|What Is An Implantable Cardioverter Defibrillator?
An implantable cardioverter defibrillator (ICD) is a medical device that is surgically placed inside a person's chest or abdomen. It emits small electrical pulses to speed up a heart beat that has slowed down. Or it can emit a stronger electrical shock to re-start a heart that has stopped beating (this treatment is called defibrillation). If the heart has stopped, without defibrillation the patient is likely to die within minutes. People with life-threatening arrhythmias (irregular heartbeats) and those at risk of sudden cardiac arrest (SCA, also called sudden cardiac death) are candidates for this device. An ICD is not a cure for heart disease; it simply minimizes the risk of dying from SCA.
How Does It Work?
The heart has its own internal electrical system that controls how often it beats (your heartbeat). A problem with this electrical system can cause an arrhythmia. Most arrhythmias are harmless and may just involve the occasional skipped heart beat or a slightly slower or faster heart beat than normal. But some arrhythmias can be highly dangerous - in particular those that occur in the lower chambers (ventricles) of the heart. One example is called ventricular fibrillation (VF). VF occurs when disorganized electrical signals cause the heart muscle to twitch rather than pump. After a few minutes, pumping action fails completely and the person passes out and dies (SCA). AF is the most common cause of SCA. If the victim does not have an ICD implanted their only hope of survival is to be treated with an electric shock to the heart with an automated external defibrillator. If they had an ICD implanted, the device would detect the lack of a regular heart beat and send low energy impulses to the heart chamber to kick-start it. If that didn't work, it would automatically switch to a high energy pulse to shock it into normal contractions. These high energy impulses only last a second but they can be quite painful.
What Is The Difference Between An ICD And A Pacemaker?
An ICD is slightly larger than a pacemaker although both are implanted under the skin of the chest. A pacemaker is designed for those with less dangerous types of arrhythmias, such as those that happen in the upper chamber of the heart (like atrial fibrillation). Pacemakers only give off low-energy impulses. All new ICD's have inbuilt pacemakers. This means ICDs can act as a pacemaker by monitoring and correcting minor irregular heart rhythms, but also act as a defibrillator by treating serious irregular heart beats with an electric shock. ICDs are usually prescribed to patients with severe heart damage after a heart attack or those at risk of the most dangerous types of arrhythmia that cause SCA.
Who Needs An ICD?
Your doctor may recommend an ICD if you are at risk of certain types of arrhythmia. This includes:
• Ventricular fibrillation.
• Ventricular tachycardia.
Or you may be prescribed an ICD if you:
• Had a heart attack which damaged your electrical system.
• Survived SCA.
• Have a heart condition that weakens or interferes with your heart pumping action. This includes those with congenital heart disease, Brugada syndrome and younger people with a rare hereditary disorder called long QT syndrome. At the very least these patients should consider having a home defibrillator in case of emergencies.
Arrhythmia diagnosis: How irregular heartbeats are diagnosed.
Electrocardiogram (EKG) and echocardiography: Diagnostic tests.
Event monitor and Holter monitors: Portable monitors that record the heart's electrical activities over a period of time.
Implantable Cardioverter Defibrillator Surgery
X-ray showing installed ICD device
You receive a light sedative medication so that you are awake, but relaxed during the procedure. Typically, an ICD is implanted as follows:
1. Empty your bladder before the procedure.
2. You will be given a hospital gown to wear and told to remove all jewelry.
3. An IV drip will be inserted into your arm before the procedure so that you can be given medications.
4. You will be placed on your back on the operation table.
5. Sticky electrode pads are attached to your chest so that your vital signs (heart rate, breathing rate, oxygen levels and blood pressure) can be monitored by an EKG.
6. A sedative is put into the IV drip to help you relax.
7. The incision site is cleaned with an antiseptic and sterile sheets are placed around the area.
8. A local anesthetic is injected into the skin at the site of insertion.
9. An incision is made.
10. A plastic tube (called an introducer or sheath) is inserted into a blood vessel (usually) under the collarbone. The wire of the ICD will be fed through this tube and advanced into the heart. You need to remain very still to prevent damage while this is being done.
11. Once the wire is fed into the heart it will be tested to make sure it works properly. There may be 1, 2 or 3 wires, depending on the type of ICD unit you are receiving.
12. Once the wire(s) are in place another incision is made and the ICD device will be slipped under the skin and the wire(s) is attached to it. Generally the ICD will be placed on your non-dominant side. So if you are right handed it will be placed in the upper left chest.
13. The ICD is tested to make sure it works properly. The skin is closed with a special glue or sutures or adhesive strips. A bandage is placed over the wound.
The entire surgery takes a few hours and you should expect to stay in hospital for 1 to 2 days.
• You will be taken to the recovery room where a nurse will monitor your vital signs for a specific period of time.
• You should arrange for someone to drive you home because you are not allowed to drive for at least a week after surgery. If you have had SCA or suffered fainting spells from ventricular arrhythmia, your doctor may advise you not to drive until you have gone 6 months without fainting.
• You will need to avoid high-impact activities and heavy lifting for about a month.
• You will be given specific instructions on what to do if the ICD administers an electric shock (for example, calling 911 or going to the nearest emergency room).
What Are The Risks Of Having An ICD?
Related To Surgery
Although rare, the following risks are associated with surgery:
• Infection at the site of insertion. Or swelling and bruising.
• Nerve, blood vessel or heart damage.
• Collapsed lung.
• Adverse reaction to the anesthetic.
Receiving unnecessary electrical pulses: Sometimes ICDs can give electrical impulses or shocks that are not necessary. This may be due to equipment damage or due to a fast heart rate caused by physical activity. It can also happen if you forget to take your antiarrhythmics (arrhythmia medications). Pulses sent when they are not needed can cause irregular heartbeats, which can be painful and upsetting (if not dangerous). If this happens, your surgeon will reprogram your ICD device.
Heart failure: Some research suggests a link between congestive heart failure and ICDs. It is not however clear if ICDs cause heart failure or if heart failure is simply more common in those who need ICDs.
Implantable Cardioverter Defibrillator Precautions
Your doctor will advise you on the best care for your particular ICD device. In general, the following precautions should be taken:
Identification: Always carry an ID card and wear an identification bracelet that states you have an ICD. In the event of an emergency this will prevent medical staff inadvertently giving you treatment which could damage your device.
Electrical equipment: Avoid prolonged contact with electrical devices that have strong magnetic fields. These include:
• Cell phones and music players (including iPods and MP3 players).
• Microwave, home appliance. You can still use it, but stand away from it while it is heating food.
• Magnetic resonance imaging (MRI) scans.
• Radar or high volt equipment such as TV transmitters, radars, electrical generators and high-tension wires.
• Turn large motors like boats and car engines off when not working on them. They could confuse your device.
Security (Metal) detectors at airports:
While you can walk through detectors at a normal pace, someone holding a handheld device should not hold it too long over the site of your ICD. Also, avoid standing too long near a metal detector. Notify security staff if you have an ICD, they are usually very obliging.
How Long Does It Last?
The batteries in your device typically last between 5 and 7 years. Your surgeon will replace the bulky part of the device (called the generator) before the battery starts to run down. Eventually the wires will also need to be replaced. Replacement surgery is quicker than the original surgery. Your doctor will tell you if you need to have just the ICD replaced or both the ICD and the wires.
When is CPR necessary?
How is hands only CPR performed?
How Much Does An ICD Cost?
The initial ICD implantation costs range from $28,500 to $55,200*, with an annual follow-up cost from $4,800 to $17,000. Most insurance companies will cover these fees.
*Systematic Review of ICD Costs and Outcomes (2006, Peter W. Groeneveld, MD, MS).