Pacemaker/Implantable Cardioverter Defibrillator Insertion

Overview

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What is a Pacemaker/Implantable Cardioverter Defibrillator (ICD)?

A pacemaker is a small electronic device composed of three parts: a generator, one or more leads, and an electrode on each lead.

The generator is the "brain" of the device. It is a small metal case that contains electronic circuitry and a battery. The lead (or leads) is an insulated wire that is connected to the generator on one end, with the other end placed inside one of the heart's chambers. The electrode on the end of the lead touches the heart wall and senses the heart's electrical activity. This information is relayed to the generator by the lead. If the heart's rate is slower than the low limit programmed into the generator, an electrical impulse is sent through the lead to the electrode and the pacemaker's electrical impulse causes the heart to beat at a faster rate. When the heart is beating at a rate faster than the programmed low limit, the pacemaker will monitor the heart rate. No electrical impulses will be sent to the heart unless the heart's natural rate falls below the pacemaker's low limit.

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An internal cardioverter defibrillator (ICD) looks very similar to a pacemaker: it has a generator, one or more leads, and an electrode for each lead. These components work very much like a pacemaker. However, the ICD is designed to deliver an electrical shock to the heart when the heart rate becomes dangerously fast. New ICDs can also serve as a pacemaker.

The procedure for inserting either a pacemaker or an ICD is basically the same. You are taken to the electrophysiology (EP) lab or the cardiac catheterization lab for the procedure. You will be awake during the procedure, but you will be given a sedative medication to help you relax. An intravenous (IV) line will be placed in your hand or arm. You will be attached to an EKG monitor. The physician will insert the pacemaker or ICD lead wires into your heart through a vein, usually through the subclavian vein (a large vein just under your collarbone). Once the lead wires are in place, they are tested to make sure they work and are in the correct spot. A small incision will be made just under your collarbone, and the pacemaker or ICD generator (a very small, thin, metal box just slightly larger than a book of matches; it contains a battery and circuitry) will be attached to the lead wires, then inserted into the small pocket made for it under the collarbone. The incision is closed, and the procedure is finished.

Reasons for the Procedure

A pacemaker is inserted in order to provide stimulation for a faster heart rate when the heart is beating too slow, and other treatment methods, such as medication, have not improved the heart rate. An ICD is inserted in order to provide cardioversion or defibrillation when the heart beats too fast.

Risks of the Procedure

Possible risks of pacemaker or ICD insertion include, but are not limited to, the following:

• perforation of the heart muscle
  
  
• heart attack from inducement of a very fast rhythm, or from a clot being dislodged by the catheter
  
  
• stroke (brain attack) from a clot being dislodged by the catheter
  
  
• bleeding from the catheter insertion site
  
  
• damage to the vessel at the catheter insertion site
  
  
• infection of the catheter site

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