The president of Brigham and Women's Hospital, a Harvard-affiliated facility, resigned this week after 19 months as chief executive officer of the hospital.

Dr. Robert G. Petersdorf will leave Brigham and Women's next fall to become dean and vice chancellor of health sciences at the University of California Medical School in San Diego. He was unavailable for comment yesterday.

Petersdorf has said that he is resigning both because he prefers to live on the West Coast--where he lived for many years before joining the Brigham and Women's staff--and because he believes he is better suited to running an academic department or a medical school than to heading a hospital, James P. King, assistant vice president for corporate communications at the hospital, said yesterday.

"To some people it was a shock, but we knew that he would feel more comfortable out on the West Coast," King said, adding that "it was no secret that he was somewhat dissatisfied out on the East Coast."

King also said that Petersdorf got involved in more day-to-day operations at Brigham and Women's than he had planned.

As president of the hospital, Petersdorf played an important role in merging the medical departments of Brigham and Women's and Beth Israel, another Harvard-affiliated hospital, last year, Eugene Braunwald, Hersey Professor of the Theory and Practice of Physics and head of the combined departments, said yesterday.

An expert in internal medicine and infectious diseases, Petersdorf was also "much involved" in combining the Boston Hospital for Women, Robert Breck Brigham and Peter Bent Brigham Hospitals to create Brigham and Women's, Braunwald said.

"The fact that he's a hard-driving person made it possible to get a lot of prima donnas to work together." Braunwald said, adding that Petersdorf will be "sorely missed."

Although King said that most heads of hospitals in the Boston area have held their posts for at least five years, Braunwald said that Petersdorf's leaving after less than two years should not hurt the hospital's administration.

A committee not yet appointed will search for a successor to Petersdorf, King said.