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Subcutaneous implantable defibrillator (S-ICD) a new technology that provides a gentler form of defibrillation therapy and new class of protection for patients in the event of an abrupt loss of heart function, known as sudden cardiac arrest (SCA). Most episodes of SCA are caused by the rapid and/or chaotic activity of the heart known as ventricular fibrillation.

During the procedure, the device – the S-ICD® System – is implanted just under the skin (subcutaneously) to help to restore the heart’s normal rhythm whenever it is needed, leaving the heart and blood vessels untouched. Unlike traditional transvenous implantable cardioverter defibrillators (ICDs), the S-ICD System doesn’t implant hardware – thin, insulated wires known as leads – into the heart. This device makes it possible to deliver a life-saving shock with less risk to the patient, while offering the same safeguards as traditional ICDs.

The S-ICD system has been widely studied and supported for its safety and efficacy, receiving its CE Mark in 2009 and regulatory approval from the Food and Drug Administration in September 2012. This less-invasive treatment is a new option for patients without venous access, those with high risk for infections and potentially younger patients who need long-term ICD therapy.

Other potential patient benefits include a decreased risk for systemic infections and clinical complications, prevention of any vascular injury as well as the preservation of venous access. Recent estimates show that approximately 850,000 people in the United States are at risk of sudden cardiac arrest, but remain unprotected without an ICD.

The S-ICD System from Boston Scientific has two main components:

  1.  the pulse generator, which powers the system, monitors heart activity, and delivers a shock if needed, and
  2.  the electrode, which enables the device to sense the cardiac rhythm and serves as a pathway for shock delivery when necessary.

Both components are implanted just under the skin—the generator at the side of the chest, and the electrode beside the breastbone. Implantation with the S-ICD System is straightforward and can be done using only anatomical landmarks, which removes the need for fluoroscopy (an X-ray procedure) that is needed in order to place the standard leads in the heart.

Heart Rhythm Conditions

If you have been diagnosed with heart rhythm problems, often called arrhythmias, you are at risk of cardiac arrest. Patients with ventricular fibrillation (VF), a fast and irregular heart beat due to an abnormal electrical signal in the lower chambers of the heart (ventricles) or ventricular tachycardia (VT), a fast, but regular heartbeat that begins in the ventricles, reduce the amount of oxygen to the heart. In extreme cases, this can be a life-threatening emergency.

A subcutaneous cardioverter defibrillator (S-ICD) is an implantable device that helps prevent ventricular arrhythmia, without touching the heart or veins. The unit is a small battery-powered electrical pulse generator with an electrode that constantly monitors your heart rhythm, instead of the heart beat like in traditional transvenous units. Complications with traditional ICD’s involve the leads that run from the device and deliver energy to heart muscle. Overtime these leads can lose their function, and even block blood flow. All of these cases require that the ICD be removed. This newer S-ICD, however, has no leads. Shocks are delivered wirelessly, eliminating this complication.

Advanced technology uses an algorithm to identify and classify heart rhythms, intervening only when it is appropriate. If VT or VF causes the heart to beat too quickly or irregularly, the S-ICD restores the rhythm using electric signal. When the heart rhythm returns to normal, the unit turns off the electrical intervention.

The S-ICD is placed on the side of the chest near your armpit. The procedure is done without using fluoroscopy, reducing radiation exposure for both patients and physicians. Traditional ICDs require fluoroscopy to guide the unit into place.

Learn What to Expect from S-ICD Implantation