A tiny implantable heart monitor for diagnosing sporadic faintings or palpitations
An implantable loop recorder can help establish whether symptoms such as dizziness, blackouts and palpitations have a cardiac cause. It can be difficult to determine if these symptoms are due to heart rhythm problems if they occur only infrequently. Unlike conventional ECG monitoring (such as 24-hour ECG monitor or event monitors), the loop recorder monitors heart rhythm continuously for up to three years so that the likelihood of capturing ECG during symptoms is greatly increased. ILR works much like a black box in an aeroplane, whereby vital information is recorded during the actual episode and can be played back later for detailed analysis.
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, the relevant ECG will either normal ECG, which means that the symptoms are not due to a heart rhythm problem, or the ECG will be abnormal, confirming arrhythmic cause. We will have achieved a diagnosis in either case, and it will be possible to remove the device. If an abnormal heart rhythm causes the episodes, treatment options include medication, a pacemaker, implantable cardioverter-defibrillator (ICD), or catheter ablation. After these treatments, patients can often resume normal activities without fear of suffering another episode.
The procedure is safe, and the risk of complications (approx. 1%) is offset by the benefit of having a correct diagnosis and subsequent appropriate treatment. Complications include wound infection, wound haematoma (blood collection under the skin) and device migration.
You will need a blood test about a week before the procedure. Anticoagulants, i.e. blood-thinning drugs (warfarin, apixaban, edoxaban, rivaroxaban, dabigatran) 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. You can consume milk, food, sweets, tea or coffee with milk up to 6 hours before the procedure. Chewing gum and smoking is not permitted on the 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. Dr Ruzicka will explain the procedure to you and answer any questions you may have before signing the consent form for the procedure. A small needle will be inserted into your arm. Your heart rhythm and oxygen saturation (oxygen level in the blood) will be monitored throughout the procedure. Shaving at the implant site may be required.
Implanting the loop recorder takes about 20 minutes and is done under a local anaesthetic and sometimes with a small sedation dose to help you relax. You will receive a small injection to numb your skin. The loop recorder, which is about the size of a memory stick, will be then inserted under the skin. The wound will be closed with absorbable suture (i.e. nothing will have to be removed), and the skin will be closed with special glue. The implant site will be covered with a dressing.
After the procedure, you will be able to eat or drink and allowed to leave the hospital after approximately 60 minutes of recovery. You will need to arrange your transport from the hospital because you will not be able to drive for 24 hours after the procedure. You can return the following day to your normal work or activity. Fitness to drive will depend on your symptoms, and Dr Ruzicka will discuss it with you. The wound should be kept dry and covered with a dressing for 7 days; afterwards, the dressing can be removed, and you can take a shower or bath. You will receive a follow-up appointment with one of the physiologists at the Alexandra Hospital.