An implantable cardioverter defibrillator (ICD) is a small device that's placed in your chest or abdomen. This device uses electrical pulses or shocks to help control life-threatening, irregular heartbeats (ventricular arrhythmias) especially those that could lead the heart to suddenly stop beating (sudden cardiac arrest). If the heart stops beating, blood stops flowing to the brain and other vital organs. This usually causes death if it's not treated in minutes.
When these ventricular arrhythmias occur, the heart can't effectively pump blood, and a person will pass out within seconds and die within minutes if not treated. To prevent death, the condition must be treated right away with an electric shock to the heart. This treatment is called defibrillation.
An ICD has wires with electrodes on the ends that connect to the chambers of your heart. The ICD will continually monitor your heart rhythm. When the device detects that you're having an irregular rhythm in your ventricles, the ICD will use low-energy electrical pulses to restore a normal rhythm. If this doesn't restore your normal heart rhythm, or if your ventricles start to quiver rather than contract strongly, the ICD will switch to high-energy electrical pulses for defibrillation.
You may need an implantable cardioverter defibrillator (ICD) if you're at risk for certain life-threatening ventricular arrhythmias, such as ventricles that beat too fast or that quiver. For example, you may be considered at high risk for a ventricular arrhythmia if you:
Have had a ventricular arrhythmia before
Have had a heart attack that has damaged the electrical system in your ventricles
An ICD is often recommended for people who have survived sudden cardiac arrest
Other important notes
An ICD is not the same as a pacemaker. A pacemaker can only give off low-energy electrical pulses to correct certain irregular heartbeats. An ICD can give off the high-energy electrical pulses needed to correct dangerous arrhythmias in the lower chambers of the heart (ventricles).
Your doctor may recommend an ICD if he or she sees signs of an irregular ventricular arrhythmia (or heart damage that would make one likely). He or she also may recommend an ICD if you survive sudden cardiac arrest.
Surgery to place an ICD usually takes a few hours. After this minor surgery, you may have mild pain; over-the-counter medicines can usually relieve it. Consult your doctor before taking any pain medicine.
The most common problem with ICDs is that they give pulses too often or when they aren't needed. Doctors can reprogram ICDs or prescribe medicines so the pulses occur less often. There are other rare risks linked to the ICD surgery, such as infection and bleeding.
Once you have an ICD, you have to avoid close or prolonged contact with electrical devices or devices that have strong magnetic fields. You also need to avoid medical procedures that can disrupt your ICD.
Let all of your doctors, dentists, and medical technicians know that you have an ICD.
Your doctor may ask you to avoid any vigorous exercise or heavy lifting for a short period after your surgery. After you have fully recovered from surgery, discuss with your doctor how much and what kinds of physical activity are safe for you.
Have your ICD checked regularly. Some ICD functions can be checked remotely through a telephone call or computer connection to the Internet. Your doctor may ask you to come to his or her office to check your ICD.
ICD batteries have to be replaced every 5 to 7 years. The wires of your ICD also may have to be replaced eventually. You doctor can tell you whether you need to replace your ICD or its wires.