A cardiologist who served as dean of the Johns Hopkins University School of Medicine has died.

The school announced that Richard S. Ross, a cardiologist who also served as president of the American Heart Association in the early 1970s, died Tuesday. He was 91 and had been suffering from Parkinson's disease.

Ross was dean of the Johns Hopkins University School of Medicine from 1975 to 1990, the second-longest tenure in its history.

In 1974, he was one of three physicians asked by a federal judge to examine former President Richard Nixon to determine whether he was not well enough to testify during the Watergate investigations. Ross and his fellow physicians determined that Nixon was too ill to travel.

Ross was a graduate of Harvard Medical School.