FORT LAUDERDALE, Fla. – A kind of pacemaker for the tummy, an implanted electrical device that fools the body into feeling full, appears to be an effective alternative to radical digestive surgery for helping obese people shed large amounts of weight.

If it proves out in larger studies, the experimental device could offer a new way to help very large people slim down when they cannot lose weight on diets or with appetite-suppressing drugs. Researchers Sunday presented preliminary data on the usefulness of the approach, which has already been tested on 450 people to show its safety.

Surgical techniques that shrink the stomach and reroute the digestive tract are the only highly reliable way to make obese people lose weight. However, this is major surgery that carries significant risk, including a 1 percent chance of death, and researchers are searching for ways to do the job more safely.

The new device is called an implantable gastric stimulator and is similar to a cardiac pacemaker. But instead of stimulating the heart, this one is attached to the wall of the stomach and is intended to reduce feelings of hunger.

The researchers implanted the devices in 30 obese women and men whose average weight was 242 pounds. Their average body mass index, or BMI, was 42. The healthy cutoff for the height-to-weight ratio is 25; 30 is considered obese.

After a year with the implant, two-thirds of the volunteers had lost weight. The average was an 18 percent drop in their excess weight.

“The results are promising, although we still have a long way to go,” said Dr. Scott Shikora. “I believe in my heart this is a very exciting breakthrough in our field.”

Shikora, head of bariatric surgery at Tufts-New England Medical Center in Boston, presented the study in Fort Lauderdale at the annual scientific meeting of the American Association for the Study of Obesity. It was financed by the device’s developer, Transneuronix Inc. of Mt. Arlington, N.J.

The system uses an electrical pulse generator, a little larger than a silver dollar, that is placed under the skin in the abdomen and connected to the stomach with two wires. Implanting it takes less than an hour and is done as an outpatient laproscopic procedure.

“These early findings are exciting,” said Dr. Samuel Klein of Washington University, the obesity association’s president. “This is a potential new approach for the management of obesity that is separate from drugs or surgery.”

The device is already on the market in Europe but is still several years away from Food and Drug Administration approval in the United States. Steven Adler, Transneuronix’s executive vice president, said the company hopes in a few months to begin a study on 120 patients that will take two years to complete.

After installing the pacemaker, doctors crank up the power until patients feel unpleasant symptoms, such as nausea or cramps, then turn it down a bit until all sensation disappears.

“They don’t feel a buzzing or a pain,” Shikora said. “They just don’t have an appetite, or they get full very quickly. Some say, ‘I don’t know what it is. I just eat different now.”‘

Weight reduction varied widely. While about one-third in the study lost nothing, some had stunning success. One patient lost 104 percent of her excess weight, meaning she now weighs slightly less than her ideal.

Some have wondered whether the benefits are due to a placebo effect, since patients wanted to lose weight and knew they were being treated. However, one patient’s experience suggests not.

After getting the device, she failed for a year and a half to lose weight. Then doctors discovered one of the wires had come loose. After they reattached it, she dropped almost 100 pounds.

“If there was placebo effect, she should have lost weight at the get go, not after 18 months,” Shikora said.

The device is hooked near the stomach’s major nerves. Surgeons are still unsure exactly why it deadens appetite. Possibilities include an impact on the nerves, changes in digestive hormones or direct stimulation of stomach muscles.

So far, there have been no reports of deaths or serious complications resulting from the pacemaker, Shikora said.

Surgery to help people lose weight is now one of the fastest growing operations in the United States and will be done on an estimated 100,000 people this year. About 10 percent of patients have serious complications, such as hemorrhage, pneumonia, infection and blood clots.

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On the Net:

http://www.naaso.org/

http://www.transneuronix.com/

AP-ES-10-12-03 1422EDT