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Automated implantable cardiovertor defibrillator (ICD)

Prof Nicholas Peters is a leading London specialist in ICD procedures


An ICD is a device implanted under the skin and connected to wires, or leads, that are placed in the heart.

It continuously monitors the heart to detect changes in its natural rhythm. An ICD detects a too-rapid or chaotic heartbeat and delivers a strong electrical shock to restore the heart to its natural beat. ICDs also act as pacemakers.

A defibrillator (ICD) is larger than a pacemaker but still goes under the skin.

Do I need an ICD?

The Heart Rhythm Society have developed guidelines to help physicians and patients decide whether an ICD is the best treatment for an individual at risk for sudden cardiac death. It is agreed that ICD therapy is of benefit for:

Secondary Prevention: This includes individuals who have suffered a prior cardiac arrest or who experience spontaneous, sustained episodes of dangerous rapid heart beating that is not self-correcting.

Primary Prevention: This is treatment for patients who have never experienced the deadly heart rhythm disorders that lead to sudden cardiac death, but have significant risk factors for the conditions, including patients with poor heart pump function (ejection fraction).

What is involved and what are the risks?

You will be advised not eat or drink 6 hours before your procedure. Please say if you are right or left handed so the cardiologist can chose which side to place the device. Normally ICD implant patients receive local anaesthetic and are sedated for their procedure. Once the working area is sterile the doctor will administer a local anaesthetic to numb the area just underneath the collarbone.  A small cut (incision) a few inches long just below your collarbone will be made. One, two or three wires called ICD leads will be advanced into your heart chambers through the veins in this area, using X-ray guidance, and stitched into position. The ICD generator box will be slipped in under your skin or muscle and attached to the leads. A cardiac physiologist will test the pacing leads using a special ICD lead analyser to ensure best lead placement. The ICD generator will also have to be tested. To do this you will be sedated. Following this the wound is closed using stitches, cleaned and dressed. After your recovery, you will be transferred to the cardiac ward where you will stay overnight.

Before leaving hospital you be will sent for an X-ray to confirm the position of the ICD leads. You will also have a pre-discharge ICD follow-up and will be prescribed a week’s course of antibiotics, which you must complete.

The ICD now would last at least 5-7 years, depending on how well it is programmed and used, often much longer. We can tell when the pacemaker battery begins to run low, when we interrogate the device with the computer on a 6-monthly or annual basis.

ICD implantation is a routine procedure and complications are rare. However, like any surgical procedure, there is a small degree of risk.  Some of risks associated with ICD implantation are: puncturing the lung or heart tissue, infection and bleeding around the wound site or ICD leads. However, the benefits of having an ICD far outweigh the minimal risks. The primary benefit for having ICD implanted is prevention of sudden cardiac death as a result of rhythm disturbances.


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