What is an Implantable Loop Recorder?
- The Electrocardiogram (ECG) is a routine test which aids in the recording of the electrical activity of heart. ECG alone is not adequate in patients who experience arrhythmias less frequently.
- Holter Monitoring helps in the continuous electrocardiographic (the graphical record of electrical heart activity) recording for 24-48 hours or more.
- Cardiac event recorder is a portable external device, which helps to record the electrical activity of the heart whenever the patient experiences the symptoms. Cardiac event monitor helps to detect the arrhythmias, which occur less than daily.
- Implantable Loop Recorder (ILR) is an implantable device that can be used in patients with arrhythmias, which occur once in months or year.
What are the Uses of ILR?ILR is useful in patients who present with the following symptoms and when ECG, 24 hour Holter monitor or a 30-day event monitor are not enough to capture the problem because of the less frequent occurrence.
- Recurrent Unexplained Syncope: Syncope is temporary unconsciousness. It can be due to multiple reasons. Cardiac causes of syncope are arrhythmias, obstructed blood flow within the heart, heart failure, myocardial infarction, diseases of the valves of the heart, cardiomyopathies, aortic stenosis or blood clot. The diagnostic tests like electrocardiogram and echocardiogram can help to detect the underlying cause of the cardiac syncope. ILR is useful in recurrent unexplained syncope.
- Recurrent Palpitations: In patients with infrequent unexplained palpitations, ILR is safe and cost effective diagnostic option.
- Cryptogenic Stroke: ILR is found to be useful in patients with unexplained stroke (decrease in the blood supply to the brain) due to undetected atrial fibrillation.
- Atrial Fibrillation: In patients with Atrial Fibrillation ILR can be used as a monitoring device.
How does the ILR work?ILR records the electrical heart activity. It works by two ways.
ILR monitors the heart rhythm and records any rhythm that crosses the set threshold parameters in the device. ILR records both the tachyarrhythmias (abnormal increase in the electrical heart activity) and bradyarrhythmias (abnormal decrease in the electrical heart activity).
ILR also records the electrical heart activity when the patient triggers the patient activator. The patient should trigger the activator after placing it close to the chest and near the ILR. The patients are instructed to trigger when they experience lightheadedness, dizziness or skipped beats.
How is ILR placed?The implantation of ILR is performed in the hospital. It is done under complete aseptic precautions and local anesthesia. The area left to the breastbone and below the collar is cleaned sterile. A local anesthetic agent is injected at the incision site. A skin incision of about 1-2 cm is made, and a pocket is created below the skin to hold the device. ILR is placed in the pocket; skin is sutured and dressed. It takes around 20-30 minutes to implant ILR.
What to Expect after the Procedure?
- The discharge is usually on the same day of the procedure.
- The doctor usually suggests the patient for a check-up after 1-2 weeks to make sure that the incision has healed. Later, the patient will be asked to visit once every three months.
The device will be programmed to a threshold heart rate level to detect the low and high heart rates. It will be programmed to detect the arrhythmias.
- The device records when the heart rhythm reaches the set programmed parameters and also when the patient triggers the activator.
- The device check is called interrogation. Interrogation can be done at physicianís office or remotely from the patientís place.