Under certain circumstances the beat of the heart can become abnormally fast in a very dangerous way. This usually occurs in people who already have major abnormalities of the electrical system of the heart or of the heart muscle. An Implantable Cardioverter Defibrillator (ICD) can detect such fast heartbeats and correct them by applying a series of electrical impulses to the heart or by delivering a shock to the heart.
An ICD is made up of a pulse generator, which lies under the skin just below the collarbone (usually), and 1 to 3 leads that arise from the pulse generator and go into the heart. The leads transmit the electrical impulses or shock from the pulse generator to the heart muscle.
PROCEDURE: WHAT IS INVOLVED IN ICD IMPLANTATION?
ICD insertion is a common procedure. This is performed under local anaesthetic with sedative medication to make you feel comfortable. The procedure takes approximately 1-2 hours and is performed in the cardiac catheter laboratory. This is a special room that has a patient table, X-Ray tube, ECG monitors and other equipment. The staff in the lab will all be dressed in hospital theatre clothes and during the procedure will be wearing hats and masks. Many ECG monitoring electrodes will be attached to your chest area. A nurse or doctor will insert an intravenous line usually into the back of your hand. This is needed as a reliable way to give you medications during the study without further injections.
You will also have a blood-pressure cuff attached to your arm that will automatically inflate at various times throughout the procedure. There will also be considerable attention at cleaning the skin under the collarbone where the ICD will be inserted. You will also receive antibiotics prior to the procedure. You should ensure that you inform the Doctor if you have any allergies.
The ICD is inserted just under the collarbone. The area is prepared with a special sterile solution that may feel cold. A large sterile sheet that will partly cover your face will cover you. You will be able to look out from under the sheet to the side and a nurse will be present at all times. You will be given oxygen to breathe by a small tube that is positioned under your nostrils.
At the start of the procedure, the doctor will inject local anaesthetic into the area under the collarbone where the ICD is to be inserted. This will sting momentarily but the area will then be numb. During the procedure you may feel some firm pushing in the shoulder area but this should not be painful. If you experience pain or discomfort you should tell the nurse or doctor. At the end of the procedure a fast heart rhythm will be induced and the effectiveness of the ICD will be tested. For this testing you will receive stronger sedation or occasionally a general anaesthetic. It is unlikely that you will remember much of the procedure.
After the procedure you will have some bruising and discomfort in the area of the pacemaker that may persist for several weeks. You should avoid strenuous activities with your arm for a period of 4 weeks. If the ICD is implanted without previous rhythm disturbance (primary prevention) you are legally required to refrain from driving for 2 weeks after the procedure. If the ICD is implanted after previous rhythm disturbance (secondary prevention) you are legally required to refrain from driving for 6 months and then after clearance by your Doctor.
You will be allowed to go home 1 or 2 days after the procedure.
ICD INSERTION RISKS
Procedural risks of ICD implantation are summarised below:
- All patients will be left with a scar and an ICD (which can usually be felt) under the skin.
- Most patients will have some initial bruising. If you are taking aspirin, clopidogrel, warfarin or other “blood thinners” the bruising may be significant.
- 1 in 40 – The ICD leads can move after the procedure – this may require a repeat procedure to fix the problem.
- 1 in 100 – An infection may arise at the ICD site. This is a difficult problem to treat and may require the ICD to be removed.
- 1 in 100 – A lung may collapse. This may require the insertion of a tube to reinflate the lung.
- 1 in 200 – A blood clot may form in the subclavian vein. This is the vein that the leads go through to get to the heart.
- 1 in 1000 – The leads may puncture the heart muscle, giving rise to cardiac tamponade; which may be fatal.
- 1 in 1000 – A blood clot can form in the legs and go to the lungs. This may be fatal.
- Rare – It is possible although rare to have a life threatening allergic reaction to a medication, a stroke, heart attack or die as a result of an ICD insertion.
Obviously every effort is made to minimise the risks of the procedure and you should be aware that emergency equipment is available to deal with any complications that occur.
It is important to understand that these are average risks. Your individual risk may be higher or lower depending on a number of factors such as your age and general health. Your cardiologist knows these risks and has considered them before recommending that you undergo an ICD implantation.