New defibrillator goes under skin, not into heart

Rebecca Frost got her first defibrillator in 2002, after she collapsed from cardiac arrest in the parking lot of a Walmart near Asheville, N.C.

The battery-powered device, implanted in her chest, monitored the rhythm of her heart. Over the next year, it saved her life several times by sending electrical shocks through wires to her heart when it began beating dangerously fast.

More than a hundred thousand patients each year get implantable defibrillators to monitor their hearts. But the traditional models, which have wires threaded into the heart, can also cause problems.

The batteries have to be replaced periodically, and when Frost had that done, she developed infections in 2010 and 2011. After multiple rounds of antibiotics and two operations to have the devices removed, she said her doctors were "running out of options." Her heart had so much scar tissue they couldn't implant another device.

They sent her home with an old-style treatment — a vest with electrodes that monitored her heart from outside her skin.

Meanwhile, Frost's surgeon thought she might be a candidate for a clinical trial for a new type of defibrillator, with wires implanted under the skin but not in the heart.

Some of the testing for the new device was being done by Dr. Mark Kremers, an electrophysiologist with Mid Carolina Cardiology and Presbyterian Hospital.

Kremers was a principal investigator for the trial, which included 33 U.S. medical centers and 330 patients enrolled from fall 2011 to March 2012. He and his colleagues at Novant Health, which owns Presbyterian, enrolled 23 patients — the third most of any center in the study.

By the time Frost contacted Kremers, the study was finished, but the new device — a subcutaneous implantable cardioverter defibrillator made by Boston Scientific — wasn't yet on the market. Kremers helped Frost get the device under a "compassionate use" waiver from the Food and Drug Administration in April.

The FDA approved the new defibrillator six months later, in September, so it is now available through any doctor with appropriate training.

But not everyone is sold on the device. It "has not yet been shown to be safe and effective in a diverse patient population," Robert Hauser wrote in the January issue of the Journal of the American College of Cardiology.

Hauser, of the Minneapolis Heart Institute, has been a vocal critic of medical device companies. He noted that the new ICD has not been shown to be as good as the older ICD.

He said the technology is a promising one that could fill important gaps, especially by bringing it to countries where facilities to implant traditional devices are not available, but more data are needed first.

Kremers believes the new device is a significant improvement over the ones that required inserting wires into veins in the upper chest and into the heart. That carried the risk of damaging the heart or vessels.

Time will tell if infection rates decrease, but Kremers said infections will be easier to treat without wires in the heart. He said the new device could help 15 percent to 20 percent of defibrillator patients.

"I would categorize this as game-changing," he said.

10,000: The estimated monthly number of who receive a traditional implantable cardioverter-defibrillator (ICD). The American Heart Association says psychosocial support needed to adjust to life with an ICD is often overlooked after the devices are implanted. The AHA statement, published in a recent issue of Circulation, includes recommendations such as making sure ICD recipients and their families have a "shock plan," so everyone knows what to do if the ICD has to send a shock to a heart out of rhythm.

Reuters contributed to this report.

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