FDA green-lights subcutaneous ICD

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The FDA has approved a subcutaneous implantable cardioverter-defibrillator (S-ICD) for the treatment of patients at risk for sudden cardiac arrest. The system helps to restore regular heart rhythms with leads implanted subcutaneously instead of connected into the heart.

The S-ICD system uses a lead that is implanted under the skin along the bottom of the rib cage and breast bone. Because the lead is placed under the skin rather than through a vein into the heart, a physician can implant the device without accessing a patient’s blood vessels or heart and without the need for fluoroscopy.

In April, the FDA's Circulatory System Devices panel voted to approve the device in a 7-1 fashion.

The S-ICD system is manufactured by Cameron Health of San Clemente, Calif., which was acquired by Boston Scientific in June. The S-ICD system has been distributed commercially in certain countries in Europe and New Zealand since 2009.

The S-ICD system is intended to provide defibrillation therapy for the treatment of ventricular tachyarrhythmias in patients who do not have symptomatic bradycardia, incessant ventricular tachycardia or spontaneous, frequently recurring ventricular tachycardia that is reliably terminated with antitachycardia pacing. It is approved only for patients who do not require a pacemaker or pacing therapy.

“The S-ICD system provides an alternative for treating patients with life-threatening heart arrhythmias for whom the routine ICD placement procedure is not ideal,” said Christy Foreman, director of the Office of Device Evaluation at FDA’s Center for Devices and Radiological Health, in a release. “Some patients with anatomy that makes it challenging to place one of the implantable defibrillators currently on the market may especially benefit from this device.”

The FDA reviewed data from a prospective, non-randomized, multicenter clinical study in which 304 of 321 patients were implanted with the S-ICD system. At the time of implantation, the investigator tested the effectiveness of the device by inducing heart arrhythmias. The S-ICD system was successful at converting all abnormal heart rhythms that it detected back to normal rhythms.

Investigators followed these patients for six months following implantation, during which time the device detected and recorded 78 spontaneous arrhythmias in 21 patients; all arrhythmias were either successfully converted back to normal by the defibrillator or resolved on their own. Because the S-ICD System memory stores data from only the 22 most recent arrhythmia episodes, there may have been other detected episodes that could not be analyzed by investigators.

The FDA reviewed safety data based on the entire 321-patient study population to identify complications that can occur during and after implantation of the S-ICD system. The most common complications included inappropriate shocks, discomfort, system infection and electrode movement, which required repositioning.

Eight patients died during the study; however, evaluators not involved with the study could not definitively attribute the deaths to the S-ICD system. Eleven patients required the removal of the device, and 18 had discomfort that was resolved without repositioning the device or surgery. At the end of six months, more than 90 percent of patients had no complications.

As part of the approval, the FDA is requiring Cameron to conduct a postmarket study to assess the long-term safety and performance of the device and to assess differences in effectiveness across genders. The study will follow 1,616 patients for five years.

Natick, Mass.-based Boston Scientific expects to begin a phased launch of the S-ICD system that will expand over time as medical professionals are trained on the use of the system.