The president of Washington Hospital Center, the largest hospital in the Washington area, announced his resignation yesterday, sending another shock wave through the city's troubled health-care system.

The departure of Dunlop Ecker, 50, who joined the hospital eight years ago, comes amid turmoil within Medlantic Healthcare Group, the parent company, which has been struggling along with other health-care providers to cope with the rising cost of indigent care, declining patient revenue and what providers say is inadequate medical insurance reimbursement.

Medlantic is the District's largest health-care provider. Its three hospitals and 11 other health-care facilities employ more than 7,200 people. Medlantic provides health services to more than 250,000 people in the Washington area.

Kenneth A. Samet, a Medlantic official who has been executive vice president for system development and diversified business, will succeed Ecker.

Ecker, whose resignation takes effect Nov. 19, said his parting with the hospital and Medlantic was "amicable." He said he will remain at the hospital in an advisory role until early January.

Some physicians took another view of Ecker's resignation.

"I am a little concerned that Ecker may have become a sacrificial lamb whose head has been offered up to mollify the medical staff for problems that may have been as much creations of Medlantic as creations of Mr. Ecker," said Brandis Marsh, a member of the hospital's medical staff.

Those problems, according to Marsh and others, include the tensions that have reverberated through the hospital in recent months as physicians have challenged corporate actions, particularly concerning financial management.

Earlier this year, some doctors at the hospital hired an auditor to determine how much money was moving from the hospital to the corporation. The audit indicated that about $80 million had been transferred from the hospital to Medlantic over the past eight years, one source said.

Doctors still are trying to determine, sources said, if it would have been better for the money to remain with the hospital to pay for equipment and plant modernization.

A Sept. 25 memorandum from the hospital's medical board, a doctors' panel, to the board of directors of the hospital expressed concern that the hospital is deteriorating, that present financial restraints put patient care in serious jeopardy and that Medlantic investments are not proper or wise. "Physicians have gradually lost confidence in {Medlantic's} management abilities," the memo said.

Medlantic also has been buffeted by protests over its plans to transform Capitol Hill Hospital into a long-term care facility. About 600 workers at the hospital have received notice that they might be laid off Dec. 19.

Doctors, nurses, workers and community residents have united to try to save the hospital, arguing that it is needed and that it could be financially viable if managed properly.

At a hearing before a D.C. Council committee this week, Mark Brian Smith, a research analyst for the Service Employees International Union, testified that Medlantic has used Capitol Hill Hospital as a "cash cow," transferring $5.3 million from the hospital to Medlantic during fiscal 1982 to 1989.

Smith said the hospital made $12.2 million in profits from fiscal 1982 to 1989, but did lose money in 1988.

Medlantic Executive Vice President John L. Green, testifying at the same hearing, said Capitol Hill Hospital lost more than than $1.5 million in fiscal 1988, $5.1 million in fiscal 1990 and could lose $7.4 million by the end of the current fiscal year.

In early October, the Medlantic board voted to restructure its holding company into an operating company to streamline operations.

One effect of that action, some health care officials said yesterday, would be to provide Medlantic with tighter control over its hospitals and health-care groups.

Ecker said he was offered a position in the new structure but decided to leave for other opportunities in the health-care field.