Defibrillator (ICD/AICD)

Also called as ICD (Implantable cardioverter defibrillator)

Some heart abnormalities can cause your heart to beat too quickly, too slowly or in an irregular pattern. These heart rhythms can happen suddenly and unexpectedly and sometimes people die as a result of this.

A defibrillator (ICD) can give your heart electric pulses or shocks to get your heart rhythm back to normal. The ICD is inserted under your collar bone. It looks similar to a pacemaker and is a little bigger than it. It consists of two parts

  • A pulse generator- a battery powered electronic circuit
  • One or more electrode leads which are placed into your heart through a vein

Mostly, ICDs are implanted under local anaesthesia and the procedure can take an average of one to one and half hours.

defibrillator

Also called as ICD (Implantable cardioverter defibrillator)

Some heart abnormalities can cause your heart to beat too quickly, too slowly or in an irregular pattern. These heart rhythms can happen suddenly and unexpectedly and sometimes people die as a result of this.

A defibrillator (ICD) can give your heart electric pulses or shocks to get your heart rhythm back to normal. The ICD is inserted under your collar bone. It looks similar to a pacemaker and is a little bigger than it. It consists of two parts

  • A pulse generator- a battery powered electronic circuit
  • One or more electrode leads which are placed into your heart through a vein

Why do I need an ICD?

ICDs are used for some people in the following groups:

  • people who have had ventricular tachycardia (VT) are at risk of having VT again
  • people who have previously had a cardiac arrest due to VT or VF (ventricular fibrillation), and are at risk of having VT or VF again
  • people who may be at high risk of developing VT or VF due to another heart condition, and
  • people who have taken medicines or had catheter ablation for ventricular arrhythmias, but who need extra protection against the risk of getting these arrhythmias again.

How is ICD implanted:

It can take anything from one hour to two hours to implant an ICD. The length of time needed depends on the type of device you are having. Sometimes the implant is done as a day case, which means that you don’t have to stay overnight in hospital. Other people may need to stay in hospital either overnight, or in some cases for a few days. Most people will have a local anaesthetic as well as sedation, but few will have a full (general) anaesthetic. Your cardiologist will discuss this with you before you have the procedure.

Most ICD leads are inserted into the heart through a vein. (This is called ‘transvenous implantation’.) The pulse generator is most commonly implanted on the left side of the body, in the upper chest near the shoulder, under the skin.

Going back to the ward, and recovering from the procedure

When you get back to the ward, you will be attached to a heart monitor for a few hours. The nursing staff will do regular checks when you first get back to the ward. For example, they will regularly take your blood pressure. They will also assess whether there is any bleeding from the incision site (where the cut was made).

Once you are fully awake, you can have something to eat and drink. Check with your nurse when you can get out of bed. Most people are walking around later the same day and are ready to leave hospital later that day or the day after.

You may feel some discomfort, and there can be quite a lot of bruising at the place where the ICD was inserted, but these problems usually disappear soon afterwards. A doctor should prescribe painkillers for you to take if you need them while you are in hospital or at home. You will need to be careful not to put too much pressure on the arm nearest the ICD (usually the left arm), or to lift that arm up too far.

This is to try to help prevent the ICD leads moving before they settle into the heart’s tissue. The staff in the hospital will advise you on the best way to sit up, and on how far you can move your arm – usually no higher than shoulder height.

The incision (cut) will be about 4 to 7 centimetres long. You will have a dressing over the wound. You may also have extra padding over it, to provide pressure to help stop any bleeding. It is important to keep the wound dry for the first few days while it heals, so try to make sure the dressing or padding doesn’t get wet.

Before you leave hospital

You may have a chest X-ray before you go home, to check that the leads have not moved out of position.

Testing the ICD

Before you leave hospital,a cardiac physiologist will do some tests to check the ICD. The settings will also be checked. If necessary, the physiologist will program (adjust) the ICD using a special computer.

Information about your ICD

 Before you leave hospital, you should be given some information on living with an ICD, including information on driving, and any activities you should avoid doing.

A cardiac physiologist will also explain any special features of your ICD. For example, some ICDs can be programmed to make a special sound or vibrate when they are about to deliver a shock, or when the battery is getting low, or if there are problems with the electrode leads. These features vary from one device to another.

 How does Defibrillator (ICD) works?

Your ICD constantly monitors your heart rhythm through the electrodes. If it notices a dangerous heart rhythm it can deliver the following treatments:

  • Pacing- a series of low voltage electrical impulses (paced beats) at a fast rate to try and correct the heart rhythm
  • Cardioversion- one or more small electric shocks to try and restore the heart to a normal rhythm
  • Defibrillation- one or more larger electric shocks to try and restore the heart to a normal rhythm

Living with an ICD

Physical activity with an ICD

Building physical activity into your everyday routine will help with your recovery and help to keep you and your heart healthy.

After you have had your ICD fitted, you will be advised not to do any strenuous activity for about six weeks. For the first few weeks, don’t lift the arm, which is on the same side as your ICD above shoulder height, or carry anything too heavy with the arm on the side of the ICD. This is because there is a very small risk that one of the leads of the device might move out of position. However, during these first weeks it is very important to keep your shoulder mobile by gently moving the arm on the side of the ICD. You may need pain relief to help with this, especially in the first few days. You can usually start most of your normal activities again within a few weeks of having the ICD fitted. Gradually build up your activity. Start slowly at a level that suits you and gradually build up the amount of time you spend doing the activity and how intensely you do it. If you are concerned about how much and what type of activity you can do, the staff at the ICD clinic, or the health professionals looking after you, can advise you about what is a safe exercise level for you.

Moderate-intensity physical activity is safe for most people who have an ICD. Moderate-intensity activity means activity that makes you feel warmer and breathe harder, and makes your heart beat faster than usual, but you should still be able to carry on a conversation. It is important that you warm up before doing your activity and cool down afterwards. Begin your activity slowly for the first few minutes and build up gradually. When you come to the end of your activity, take time to slow down and cool down for a few minutes, and make sure you don’t stop suddenly. Stop exercising if you feel pain, dizzy, sick or unwell.

Avoid doing activities that could be dangerous for you if your ICD were to deliver its defibrillation treatment – for example, scuba diving, or swimming on your own.

Interference with Electrical equipment

An ICD has a metal case to protect it from damage and outside interference. It also has special circuits to detect and remove unwanted electrical activity and prevent interference.

At home

Electrical equipment that you use at home – such as shavers, hairdryers and microwave ovens – will not be a problem, as long as it is well maintained.

Phones and computer equipment

Mobile phones and cordless phones

You can safely use your mobile phone or a cordless phone, but it is best to keep the phone more than 15 centimetres (about 6 inches) from your ICD. Try to use the ear on the opposite side to your ICD, and don’t put either type of phone in a shirt pocket over your chest. You don’t need to worry if someone else is using a mobile or cordless phone in the same room as you.

Hands-free kits and bluetooth

There has been no clear evidence of these devices affecting ICDs, but some manufacturers suggest that you use the ear on the opposite side to your ICD.

MP3 players, palm PCs and pocket PCs

You can use iPods and other brands of disk-based or solid-state MP3 players and palm or pocket PCs, as long as you don’t place them directly over the ICD. Keeping at least 15 centimetres (6 inches) between the device and your ICD avoids any risk of interference. Avoid putting the headphones within 3 centimetres (just over 1 inch) of your ICD. And don’t put them in a pocket near the ICD or let them dangle around your neck, even when you are not using them.

WiFi,wireless LAN and wireless internet for computers

There is no clear evidence to say that these interfere with ICDs.

Airport security systems

Airport screening systems very rarely cause problems with ICDs. If you have an ICD, you should carry your ICD identification card with you when you travel by plane. The security metal detector can detect an ICD, so you need to tell the security staff that you have an ICD inserted. You should either have a hand search by one of the security staff, or be checked with a hand-held metal detector. The metal detector should not be placed directly over your ICD.

Security systems in shops

Many shops have anti-theft detection systems in their doorways. If you walk steadily through and don’t linger, there should be no effect on your ICD. It’s best not to stand too close to this type of security system for long. Keep about one metre (three feet) away from it.

Metal detectors

Metal detectors may affect ICDs, so you should speak to your ICD clinic before using one.

Magnetic devices

Small magnetic devices, such as magnetic fasteners on items of clothing (usually on jackets) could affect your ICD. Clothes with magnetic fasteners usually carry a warning label. You should avoid wearing magnetic fasteners near your ICD.

Medical and dental tests and treatments

Most medical and dental tests will not affect the ICD, but some equipment may cause some interference, so always make sure that you tell whoever is treating you that you have an ICD. MRI scans are hardly ever used for people who have an ICD, due to the MRI’s strong magnetic field. So you must not have this test unless it has been discussed carefully both with you and with the staff at your ICD clinic.

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