WASHINGTON – The Food and Drug Administration said yesterday it has approved the first temporary artificial heart for use in patients at risk of dying within 30 days as they await a heart transplant.

The CardioWest Total Artificial Heart, manufactured by SynCardia Systems of Tucson, Ariz., takes over for the patient’s failing heart, restoring normal blood pressure and shoring up such vital organs as the kidney and liver. The “bridge” device is intended to help keep patients alive long enough for a heart transplant.

An FDA advisory committee in March recommended that the agency approve the device with caution, since complex surgery to install the device raises the potential for such complications as infection, bleeding, and stroke. Despite those risks, the panel found the device to have benefits for a small number of patients with no other choice.

The FDA approved the temporary artificial heart for patients awaiting heart transplants who don’t respond to other treatment and who are likely to die within 30 days due to nonreversible bi-ventricular failure. In such cases, patients typically are short of breath, even while resting, because their weakened hearts cannot efficiently pump blood.

Donna-Bea Tillman, director of the FDA’s Office of Device Evaluation, said the artificial heart would be an option for a very small group of patients, perhaps 100 a year in America.

Of 2,200 patients who get heart transplants each year, roughly 500 need some temporary assistance to ensure they’re still alive when the donor heart arrives. Within the group of 4,000 waiting for heart transplants, 100 have nonreversible failure affecting both the left and right sides of their heart.

SynCardia’s clinical trials looked at using the artificial heart in 81 patients eligible for transplants at five medical centers. All the patients had severe bi ventricular heart failure.

After receiving the artificial heart, 79% of those patients remained alive long enough to receive a donor heart. The average patient lived an additional 79 days, and the longest lived for 400 days before heart transplantation, the company said.

The most common adverse events were infection, affecting 72% of patients, and bleeding, suffered by 42% of patients. One-quarter of the patients suffered a neurological event like stroke. The device malfunctioned in 18% of patients.

Because the clinical trial enrolled so few people, the FDA is requiring the company to monitor an additional 50 patients for one year after they receive the implant.

The heart is implanted in the patient’s chest to replace the bottom half of the heart. It’s sewn to the remaining top half of the heart. Tubes connect the device to a console that supplies power and monitors the device’s function. The cost of the device and its components is about $100,000.

Dr. Marvin J. Slepian, SynCardia president and chief executive officer, called the FDA approval a “medical milestone” some 40 years in the making.

Bill Wohl, of Scottsdale, Ariz., credits the device for saving his life.

A massive heart attack at age 52 destroyed much of Mr. Wohl’s heart. After suffering later infections and pneumonia, he was transferred to the University of Arizona, where his heart and major organs failed. He had a CardioWest device, then experimental, implanted in September 1999. On February 22, 2000, the device was replaced with the heart of a 36-year-old accident victim.

This fall, he competed in Olympicstyle events for transplant recipients in Australia, snaring nine medals in cycling, swimming, and track events.

“Thank God for the CardioWest,” said Mr. Wohl, 58. “It kept me alive for that six-month period.”