Implantable Loop Recorder

What is an implantable loop recorder?

An implantable loop record (ILR), also known as an implantable cardiac monitor (ICM), is a device used to monitor fast, slow or irregular heart rhythms. The devices are about 4cm long, 0.5cm deep and weigh around 10 grams. They are implanted underneath the skin, usually on the left side of your chest. They can record electrical activity in your heart for up to three years, on a constant loop (hence the name).

Why would I need one?

Loop recorders can be helpful if standard heart rhythm monitoring or an electrocardiogram (ECG) test hasn’t been able to explain the symptoms you’re experiencing.

It could also be that your symptoms only occur occasionally or intermittently, so they haven’t been picked up during short-term monitoring. Capturing data over a longer period can help us to work out what might be causing the issues.

How does the recorder work?

It works in a similar way to external monitoring devices, but over a much more sustained period. The recorder detects electrical signals from your heart and stores the data so we can review it later. We can download this data through a mobile phone or through a dedicated home monitor as well; this is an external device that collects data directly from your loop recorder and transmits it automatically to the Cardiology department. It needs to be plugged in and placed next to your bedside, no further than 2m away from you.

Home monitors also allow you to send data manually to the hospital in an emergency if you experience any particularly concerning symptoms.

Can I use the standard recorder to make a note of my symptoms when they occur?

Yes. Alongside the recorder, you’ll also receive a symptom activator. This is a hand-held key fob device which lets you mark when you’re experiencing a symptomatic event, such as dizziness, fainting, palpitations, loss of consciousness, skipped beats, or a racing or fluttering heart. You should always keep it with you.

To use the activator, simply raise it to your chest, then press and release a button to confirm connection with the loop recorder; a flashing light tells you when the device has been found by your recorder, and when you can remove it from your chest.

The aim of the activator is to work out whether the symptoms you experience are being caused by your heart or by something else. Activators don’t start or stop the ongoing recording of your heart data. They simply act as a manual “highlighter” for your symptoms, to give us a little more information about the rhythm issues.

How would you implant the recorder?

Fitting a loop recorder is a simple process. It usually takes about 10-15 minutes and can be done as a day case appointment. When you come into the clinic for the fitting, we’ll give you a local anaesthetic to numb the area of skin around your chest. We’ll then make a small incision in your skin (about 0.5cm wide) and insert the device under your skin, before closing the cut with a special kind of medical glue.

You should be able to go home as soon as we have dressed the wound. Before you leave, we’ll give you a booklet with information about your loop recorder, how it works and how to use it with the symptom activator.

We will also give you an ID card detailing the type of device that has been fitted. You should keep the ID card with you at all times in case of an emergency.

What happens next?

After the fitting, you may need to avoid stressing your upper body so you can give the cut time to heal. There may be some bruising in the area, and it may feel slightly sore for the first few days. We may recommend you keep the dressing dry for up to a week afterwards.

If you notice any swelling, itching, redness or signs of infection, or if you feel the device moving, you should contact the Cardiology department at the hospital straight away. If these symptoms occur out of hours, you should attend your local emergency department or GP practice.

Once the wound has healed, you should be able to go back to your normal everyday activities. Having an implantable loop recorder shouldn’t stop you from doing anything you did before, such as driving, playing sport, or going to the gym.

Can I have MRI, CT scans or X-rays if I have an implantable loop recorder?

Yes, but you’ll need to let the relevant medical team know beforehand that you have one in situ and bring your device ID card along to the appointment. When travelling, it’s safe to pass through airport security scanners, but you should make sure you have your ID card ready in case the device triggers the metal-detecting machines.

Can household electrical items interfere with a loop recorder?

No, your device is protected from external interference. It won’t be affected by microwaves, induction hobs, mobile phones, and other household items.

When and how will you remove the loop recorder?

We can usually remove the recorder once it has given us enough data to make a firm diagnosis.

As with the implantation, it’s a simple process to remove the device. When you come in for an appointment, we’ll give you a local anaesthetic to numb the area. We’ll then make an incision along the line of the original cut, carefully slide out the device, and close and dress the wound.