Defibrillator Placed Just Below The Skin Deemed Safe, Effective
August 27, 2013

Defibrillator Placed Just Below The Skin Deemed Safe, Effective

Brett Smith for - Your Universe Online

A team of international scientists has just successfully tested the safety and efficacy of a new type of defibrillator that is implanted just under the skin.

According to a report on the device, published in the journal Circulation, the state-of-the-art device can detect dangerously irregular heart rhythms and administer shocks to return a normal rhythm without wires directly touching the heart.

The new device, called a subcutaneous implantable cardiac defibrillator (S-ICD), represents an improvement on traditional implantable cardiac defibrillators (ICDs), which use electrical wires inserted into blood vessels that connect to the heart.

Doctors are able to insert the new device under the skin along the left side of the breast bone without using X-ray guidance. The S-ICDs have reduced concerns about broken wires, blood vessel damage, infection and scarring that are associated with the traditional devices, the researchers said.

"Defibrillation has repeatedly proven to be a great asset in prolonging the lives of cardiac patients, but there are still some risks to address," said study author Dr. Martin C. Burke, a professor of medicine and director of the Heart Rhythm Center at the University of Chicago. "This new system was developed over a dozen years to combine some of the best aspects of traditional implanted ICDs and external defibrillators."

The new device was tested in a 33-site study that included 330 patients, 96 percent of whom had the S-ICD implanted. At a follow-up visit, approximately 11 months later, 21 patients had spontaneously developed 38 episodes of heart-rate difficulties. All were successfully corrected by the device. However, 41 patients in the study received unwarranted shocks that weren't preceded by a dangerous heartbeat.

The device was able to pass safety and effectiveness benchmarks set by the Food and Drug Administration for a new medical device. Ninety-nine percent of patients with the device remained complication-free after 180 days – surpassing the FDA standard of 79 percent. When the device was tested by an intentionally-produced irregular heart rhythm after implantation, it was able to detect and correct the issue 100 percent of the time – surpassing the FDA standard of 88 percent.

Study researchers said they plan to follow S-ICD patients over time to see if the device maintains its initial standards. They also made plans to compare the performance of the S-ICD to a traditional ICD.

The scientists added that patients with certain types of pacemakers or with symptoms connected to a slow heartbeat should not use the device. Candidates for the S-ICD will be determined from information on health registries and could include those on dialysis or with birth defects that affect the heart.

"The S-ICD is not a replacement for other defibrillators," Burke said. "For some patients it will be ideal, for others inappropriate, and the vast proportion in the middle will be able to select the type of system they want.”

The new device has been available in Europe and New Zealand since 2009. It was granted FDA approval for use in the United States in 2012.