Implantable Loop Recorder (ILR) Information

What is an Implantable Loop Recorder? 

An Implantable Loop Recorder (ILR) is a small cardiac monitoring device placed just under the skin of your chest. The device continuously records your heart’s electrical activity and helps detect abnormal heart rhythms (arrhythmias). 

The recorder is very small—similar in size to a slim USB memory stick—and sits comfortably beneath the skin where it cannot normally be seen. It does not deliver treatment or change your heart rhythm; its purpose is simply to monitor and record information about how your heart is beating.  

Doctors often recommend an ILR when symptoms such as fainting, palpitations, dizziness, or unexplained blackouts occur but cannot be diagnosed using short-term monitoring tests like ECGs or Holter monitors. Because it can monitor your heart for months or years, it is especially useful for detecting irregular heart rhythms that happen only occasionally. 

How does it work? 

The ILR continuously monitors your heart’s electrical signals and records information about your heart rate and rhythm. 

Recordings can be saved in two ways: 

• Automatic recording: The device is programmed by your doctor to detect abnormal heart rhythms such as very fast or very slow heart rates. When these are detected, the device automatically records the event. 
• Manual recording: If you experience symptoms such as dizziness, palpitations, or fainting, you can activate a recording using your Patient Assistant device. 

The Patient Assistant is a small handheld device that should be carried with you at all times. When symptoms occur, placing it over your chest will trigger the recorder to save the heart rhythm around the time of the event. This allows your doctor to compare your symptoms with your heart rhythm at that moment.  

Your cardiologist will review the stored recordings to help diagnose heart rhythm disorders or determine whether your symptoms are related to another cause. 

How long will I have my ILR? 

Your cardiologist will decide how long you need the loop recorder. 

Most devices have a battery life of approximately 3 to 4 years, allowing long-term monitoring of your heart rhythm.  

The device may be removed earlier if: 

• A diagnosis has been made 
• Your symptoms have resolved 
• The battery reaches the end of its life 

Removal is a simple procedure similar to the original implantation. 

How is the ILR implanted? 

The ILR is inserted as a day-case procedure. 

Although the procedure itself usually takes about 30 minutes, you will be asked to arrive approximately 45 minutes before your appointment so you can be admitted to the Day Unit. After the procedure you will remain for around one hour of monitoring before going home. 

The procedure involves: 

1. Local anaesthetic being injected to numb the skin on your chest. 
2. A small incision (about 1 cm long) being made just under the skin. 
3. The ILR being inserted under the skin. 
4. The incision being closed with a stitch or steri-strips. 

The device sits in a small pocket beneath the skin and does not interfere with your daily activities.  

Who will perform my procedure? 

Your ILR will be implanted by a Cardiology Consultant, assisted by a nurse or healthcare assistant and Cardiac Physiologist. 

After the procedure, a member of the Cardiac Investigations Team will explain how to use your Patient Assistant device and answer any questions you may have. 

What are the risks?

Implantation of a loop recorder is considered a very safe and low-risk procedure, but as with any minor surgery there are some potential complications. 

Possible risks include: 

• Infection at the implant site 
• Bleeding or bruising 
• Mild discomfort or soreness around the wound 
• Rarely, movement of the device under the skin  

These complications are uncommon and most patients recover quickly. 

You will receive instructions about wound care and signs to look out for after your procedure. 

After the procedure 

Most patients go home the same day after a short period of monitoring. 

You may: 

• Drive home if you feel well, although some discomfort at the implant site is possible. 
• Prefer to arrange alternative transport if you feel sore. 

You can usually return to normal daily activities soon after the procedure, but it is recommended that you: 

• Avoid heavy lifting 
• Avoid strenuous upper-body exercise 
• Avoid excessive stretching or strain 

for about one week to allow the wound to heal. 

Some mild bruising or tenderness around the incision site is normal and should settle over the following weeks. 

You will be seen again approximately 4 weeks after the procedure for a wound check and device review. 

How will my ILR be followed up?

Your ILR will be monitored remotely using your CareLink home monitor. 

This bedside monitor communicates wirelessly with your implanted device and automatically sends recorded information to the hospital for analysis. The monitor should be placed in your bedroom approximately 6–8 feet from your bed. 

The transmitted information is reviewed by your clinical team and reported to your Consultant Cardiologist, allowing them to assess your heart rhythm and identify any abnormalities. 

Who can I contact if I have questions? 

If you have any questions about the information in this leaflet, please contact: 

Imaging Department 📞 0208 949 8578 

Alternatively, you can speak directly with your Cardiologist.