Former President Bill Clinton (search), slim and smiling, returned to thank doctors and staff at the hospital where he learned in September that he needed quadruple bypass surgery.

"I was really delighted to walk in here instead of coming in a wheelchair and I'm even more delighted to be able to walk out," Clinton said Thursday as he helped open a new cardiac catheterization center at the Westchester Medical Center.

On Sept. 3, Clinton went to the medical center, which is not far from his home in Chappaqua, for an angiogram after suffering chest pains and shortness of breath. The test revealed narrowing of several vessels of his heart and he was transferred to New York Presbyterian Hospital/Columbia, where he underwent a quadruple bypass three days later.

"They showed me this really ugly picture of all this blockage I had," he told an audience of hospital workers that overflowed a small room into adjacent hallways.

Dr. Anthony Pucillo, who performed the test, told the former president that the publicity about his illness "contributed to more awareness of the importance and value of diagnosis and treatment among the general public."

Clinton said he had heard similar words from other doctors around the country and added, "This may have done more to affect as many people as almost anything I did when I was president."

He was given a private tour of the new catheterization center, which is designed to help both urgent and outpatient cases, then cut a red ribbon to formally open it.