What is an implantable loop recorder?
An implantable loop recorder is a tiny heart monitor, about the size of a paper clip, that is placed just under the skin of the chest. It continuously watches your heart rhythm for up to three or four years and stores any abnormal recording automatically; you can also mark a recording yourself when you feel unwell. It has no wires and does not treat the heart in any way, it only records.
Why is it done?
It is used when symptoms such as blackouts, near-fainting, dizziness or palpitations happen too seldom to be captured on a twenty-four hour Holter monitor. Because it listens for years rather than days, it can finally link a symptom to a rhythm, or reassure you that your rhythm was normal when the symptom occurred. It is also used to search for atrial fibrillation after an unexplained stroke, and to monitor a known rhythm problem or the effect of treatment.
What happens on the day?
This is a short procedure done in the catheterisation laboratory or a procedure room, usually as a day case. The skin over the left side of the upper chest is cleaned and numbed with local anaesthetic. A cut of less than a centimetre is made and the device is slid into place under the skin; the small wound is closed with a stitch or surgical strips and covered with a dressing. The whole thing takes about fifteen minutes and you are awake throughout. You will feel pushing or pressure but should not feel pain.
What to expect afterwards
You go home the same day. Keep the dressing dry for the first few days and avoid heavy lifting or vigorous arm exercise for about a week. There may be mild bruising and tenderness, and you will be able to feel the device under the skin; in slim patients a small bump is visible. You are given a small hand-held device or a smartphone link that sends the recordings to us automatically, often overnight, so that your rhythm can be reviewed without you coming in. Airport security, mobile phones and household appliances are safe; tell any doctor about the device before an MRI scan. When the battery ends or the question has been answered, the recorder is removed in an equally simple procedure.
Possible complications
Problems are unusual because nothing enters a blood vessel or the heart. Minor bruising, swelling or discomfort at the site is common and settles within days. A small number of patients develop an infection of the wound, which may need antibiotics or, occasionally, removal of the device. Rarely the device moves slightly under the skin, the skin over it becomes thin or irritated, or the wound heals with a noticeable scar. Some recordings are of poor quality or falsely flag a rhythm, which may mean extra reviews. Contact us if the wound becomes red, hot, swollen, painful or starts to leak.
This information does not replace a consultation. Please discuss your own risks and options with your cardiologist.