Nanostim’s Mini Wireless Pacemaker Shows Promise in Study

Nanostim Inc.’s miniaturized pacemaker, a device the size of a AAA battery placed entirely in the heart, appeared promising in its first human trials.

The device from Nanostim, a closely held company that St. Jude Medical has said it will acquire by year’s end, doesn’t have the wires typical of a pacemaker. Wires carry an electrical charge from a battery-powered generator in the chest to the ventricle to prompt a regular heartbeat. Nanostim’s device, threaded through the femoral artery into the heart, is powered by a built-in battery that can last eight to 17 years.

The lack of wires known as leads removes a source of complications since they can become infected, dislodged or damaged, said Vivek Reddy, director of electrophysiology at Mount Sinai Hospital in New York, who yesterday presented the findings with the first three patients at the Heart Rhythm Society meeting in Denver. The procedure doesn’t require surgery or leave scars or visible signs of the device, he said.

“This is a shift in how we think about pacing, but a lot of the technology -- the way it touches the heart and the way we deliver it -- has been worked out already,” Reddy said in a telephone interview. “In these patients, we placed the device properly and it was able to pace and sense appropriately.”

Rivals’ Efforts

Nanostim appears to be ahead of Medtronic Inc., the world’s biggest maker of heart-rhythm devices, and Boston Scientific Corp. in developing a leadless pacemaker, said Larry Biegelsen, an analyst at Wells Fargo in New York, in an April 11 note to investors. St. Jude, based in St. Paul, Minnesota, is an investor in Sunnyvale, California-based Nanostim and said last month it plans to acquire the company and begin selling the device in Europe by the end of the year.

St. Jude gained 1.6 percent to $43.10 at the close in New York. The device maker has increased 9.9 percent in the past 12 months.

About 700,000 pacemakers are implanted worldwide each year. In the U.S., only about 20 percent of them operate in just one chamber of the heart, like the Nanostim device, while in Europe it’s almost 40 percent, Reddy said. The company is working on advanced versions that can pace two chambers, he said.

Reddy, who serves as a consultant to Nanostim and holds stock options in the company, will present the results with additional patients tomorrow in another meeting session.

New Approach

The approach represents a new way to think about heart-rhythm devices and the research is among the most exciting being presented at the meeting, said John Day, director of heart-rhythm services at Intermountain Medical Center in Murray, Utah, and chairman of the panel that reviews scientific papers to be presented at the meeting. A wireless device may be particularly important for younger patients and athletes, whose activity can stress the leads, he said.

“For the most part, these devices are incredibly reliable,” Day said in a telephone interview. “The Achilles heel is the lead. Every time you move your arm, for example, you are putting some strain on the lead. With this device, it’s no longer hard wired.”

Researchers implanted the wireless pacemakers into three patients at Homolka Hospital in Prague late last year, successfully getting the miniature machines into the heart. In two patients the process went smoothly and the device worked properly right away. In the third patient, the doctors needed to reposition it three times until it was in the optimal position and pacing correctly. All three are still being followed.

The leads that accompany standard pacemakers often need to be repositioned when they are inserted, Reddy said. The fact that the researchers were able to do the same thing with the leadless device was reassuring, he said. In addition, the pacemaker has a “snare catheter” that can be used to remove the device from the heart without surgery if needed, he said.

U.S. Studies

Studies of the device in the U.S. may begin within the next year and take several years to complete, Reddy said. It’s not clear how many patients are needed in studies of the pacemaker to gain U.S. Food and Drug Administration approval.

Additional studies must confirm the devices will work for years, Day said.

“We need to make sure not only can it be implanted and done safely, but what we really need to know is how long this holds up,” Day said. “You trade the leads for a new set of problems. Now we are talking about wireless communication. It’s not fool proof either, but I believe this is the future.”

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