An implantable cardioverter defibrillator (ICD) is a device that monitors heart rhythms, and delivers shocks if dangerous rhythms are detected. Implantable cardioverter-defibrillators (ICDs) can control abnormal, life-threatening heart rhythms and prevent cardiac arrest. ICDs protect against sudden cardiac death from ventricular tachycardia and ventricular fibrillation.

Many ICDs record the heart’s electrical patterns whenever an abnormal heart beat occurs. Doctors can review this record during regular check-ups to help plan future treatment options. Like a pacemaker, an ICD consists of a battery and electrical circuitry (pulse generator) connected to one or more insulated wires. The pulse generator and batteries are sealed together and implanted under the skin, usually near the shoulder. The wires are threaded through blood vessels from the ICD to the heart muscle. The ICD continuously checks the heart rate. When it detects a too-rapid or irregular heartbeat, it delivers a shock that resets the heart to a more normal rate and electrical pattern (cardioversion). Stopping the potentially fatal fibrillation is called defibrillation.


ICDs are used to treat patients whose lower heart chambers (ventricles) beat too quickly (tachycardia) or quiver ineffectively (fibrillation). They are also used in patients who are at risk of these conditions due to previous cardiac arrest, heart failure, or ineffective drug therapy for abnormal heart rhythms.


ICDs are used to treat patients whose lower heart chambers (ventricles) beat too quickly (tachycardia) or quiver ineffectively (fibrillation). They are also used in patients who are at risk of these conditions due to previous cardiac arrest, heart failure, or ineffective drug therapy for abnormal heart rhythms. Potential risks from the surgical procedure include infection, bleeding, and bruising. Other rare complications include stroke, heart attack, blood clots, or perforation of a major vessel, a lung, or the heart muscle. Your doctor will tell you about additional risks from ICDs.

Electromagnetic Interference Some devices in your surroundings may interfere with your ICD. You may need to avoid certain types of security devices. Always carry your wallet ID card with you. Household devices and appliances may affect your ICD. Ask your doctor which devices to avoid. Some medical equipment can damage your ICD. If you are visiting your doctor or dentist, tell him or her that you have an ICD BEFORE they do any testing or treatment. Some security devices may affect your ICD. A general rule of thumb is “Don’t lean, don’t linger” when moving through these devices. Welders and electric generators may affect your ICD.


July 11, 2006. FDA Update Statement on Boston Scientific/Guidant Pacemakers and Defibrillators
FDA met last week with Boston Scientific/Guidant to discuss the firm's recent announcement that several models of pacemakers and implantable defibrillators should be removed from hospital inventories because they have the potential to malfunction due to failure of the capacitor, which controls how the device holds its power supply. FDA fully supports the company's recommendation that physicians perform follow-up exams of patients with devices that may be susceptible to this malfunction. Problems may include intermittent or permanent loss of therapy, premature battery depletion or other malfunctions. FDA is closely monitoring the situation and met with Boston Scientific/Guidant to discuss their plans to investigation the problem, inform physicians and resolve the problem as quickly as possible.

June 23rd, 2006. A U.S. Food and Drug Administration analysis found that Guidant defibrillators may fail as much as 10 times more than the company projected last year. Guidant defibrillators have been implanted into thousands of cardiac patients and are used to restart hearts with electrical pulses. The company recalled 16,000 of its Contak Renewal defibrillators last year but said that no more than 292 of the units were likely to experience problems. The FDA report said that “most” of the recalled defibrillators may have damaged insulation within that time – 40 percent of which would fail to produce a life-saving shock in a medical emergency.

On July 7th, 2006. MRL, Inc., Welch Allyn Company initiated a voluntary worldwide recall of 1,184 PIC50 External Monitor/Defibrillators manufactured in Buffalo Grove, IL between February 2002 and October of 2004. These PIC50s may display a DEFIB COMM ERROR, which may prevent or unacceptably delay the delivery of therapy, which may fail to resuscitate the patient. This problem occurs because of an intermittent electrical connection within the device. This recall is being conducted with the full knowledge of the U.S. Food and Drug Administration (FDA). FDA has determined that this action is a Class I recall. The FDA defines Class I as a situation in which there is reasonable probability that the use of or exposure to the product will cause serious adverse health consequences or death.

June 2005, St Jude Medical Incorporated announced that some of its implantable St Jude defibrillator models have a software problem that could cause the heart-shocking device to malfunction. In addition, some of the defibrillators may contain background levels of atmospheric ionizing cosmic radiation, more commonly known as cosmic rays.

February 11, 2005. Medtronic Inc. issued a statement to physicians advising them that over 80,000 implantable cardioverter-defibrillators (ICDs) and cardiac resynchronization therapy defibrillators (CRT-Ds) are prone to battery depletion and failure. The battery shorting mechanism could cause the battery in these defibrillators to experience a rapid depletion of power resulting in the loss of device function.

The FDA is interested in receiving information about problems with any devices and encourages hospitals and the public to submit reports directly to MedWatch, the FDA's voluntary reporting program. Reports may also be submitted by phone at 1-800-FDA-1088; by fax at 1-800-FDA-0178; by mail to MedWatch, Food and Drug Administration, 5600 Fishers Lane, Rockville, MD 20857-9787; or online at http://www.fda.gov/medwatch/report.htm.