Implantable Loop Recorders

Implantable device for diagnostics of sporadic faintings or palpitations

Implantable loop recorder Medtronic Reveal can help in establishing whether symptoms such as dizziness, blackouts and palpitations have a cardiac cause. Syncope, or blackout, is often difficult to diagnose as episodes are often too infrequent and unpredictable. Unlike conventional ECG monitoring (such as 24-hour ECG monitor or event monitors), loop recorder monitors heart rhythm continuously for up to three years, so that the likelihood of capturing ECG during the episode of is greatly increased. ILR works much like a black box in an airplane, whereby vital information is recorded during the actual episode and can be played back later for detailed analysis. To store the heart rhythm, also known as ECG, a patient needs to place a special activator over the implanted recorder and press a button. The device also can store rhythms automatically when patients are unable to use the activator or when patients are asymptomatic.

Syncope may have many different reasons and arrhythmic causes (abnormal heart rhythm) are the most serious, with the risk of cardiac arrest and death, therefore reliable diagnosis is of paramount importance. When heart rhythm is recorded during an actual episode, analysis will show either normal ECG which means that the cause is not related to arrhythmia or the ECG is abnormal confirming arrhythmic cause. In either case, the diagnosis will have been achieved and the device can be removed. If the episodes are caused by an abnormal heart rhythm, treatment options include medication, a pacemaker or implantable cardioverter-defibrillator (ICD), or catheter ablation. After these treatments, patients can often resume normal activities without fear of suffering another episode.

ILR implants are performed at the Lister Hospital as day cases, i.e. you will go home the same day. You may not drive home, so please arrange someone to collect you.

Indications

Recurrent unexplained syncope (blackout) following a negative baseline work-up in patients who require further investigations because of complications.

Recurrent unexplained syncope (blackout) before conventional testing in patients with clinical or ECG features suggesting an arrhythmic syncope.

Assessment of contribution of bradycardia (abnormal slow heart beat) in suspected cases of severe neurally mediated syncope (a type of blackout caused by low blood pressure) before pacemaker implantation.

Diagnostics of atrial fibrillation (AF) before and after ablation procedures.

Risks and complications

The procedure is safe and the risk of complications (approx. 1%) if offset by the benefit of having a correct diagnosis and subsequently appropriate treatment. Complications include wound infection, wound haematoma (collection of blood under the skin), device erosion through the skin and device migration.

Before the procedure

You will need a blood test about a week before the procedure. Anticoagulants, i.e. blood thinning drugs (warfarin, sinthrome) and clopidogrel will need to be stopped 5 days before the procedure. You can drink water, clear tea and black coffee (without milk) up to 2 hours before the procedure. Milk, food, sweets, tea or coffee with milk can be taken up to 6 hours before the procedure. Chewing gum and smoking not permitted on day of surgery. Please take all your regular medication (except diabetic medication and insulin) as usual with a sip of water. Please bring the actual list of medication including dosage with you. I will explain the procedure to you and any questions you may have can be answered at this time prior to you signing the consent form for the procedure. A small needle will be put in your arm. Your heart rhythm and oxygen saturation (level of oxygen in blood) will be monitored throughout procedure. Shaving near the implant site may be required.

Risks and complications

ECG is noninvasive procedure and there are no known risks with this investigation. Should you have any worries about the procedure Dr Kirk will be only too pleased to discuss them with you.

Before the procedure

You will be taken into the room where the test is to be performed. The test will be explained and you will be asked to remove any necessary articles of clothing above the waist. Since access to your ankles is needed, it is helpful if ladies could avoid wearing tights. Some electrode pads will be stuck onto your chest and limbs to which wires going to the ECG recorder will be attached. It is helpful for this test if you can remove any jewellery from your neck before you arrive.

During the procedure

Implanting the loop recorder takes about 20-30 minutes and is done under a local anesthetic and sometimes with a small dose of sedation to keep you relaxed and comfortable. You will have a small injection to numb the skin and then will make a small wound about 2 cm on the left side of the chest. I will create a pocket for the ILR, about the size of a memory stick. The wound will be closed with absortable suture (i.e. nothing will have to be removed) and usually skin closed with special glue. The implanted loop recorder will be covered with dressing. Once the device is inserted in the pocket, it is programmed to record the ECG.

After the procedure

After the procedure, you will be able to eat and drink and allowed to leave hospital after 30-60 minutes of recovery. You won’t be able to drive and will need to arrange your transport. You can return the following day to your normal work or activity. Fitness to drive will depend on your symptoms and should be discussed with me.

You must not have MR (magnetic resonance) scan. Any strong magnetic field can affect your loop recorder. You need to avoid arc-welding and metal detectors. Ask to be hand searched in a security checks, such as on an airport. Keep the wound dry and covered with dressing for 7 days; afterwards the dressing can be removed and you can take a shower or bath. Symptoms that you must report immediately to Dr Kirk: fever, tenderness, redness or swelling of the wound, oozing or bleeding from the wound, breathlessness, palpitations, dizziness, lightheadedness or blackout. The first follow-up visit will be 1 month after discharge. After that, appointments will be every 6 months or in case of any symptoms.