A plan to spend $74 million at the Washington Hospital Center for a heart institute, a tower filled with private rooms and renovation of operating rooms has drawn fire from health planners, who say the proposal is out of step in a city where empty hospital beds are a costly and growing problem.

The plan comes at a time when the 922-bed hospital, suffering from declining use, has closed 117 surgical beds temporarily because they were empty and laid off some 90 employes because of low occupancy. Health planners estimate that by next year there already will be 659 too many hospital beds in the city.

Corporation officials said the improvements are needed because of the "general obsolescence" of the 25-year-old hospital and to compete for patients with newer, more modern suburban hospitals. The shift to private rooms is a response to patient requests, they said.

Hospital unions, the local Blue Cross-Blue Shield plan and citizens' groups also have attacked the project, saying it is too expensive and inappropriate. Major improvements in District hospitals, such as this one, may make the city's hospitals "unaffordable," said a spokeswoman for the Blue Cross-Blue Shield insurance plan.

Some groups claim poor patients and the elderly would be forced out of the hospital if a large portion of the beds became private, as is planned. Government-paid health care does not pay for private rooms, except under limited circumstances.

The plan is the costliest ever to be submitted to the D.C. State Health Planning and Development Agency, which is responsible for approving all spending for health facilities in excess of $600,000. Its fate is important for all area hospitals thinking about ways to attract patients in an era of tough new federal rules on hospital usage.

The project "represents a major element in our strategy to stabilize the loss of market share to other, more modern facilities," said Clarence Brewton Jr., director of planning for the Washington Healthcare Corporation, the hospital's parent organization.

He said the hospital's low occupancy -- a disputed figure, but below the 80 percent required by health planners for expansion considerations -- is related to its physical problems. "Patients are expressing a preference for institutions with more modern amenities," he said. Added John Green, vice president for planning and marketing for the corporation, "We do need larger patient rooms."

The plan would convert 240 semi-private rooms into new beds in a four-story tower. A majority of the beds, 160, would be in private rooms, a situation that the corporation said would cut nursing costs and the health planners said would raise them.

Also proposed are 17 new operating rooms, a relocated emergency room and a heart institute, which would consolidate all the hospital's cardiac services.

The cost of the project would raise patients' bills by $34 a day by its completion in 1989, according to hospital figures. This amount would be dwarfed by other expected increases that would come from inflation, Brewton told the health agency.

In their application, the hospital's corporate planners complained that corridors and operating rooms are crowded and said there is evidence of roaches, mice and rats in the building. There also is an "unpleasant environment and long waits in the emergency room" and difficulty in scheduling operations because of the crowded conditions. They also complained that exhaust from trucks at the loading docks and from the cafeteria and hospital incinerator is not escaping properly and that the same elevators are used for food, patients, laundry, visitors and staff.

The health agency's staff review concluded that the hospital should withdraw its application, saying that the bed replacement proposal is "unacceptable" and would lead to higher rates that would keep patients away. An advisory subcommittee voted 2 to 1 to reject the plan, which will reviewed by the agency's full advisory body on Thursday night.

The health planner's report said that Washington Hospital Center has had an occupancy rate of 73 percent for the last five months, well below the 80 percent level the agency set as a benchmark for facilities wanting to expand.

Further, it said the corporation's "primary purpose" in spending $2.3 million to relocate the hospital's cardiac services and to establish a heart institute was not to improve patient care but "for marketing services." It noted that corporate officials said the hospital has lost some of its heart patient business because of increased competition from George Washington University Medical Center, Georgetown University Hospital and Fairfax Hospital.

Faced with this negative preliminary review, the hospital is considering its options, said Green, of the planning staff. Withdrawal of the plan is one option, he said. Another "fallback" possibility, according to the minutes of a hospital planning subcommittee, is to educate "community members, Advisory Neighborhood Commissions, and Mayor Barry" about the value of the project.

Green said the hospital corporation has not yet decided how to proceed with the plan, which he said originated before the overbedding situation in the District grew to its present size.

The hospital corporation and the health planning agency have faced off before. In June 1983, when the agency discovered a two-story, $4.5 million parking garage was being built on the hospital grounds without approval, it sued the corporation for not seeking permission. The corporation's defense was that it is not a health facility, it merely owns one.

A Superior Court judge didn't settle the semantics issue, but required the corporation belatedly to submit an application and told the agency not to let this case prejudice its judgment on future projects.

Whatever the outcome in the current tussle, the process has yielded at least one bonus for poor patients.

One of the citizens' groups arguing against the project, The Coalition for Financial Accountability, found that the hospital was not following federal guidelines and poor people were not finding out about the hospital's obligation to provide a certain amount of free care. In response, hospital officials recently promised to reeducate the staff and print a manual on its free care policies.