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School of Medicine
Implantable Cardioverter-Defibrillators (ICDs)
Implantable Cardioverter Defibrillators are commonly used to treat patients who have experienced a potentially dangerous ventricular arrhythmia. These devices continuously monitor the heartbeat and automatically deliver a small electrical shock to the heart if a sustained rapid heart rhythm occurs.
The shock may cause momentary discomfort, which is described by some patients as being “kicked in the chest.” ICDs also function as pacemakers and can be used to treat both slow and fast heart rhythm abnormalities. ICDs must be checked every three to four months and replaced every four to eight years.
Implantable Cardioverter Defibrillators
The ICD is composed of a titanium encased pulse generator (the size of a small box of raisins) that contains a lithium battery and electrical circuitry and capacitors attached to one, two, or three leads (wires) that are inserted in to the heart. It monitors heartbeats and, when appropriate, generates a small electrical impulse to pace the heart or a large electrical impulse to shock the heart.
How is the ICD implanted?
The technique used to insert an ICD is almost identical to implanting a pacemaker. It is performed in the EP lab and takes two to three hours.
- A two-inch incision is made beneath the collarbone and a small “pocket” under the skin is created for the pulse generator.
- The leads are inserted into the heart through a large vein that runs under the collarbone.
- Once the leads are positioned in the heart, they are attached to the pulse generator. Then the patient’s abnormal heart rhythm is deliberately triggered to determine how much energy is required to shock the heart back into normal rhythm. This allows the ICD to be optimally adjusted.
- During the procedure, the nurse will give you pain medication and a sedative to be certain you are comfortable. When the ICD is tested, patients are fully asleep.
- You will receive detailed follow-up instructions before you leave the hospital. It is important that you follow these instructions and call your doctor or nurse with any questions.
You will also need to carry an ID card with you, which can inform medical personnel of important manufacturer specific details regarding your device. You may also need to show your ID card to security personnel because the device may set off security devices in airports and other high-security areas.
The risks associated with placement of an ICD are low and will be discussed in detail with you before the procedure.