Implantable Loop Recorder (ILR)

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Implantable Loop Recorder (ILR)

Patients may have unexplained recurrent symptoms of dizziness, palpitation or loss of consciousness. There are many causes, such as arrhythmias (abnormal heart rhythm). Sometimes, a definitive diagnosis cannot be made after conventional investigations.

Implantable loop recorder (ILR) is used to check whether the symptoms are due to arrhythmias. It is a small device implanted usually under the skin of the left chest wall. It consists of 2 internal electrodes, through which the heart rhythm can be monitored. The battery can last for >12 months.


  • This invasive procedure is performed under local anesthesia in the Cardiac Catheterization & Intervention Laboratory (CCIL). You are alert during the procedure, but we may give you sedation to calm you down.
  • A small incision (about 2 cm long) is made over the left chest wall.
  • The ILR is inserted through the incision into the pocket underneath the skin.
  • The wound will be closed with suturing material and covered with dressing.
  • The procedure usually takes about 20-30 minutes.

After Surgery:

  • You may be discharged from hospital on the day or 1 day after the ILR implantation.
  • The wound should be covered with light dressing. Please keep the wound site clean and avoid making the dressing wet during a bath. Always change dressing if wet.
  • You may need to come back to the centre for suture removal 1 week after the procedure. You may remove the dressing 2-3 days after suture removal.
  • Follow your doctor’s instructions or refer to the information booklet from the ILR company to minimize the risk of electromagnetic interference. In general, strong electro-magnetic field or radiofrequency signal will interfere your ILR. Please keep a distance of >15 cm (6 inches) from an active mobile phone. Household electrical or electronic appliance usually does not affect ILR.
  • Depending on the type of ILR used, you may be given a hand-held activator for recording of events. We will explain to you how to operate.
  • When a cause is found using the device, we may remove the ILR and give you the appropriate treatment accordingly.
  • When battery is depleted, it can be removed or replaced as decided by your doctor.