Defibrillator Implantation and Programming

Implantable Cardioverter Defibrillators (ICDs)

What is an ICD?

An ICD is otherwise known as an implantable cardioverter defibrillator. The defibrillators primary function is to watch every heartbeat, and if the heart rate becomes abnormally fast in the ventricles it will deliver either a pacing stimulus our a shock down a wired that is implanted in the heart which will stop of disrupt the rhythm.

The device can be programmed to either speed up or slow down the heart rhythm because all ICDs also have a pacemaker in them. The pacemaker is primarily a back up, which may be necessary after a shock is delivered to keep the heart from going to slow. The pacemaker within the ICD, may also function to help your heart go faster as needed with day to day activities.

The major components of the ICD generator are the capacitor, which holds the energy to deliver therapy to the heart, the battery, and the microprocessor. Within the generator the microprocessor stores diagnostic data that can be relevant to your care and treatment. The ICDs has two components: the generator itself, which is the size of a thick business card, and the electrodes, or wires that will extend into the heart. The wires have the ability to both watch the hearts activity, as well as deliver therapy as needed.

Why is the doctor performing this procedure?

An ICD is implanted to monitor an abnormally beating heart, either one that beats too fast (tachycardia), too slow (bradycardia) or irregularly (atrial fibrillation). These abnormal heart beats are referred to as arrhythmias.

When is an ICD indicated?

Your doctor has recommended you for an ICD system for one or more of the following reasons:

  • At least one episode of Ventricular Tachycardia (VT) or Ventricular Fibrillation (V-fib)
  • Previous cardiac arrest or abnormal heart rhythm that has caused you to pass out
  • A fast heart rhythm that keeps returning and could cause death
  • A fast heart rhythm that cannot be cured by surgery
  • A fast heart rhythm that cannot be controlled with medications
  • Severe side effects from medications

What happens during implantation of an ICD?

Prior to implantation of an ICD, an electrophysiological study (EP study) may be performed. An EP study is used to help decide whether to use an ICD or whether to use drugs for treatment.

The newer ICD units can be implanted without major surgery and the procedure is performed using local anesthesia. You will be hooked up to an intravenous (IV) line and will receive sedation. Before the doctor makes an incision, your upper chest will be cleaned and your torso draped. Your arms may be loosely strapped to prevent movement during the testing of the ICD.

The doctor will make an incision in your upper chest area below the collarbone. A wire will be inserted through a vein into your heart. Sometimes more than one wire is used. The doctor will create a "pocket" in your chest, where the ICD is inserted. The ICD is connected to the wires. The doctor will test the ICD by creating an arrhythmia and then observing whether the ICD delivers the required therapy.

Recovery time after implantation of newer ICD units is quite short. Patients generally spend one night in the hospital and will go home the next day if there are no complications. People with ICDs must continue to follow their doctor's recommendations regarding medication, diet, and exercise.

Prior to discharge, you will be shown how to examine your incision site. You should look for signs of infection each day such as increased redness, increased tenderness, swelling around the incision, drainage from the incision. You should also report a fever over 100°F that lasts longer than 24 hours. You will also receive instructions on your ICD.

What are possible complications?

Any surgical procedure includes the possibility of complications. The most typical complications for ICD implantation are not life threatening, but may require a longer hospital stay or a repeated operation. The most common complications include bleeding, infection, lead dislodgement, and problems with the ICD working properly. Ask your doctor about potential complications before your surgery.

The defibrillator unit can cause local discomfort. The most common long-term complication is the delivery of shocks when the patient does not need them. This is less of a problem with more recent devices. The patient is usually quite aware of each shock, even though it is very short in duration. The patient's doctor should be notified of every shock the patient feels. When the batteries have depleted their energy, the pulse generator must be replaced. Replacement of the pulse generator requires minor surgery. Cost should also be considered a factor.

What should I do if I receive a shock?

If you have symptoms of a fast heart rate, it is likely that your ICD will deliver a shock within a few seconds. There is not usually much time to react. Some patients describe the shock as a feeling like a quick click or hiccup; others feel a thump and have described it like a blow to the chest. Whatever you feel, you should adhere to the following guidelines:

  • Remain calm and find a place to sit or lie down.
  • If possible, have someone who is prepared to provide you with CPR stay with you throughout the event, should you need it.
  • Have a friend or family member call 9-1-1 if you remain unconscious for more than one minute.
  • If you are conscious but do not feel well after the shock, have someone call your doctor. Follow your doctor's orders carefully.