Your doctor may have told you that you need an implantable cardioverter defibrillator (ICD.) An ICD is a small, lightweight electronic device that is placed inside your body that keeps track of your heart rhythm. When you have an arrhythmia, the ICD helps your heart return to normal rhythm. The ICD is not a cure for your heart rhythm problem. However, it can save your life by quickly bringing a dangerously fast heart rhythm (which could lead to cardiac arrest) under control. If the determination is made that you will have an ICD implanted, you will need the device for the rest of your life, so having one implanted means a lifelong commitment.

Two types of fast heart rhythms, ventricular tachycardia (VT) and ventricular fibrillation (VF), can lead to cardiac arrest, so an ICD usually is needed.

• Ventricular Tachycardia (VT)
  With VT, a ventricle (lower heart chamber) contains a group of abnormal electrical cells called a circuit. The circuit sometimes sends out signals that make the lower chambers beat very fast. The chambers don’t have time to fill with blood before the next beat. So, the heart pumps less blood than the body needs, causing your symptoms. VT can progress to a more serious arrhythmia, ventricular fibrillation.
  
  
• Ventricular Fibrillation (VF)
  With VF, abnormal circuits in the ventricles sometimes send signals quickly and irregularly. The heartbeat can be so fast and uneven that the heart muscle quivers rather than pumps. A quivering heart is in cardiac arrest. Emergency treatment must be given to get the heart pumping again, or death may result.

Causes of VT and VF
VT and VF usually develop in damaged heart muscle. This damage may be caused by:

• A scar on the heart muscle from a heart attack.
• Cardiomyopathy, which is a diseased, weakened heart muscle.
• Other problems, including heart valve problems and congenital (present at birth) heart problems.

Sometimes, a heart rhythm problem can exist even though the heart muscle hasn’t been damaged. This is called a primary electrical problem.

What an ICD Does To Fix An Arrhythmia
An ICD can do one or more of the following:

• Antitachycardia pacing (ATP): The ICD can send out a series of pulses to override a fast rhythm. This may feel like fluttering in your chest, or you may not feel it at all.
  
  
• Cardioversion: If ATP doesn’t slow a fast rhythm, the ICD can give the heart one or more small shocks. These break up the fast rhythm. They may feel like thumps in your chest.
  
  
• Defibrillation: If the ICD senses a very fast, irregular rhythm, it quickly sends a strong shock to the heart to override the fast rhythm. This may feel as strong as a kick to your chest.
  
  
• Bradycardia pacing: An ICD’s main job is to slow a fast heart rhythm. Sometimes, however, your heart might beat too slowly as well. This may happen if you have a second heart rhythm problem that causes a slow heartbeat. Most ICDs can also send out pulses to get a slow heartbeat back to the right speed.

• You will be asked not to eat or drink anything after midnight prior to your procedure.
   
  
• Unless you are already hospitalized, you probably will be admitted on the day of the procedure, or the night before.
  
  
• Several routine lab tests will be done, including an ECG and blood tests. (Blood tests may be done one or two days ahead of the procedure.)
  
  
• When you arrive at Abbott Northwestern Hospital, you should report to the Day Angiogram admitting desk in the Piper Building lobby (on the northeast corner of the campus, on the corner of 26th Street and 10th Avenue; Choose from the following links to view maps and directions or a campus guide.) You will then be taken to the Cardiovascular Outpatient Care Unit to prepare for the procedure.
  
  
• The doctor performing the implantation will review your medical history and examine you. (Your EP doctor may see you several days before the procedure.)
  
  
• The doctor will explain the procedure, its purpose, potential benefits, and possible risks. This is a good time to ask questions and, most importantly, to share any feelings or concerns you may have. You’ll then be asked to sign a consent form.
  
  
• During the procedure, you will receive fluids and medication (to help you relax) through an intravenous (IV) line. You will not be anesthetized (“put to sleep”) during the procedure.

• Implanting an ICD is a minor surgical procedure that may be performed in the electrophysiology (EP) lab under local anesthesia. (In some cases, the ICD is implanted through open-chest surgery, usually along with surgery for another heart problem, such as a coronary bypass. In these cases, general anesthesia is used.)
  
  
• Most often, the ICD is implanted in the upper chest, near the right or left shoulder. (Occasionally, it may be implanted in the abdominal area.)
  
  
• A local anesthetic is injected to numb the area where the ICD will be inserted. An incision is made below the collarbone and a “pocket” is created under the skin, for the pulse generator to sit in.
   
  
• The lead is inserted into a vein through the chest incision. With the help of a x-ray camera, the lead is passed through the vein and is positioned inside the heart. If a second lead is needed (dual chamber ICD), this process is repeated. Sometimes an additional lead is needed for resynchronization of the lower heart chambers. For more information on resynchronization pacemakers, visit Pacemaker Implantation.
  
  
• After the lead is in position, it is tested to make sure it senses the heart signals clearly. Each of the leads is then connected to the pulse generator.
  
  
• The pulse generator is set to treat your heart rhythm problem and is placed in the pocket in your chest. The device is then tested, to make sure it is working properly. The incision is closed and covered with a sterile dressing.
  
  
• The implantation usually takes one to two hours (longer if a resynchronization lead is required.) Be sure to let the staff know if you feel any pain or discomfort at any point during the procedure.

• After the ICD is implanted, you’ll be transported to the recovery area or to your room.
  
  
• A nurse will take your pulse and blood pressure and will also check the incision for bleeding or swelling.
  
  
• You will be on bedrest for four to six hours and you will stay overnight in the hospital.
  
  
• The morning after your procedure your doctor and a pacemaker clinic team member will see you to check your ICD and review discharge instructions.
  
  
• When it’s time to leave, have a friend or family member drive you home – you may resume driving in 24-48 hours.

• Home Care Following Pacemaker or ICD Implantation

Other procedures for this sub-specialty

• Cardioversion 
• Electrophysiology Study and Catheter Ablation 
• Pacemaker & ICD Follow-up/Evaluation 
• Pacemaker Implantation 
• Stereotaxis 
• Tilt Table Testing