Streaga was a 27-year-old wild mustang who had suffered from heart problems. But unlike human heart patients, there was nowhere she could be taken for treatment. One day she fell to the ground, breathing hard and obviously in pain. It was a heart attack.

That was three years ago. Doctors had to make a "stall call" at the Potomac Equitation Farm in Centreville. Streaga was put to sleep.

Even today there is little chance of saving horses like Streaga; the sophisticated type of hospital care necessary to treat heart ailments and other complex illnesses isn't available in this area.

But by 1983, advanced medical care for horses will be available in Northern Virginia. Local horse owners will be able to send their horses to the Marion DuPont Scott Equine Medical Center in Leesburg, to be operated by the Virginia-Maryland Regional College of Veterinary Medicine. It will be the first university-affiliated veterinary hospital in the eastern United States dedicated exclusively to the care and treatment of horses.

Groundbreaking for the $6.5 million hospital is set for 2 p.m. Sunday. The medical center is scheduled to open in the spring of 1983.

Located in the heart of Northern Virginia's horse country, the center will be named after the Virginia horsewoman who donated $4 million toward the project: Marion DuPont Scott. The other major benefactor is the Westmoreland Davis Memorial Foundation, which donated 200 acres for the center at Morven Park, the estate of the late Virginia governor Westmoreland Davis.

The medical center initially will be able to house 30 horses; eventually it will expand to 100 stalls. It will provide facilities for examinations, surgery, intensive care, radiology, physical therapy and pathology. There will be a medical records section, a pharmacy and administrative offices.

When complete, the equine center will be linked by computer to the college's teaching hospital in Blacksburg, providing a medical information service similar to the one for human diseases at the Center for Disease Control in Atlanta, according to Mary Mitchell, a spokesman for the year-old college.

Mitchell said the hospital also will have research facilities that could make it something of a Mayo Clinic for horses. It will provide clinical training for veterinary students as well.

Veterinarians and stable owners in Northern Virginia and Maryland say they look forward to the day they can refer emergency cases and difficult surgery to the center.

Lorelei Novak, stable manager at Potomac Equitation Farm, said most of the medical care for the farm's 22 horses is provided at the stable. But for patients like Streaga, the hospital might make the life or death difference, she said.

Area horse owners now send injured or ill horses to New Bolton Center in Pennsylvania, a large animal hospital associated with the University of Pennsylvania, or to a private equine clinic in Charlottesville, which is not equipped to provide the comprehensive medical care many horses need, Mitchell said.

"This hospital is needed simply because we don't have one now," said Daniel Van Clief, a Virginia horseman from the Charlottesville area and a former member of the Virginia House of Delegates. "A lot of people in Virginia make their living from horses. It would be a great benefit to the owners to have such a facility."

Van Clief said the hospital also is needed by the veterinary school, run under the auspices of Virginia Tech and the University of Maryland.

"You cannot train a doctor without having hospital facilities. Without this center there would be no place for equine veterinarians to train," said Van Clief.