New wiring simplifies defibrillator implants

Ronald Grzymala, with cat Mitzi, received an under-the-skin ICD.
Ronald Grzymala, with cat Mitzi, received an under-the-skin ICD. (APRIL SAUL / Staff photographer)
Posted: March 17, 2011

Like many heart-failure patients, Ronald Grzymala was in a bind.

His weakened heart put him at risk of sudden cardiac arrest, so he needed to have a device placed in his chest that could jump-start his heart if it stopped. But he couldn't safely undergo the complicated implantation surgery because of other health problems.

Six months ago, the Southampton, N.J., resident found a solution at the Hospital of the University of Pennsylvania. He had an experimental implantable cardioverter defibrillator (ICD) installed during a simple outpatient procedure that took less than an hour and didn't even require X-ray imaging.

Like all ICDs, the new one has a small, battery-powered generator that can send an electric shock. But the new system eliminates the most difficult, breakable, malfunction-prone part of the conventional ICD - the electrical wires, or leads, that are threaded through a vein and placed in or on the heart.

Instead, the lead runs from the generator to the breastbone, where it is anchored with a few stitches. The device can detect heart stoppages without directly touching the organ, just as an electrocardiogram can capture heartbeats through electrodes placed on the chest.

Only three minor chest incisions are needed to place this under-the-skin, or subcutaneous, ICD.

"It's the only one I could have used," said Grzymala, 68.

The S-ICD, made by Cameron Health Inc., has already been approved in Europe. To get U.S. approval, the company is paying for a clinical trial under way at 30 U.S. sites, including Penn, Cooper University Hospital and Drexel University College of Medicine.

Even assuming the S-ICD proves to be as safe and effective as older systems delivered through a vein, it will not replace them.

The standard intravenous ICD can not only jump-start a heart with an electrical shock, it can provide pacing for a heart that beats too slowly or too rapidly.

The new subcutaneous system, in contrast, is only for a patient whose heart may suddenly stop beating, either because it is damaged and weak, or because an electrical abnormality triggers a chaotic quivering called ventricular fibrillation.

Still, eliminating the intravenous lead is likely to expand ICD usage, experts say.

No longer will implantation require a physician with specialized training, skill and equipment.

"It will certainly open [implantation] up to less-technically trained physicians, such as general cardiologists," said assistant professor Fermin Garcia, who is leading a trial at Penn. "And it's very easy to program."

What's more, the subcutaneous lead may be less prone to failure - or, at least, easier to replace if it does fail.

Studies have found that intravenous leads malfunction within five years in about 3 percent to 15 percent of patients. This may result in improper heart shocks that are painful, terrifying - and require another difficult surgery.

Intravenous lead defects may be due to a manufacturing problem, as with the Sprint Fidelis ICD that Medtronic voluntarily removed from the market in 2007.

Or, the lead may "fracture" at a pressure spot.

"There's a point where the lead has to go between two bones - a rib and the clavicle [collarbone]," Garcia said. "So you could raise your arm and crush the lead."

The implications of expanding the use of the lifesaving devices are unclear. On one hand, studies show that many patients who could benefit don't receive ICDs because of the surgical difficulties. On the other, a recent study found that many doctors are not strictly adhering to guidelines for implantation.

Between 2006 and 2009, the study found, 25,000 ICD implants - almost a quarter of the total - were done too soon after a heart attack, bypass surgery or heart-failure diagnosis. In-hospital deaths and complications were more common among these patients than those who fit the guidelines.

"Although there might be some future cost advantages and the availability of the totally subcutaneous systems might allow more physicians to implant the device, controversy still exists regarding potential benefits versus disadvantages," Andrea Russo, a cardiac electrophysiologist who is leading the S-ICD trial at Cooper University Hospital, wrote on a Heart Rhythm Society blog.

For Grzymala, the benefits were clear.

When his heart failure was diagnosed two years ago, the organ's pumping ability was less than a third of normal - a known risk factor for cardiac arrest. But he would also be at risk of deadly complications from ICD surgery - an open-chest operation, his cardiologist said - because of chest and neck radiation in 1995 to treat esophageal cancer.

"Once radiation burns your skin like that, it becomes damaged," Grzymala said. "If I get a cut in that area, it won't heal easily."

Although he doesn't remember the ICD surgery, done under sedation, his recovery was smooth. "I didn't even need any painkillers," he said. "And I'm not the bravest person."

Now, he enjoys being active, reassured that his heart has a fail-safe.

"I like to fish. I split my own wood. I shovel snow," he said. "I just have to take it slow."

Contact staff writer Marie McCullough at 215-854-2720 or mmccullough@phillynews.com.

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