwood Medical Area in Boston, Massachusetts. Along with Massachusetts General Hospital, it is one of the two ...

or via online data transmission. Biotronik Remote Assistant III ILR patient remote controller

Uses

The ILR is a useful

diagnostic Diagnosis is the identification of the nature and cause of a certain phenomenon. Diagnosis is used in many different disciplines, with variations in the use of logic, analytics, and experience, to determine "cause and effect". In systems enginee ...

tool to investigate patients who experience symptoms such as syncope (fainting),

seizure An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much of the body with lo ...

s, recurrent

palpitation Palpitations are perceived abnormalities of the heartbeat characterized by awareness of cardiac muscle contractions in the chest, which is further characterized by the hard, fast and/or irregular beatings of the heart. Symptoms include a rap ...

s, lightheadedness, or dizziness not often enough to be captured by a 24-hour or 30-day external monitor. Because of the ILR's long battery life (up to 3 years), the heart can be monitored for an extended period. New devices are able to store a total of 60 minutes of recordings on their memory. Thirty minutes is reserved for automatic storage of arrhythmias according preprogrammed criteria. The remaining 30 minutes can be divided into a selectable number of slots for storage of manually triggered retrograde recordings as an answer to symptoms (fainting, palpitations etc.) which may be caused by an arrhythmia.

Insertion

The ILR is implanted by an electrophysiologist under

local anesthesia Local anesthesia is any technique to induce the absence of sensation in a specific part of the body, generally for the aim of inducing local analgesia, that is, local insensitivity to pain, although other local senses may be affected as well. It ...

. A small incision (about 3–4 cm or 1.5 inches) is made just lateral to the sternum below the nipple line, usually on the patient's left side.What is an ILR?
Good Samaritan Hospital (San Jose) A pocket is created under the skin, and the ILR is placed in the pocket. Patients can go home the day of the procedure with few restrictions on activities. Bruising and discomfort in the implant area may persist for several weeks. Patients are instructed in use of the activator, and advised to schedule an appointment with their physician after using it so that information stored in the ILR can be retrieved for diagnosis.

References

External links

Should you remove an implantable loop recorder after the diagnosis is made?

National Institutes of Health The National Institutes of Health, commonly referred to as NIH (with each letter pronounced individually), is the primary agency of the United States government responsible for biomedical and public health research. It was founded in the late ...

Contemporary Reviews in Cardiovascular Medicine: Ambulatory Arrhythmia Monitoring
'' Circulation'' {{Cardiac procedures Biomedical engineering Cardiac electrophysiology Diagnostic cardiology Implants (medicine) Medical devices Medical testing equipment

Operation

Uses

Insertion

See also

References

External links