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Implantable Cardioverter Defibrillator (ICD)


An implantable cardioverter defibrillator (ICD) is slightly larger than a pacemaker, and functions much like one.

Unlike a pacemaker, however, ICDs are designed to deliver two levels of electrical impulses: a low-energy shock to return a heart back to normal rhythm, and a high-energy shock if the heart arrhythmia is so severe that the heart is quivering rather than beating.

ICDs are frequently recommended for patients who are at high risk for a potentially fatal ventricular arrhythmia.

ICD components

ICDs have main primary components that help them sense when the heart's rate falls below the rate programmed into the pacemaker:

  • A pulse generator, which produces the signals that make the heart beat.
  • One or more insulated lead wires that carry signals to the heart from the pulse generator. One lead is attached to the pulse generator, while the other lead is placed in one of the chambers of the heart.
  • Electrodes, which are found on each lead.

ICD insertion

ICD insertion is done in the cardiac catheterization lab. Although the patient is awake during the procedure, sedation is usually given to help them relax.

During the procedure, an incision is made just under the collarbone. The lead of the ICD is then inserted into the heart through a blood vessel.

The lead is then tested to ensure that it's functional and in the right place. When the leads are confirmed to be working, they are attached to the generator, which is placed under the skin at the incision site.

You may need a night or two of observation after the procedure to ensure the ICD is functioning as it should.

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