Former President Clinton (search) was alert and talking on Tuesday, a day after undergoing a heart operation to bypass four severely clogged arteries.

Clinton remained in intensive care at New York Presbyterian Hospital/Columbia (search) and was "resting comfortably," according to a statement by his office.

"He is awake and alert and talking with his family," the statement said.

Doctors said the former president was taken off his respirator Monday night, a crucial step in his recovery. "He's sitting up, talking, and he's having a normal amount of discomfort, but he's actually doing just fine," Dr. Craig R. Smith, the hospital's chief of cardiothoracic surgery, said in a televised interview.

A hospital source who spoke to The Associated Press on condition of anonymity also said Clinton was taking liquids.

The source described the scene at the Manhattan hospital as swarming with Secret Service (search) and hospital security personnel.

Clinton's doctors will decide when he can be moved out of the intensive care unit. It was possible he would go to the hospital's McKeen Pavilion, where patients are treated to a piano player at a daily complementary high tea. Other perks include meals prepared by a gourmet chef and concierge service.

Clinton was expected to leave the hospital in four or five days.

Doctors performed the four-hour quadruple bypass operation on Monday and found that Clinton's heart disease was extensive, with blockages in some arteries well over 90 percent. Doctors said Clinton was in grave danger of suffering a heart attack in the near future.

Clinton, 58, went to the hospital last week after complaining of prolonged chest pain and shortness of breath, but doctors said those symptoms were actually present for several months. They said he had blamed them on lapses in his exercise routine and acid reflux.

In bypass surgery, doctors remove one or more blood vessels from elsewhere in the body — in Clinton's case, two arteries from the chest and a vein from the leg — and attach them to arteries serving the heart, detouring around blockages.

Clinton had planned to campaign for Democratic presidential candidate John Kerry, but the recovery will take him off the stump with just eight weeks left until the election.

It is "too soon to know what will be possible," said Jim Kennedy, Clinton's spokesman. "As the doctors said, it will be two to three months before he is 100 percent recovered."

Before the surgery, Clinton had been scheduled at a book signing of his new memoir in Baltimore and a book party in Washington, D.C., on Tuesday, Kennedy said.