Dispositivos ICD y CRT
ICD and CRT Device
ICD stands for implantable cardioverter defibrillator. If your doctor has suggested that you need an ICD you may have experienced or may be at risk of experiencing an abnormal, fast heart rhythm.
An ICD constantly monitors your heart rhythm and can deliver various electrical impulses to correct potential problems. It is made up of a small pulse generator, contains a battery and electronic circuits, and sophisticated leads that connect the generator to the heart. An ICD, like a pacemaker, is usually placed under the skin below your collarbone.
Most modern ICDs have three main functions:
If your heart rhythm is too slow, the device can give your heart extra support by working as a normal pacemaker (anti-bradycardia pacing).
If your heart beats too fast, the ICD can return your heart back to a normal rhythm (anti-tachycardia pacing or ATP).
If the anti-tachycardia pacing doesn’t bring your heart back to a normal rhythm, or if the ICD senses a faster, dangerous rhythm called ventricular fibrillation, the ICD can then give a shock (defibrillation) to the heart to restore normal rhythm.
Some modern ICDs only provide defibrillation.
These are suitable for patients not in need of cardiac pacing, and are particularly of interest to patients not wishing to bear the risks associated with having leads threaded through the veins to the heart.
Procedure:
This procedure is performed under either a general anaesthetic or a local anaesthetic with sedation. The pulse generator is connected to either one or two leads that, for most models, pass through a vein into the heart. The doctor may test the device during the procedure to ensure it is working correctly. The implant should take between one and two hours and any stitches that may need to be removed will be done at your GP surgery.
You will probably be allowed to go home the next day provided your ICD is checked and there are no complications. You will be given an ICD identity card, emergency information and instructions at this point. You will also be given a helpline number should you have any queries later on.
Normally an ICD battery lasts between six and nine years and the replacement procedure will usually involve changing the ICD generator, not having new leads implanted.
Living with an ICD:
Some patients have reported that having shocks can feel like they have been suddenly kicked or punched in the chest. These shocks can be quite painful but the pain will only last for a few seconds, others may not feel anything.
If you do feel unwell after a shock, or if your device has given you several shocks, please dial 999 for an ambulance. Show the paramedics your identity card along with any emergency instructions; this will inform them of exactly which type of device you have and what the best course of action will be.
You should always contact your ICD centre if you think you have had a shock.
Physical activity with an ICD:
For most patients it is safe to exercise and to take part in sport. Indeed, research has shown that physical activity and exercise are beneficial for people fitted with an ICD.
Individual cases are influenced by the cause and type of your heart rhythm problems and the type of exercise you perform. Your clinicians will be able to advise you of any exercise-related information that is specific to your situation. The likelihood of an arrhythmia is no greater during moderate exercise than during resting but there are certain types of exercise that may increase the risk. If you exercise vigorously from rest, without a warm-up, and immediately cease exercise, with- out a cool down or active recovery period you increase the likelihood of arrhythmia.
Your ICD
Your ICD can detect an abnormal heart rhythm in a number of ways, one of which relates to the speed of the heart during the arrhythmia. Most arrhythmias treated with ICDs will be significantly faster than your normal heart rate would reach, even with strenuous exercise. Occasionally however, the ICD needs to be programmed to recognise abnormal heart rates that are close to those that can be achieved with exercise. For this reason, it is worthwhile to check how your ICD is programmed before anything other than recreational exercise or exercise to lose weight.
If you are concerned about your safe exercise level, you should ask your cardiologist, cardiac physiologist or arrhythmia/ICD nurse specialist.
What about driving?
There may be some restrictions on driving; you can access DVLA guidelines on:
www.gov.uk/driving-medical-conditions
Current rules (2013) place a six month ban on driving following implant of secondary prevention ICD or delivery of an appropriate shock. For primary prevention ICDs the rules are a one month restriction. lt is very important that you discuss this with your nurse, physiologist or doctor at your lCD centre who will explain this in more detail and let you know what is specific to your circumstances.
It is strongly recommended that you inform your insurance company.
For specific and detailed information please see the DVLA website.
A recent alternative to ICDs that require leads attached to the heart is available in some countries. Called subcutaneous ICDs (S-ICD), the new devices are able to defibrillate the heart with only a lead that is placed just beneath the skin instead of into the heart. They are not suitable for all patients.
Reference:
Arrhythmia alliance (UK)