While many people might be most familiar with the external defibrillators seen on TV, in emergency rooms or at sporting events, there are similar devices that, although less obvious in their use, serve the same purpose of restoring proper heart rhythms and thus averting possible death by cardiac arrest or heart attack. They are called implantable cardioverter defibrillators but are often referred to as pacemakers. An implantable cardioverter defibrillator is a device designed for individuals with certain forms of heart disease of defects that put them at recurring risk of sustained ventricular fibrillation, or cardiac arrest. The device is implanted either within the chest itself, or more commonly today within the blood vessels thus eliminating the need for dangerous open chest surgery. Once inside the body, an implantable defibrillator, or ICD, uses leads positioned near the heart to deliver electronic pulses or shocks when the device senses a cardiac rhythm that is out of sync. This arrhythmia or fibrillation can lead to cardiac arrest by constricting blood flow to the heart. The device can also, if necessary, stimulate a consistent pace or beat if the heart is unable to do so on its own. Internal defibrillators are only used in cases where a patient has shown consistent, recurring risk of cardiac arrest or attack do to fibrillation. As with any invasive surgery, an ICD is not to be taken lightly, but they have been extraordinarily useful in preventing sudden deaths among patients who elect to have them implanted. If you are wondering if you are a candidate for an ICD, contact your regular medical practitioner or heart specialist. Only they can determine whether you are in need of an internal defibrillator, but if you have been found to be at recurring risk for rhythm problems such as ventricular tachycardia (when the heart beats at a dangerously fast pace) or ventricular fibrillation (when the heartbeat is both fast and irregular), an ICD may be a viable option. Patients who have ICDs implanted often say that the delivery of pacing therapy by the device is a painless experience. Most do not experience discomfort or pain, while some may feel a mild fluttering in the chest. If cardioversion therapy is needed, a mild shock is sent that is said to resemble a thump in the chest. The defibrillator shock, sent to resolve cardiac fibrillation or irregular pacing, is the heaviest jolt and is often said to resemble a swift kick in the chest. There may be some discomfort but the sensation typically only lasts a few moments. Once you have an internal defibrillator implanted, certain lifestyle adjustments will be necessary. Like after any surgery, your doctor will advise you to limit any strenuous or stressful activities for a certain period of time. But in most cases, you can return to a normal routine after a few short weeks. Though, patients will need to be aware of any machines capable of interfering with the ICD’s operation. Devices with strong magnetic fields are of particular concern. Though doctors will always be hopeful to avoid major invasive surgery such as the implantation of an ICD, implantable cardioverter defibrillators have allowed thousands of heart patients to live out long and productive lives despite a recurring cardiac condition or disease. Recent advances have made the device smaller, more effective and often unnoticeable to both the patient and the public. Consult your physician for more information about whether an ICD is right for you.