Cheney spokeswoman Lea Anne McBride said Cheney was taken to the hospital at 3 a.m. Doctors found his EKG, or electrocardiogram, unchanged and determined he was retaining fluid because of medication he was taking for an undisclosed foot problem.
Cheney, who has a long history of heart problems and has a pacemaker, was placed on a diuretic at the hospital.
McBride would not say what was wrong with Cheney's foot. The ailment forced the vice president to use a cane Friday.
CBS News chief White House correspondent John Roberts reports that sources familiar with the Vice President's medical condition say "he has occasional bouts with inflammation in his left foot, sometimes in the heel, which has been diagnosed as tendonitis, sometimes in the joint of his big toe, which has not been definitively diagnosed."
Some doctors have suggested it might be gout, and Cheney's personal physician, Dr. Gary Malakoff of George Washington Hospital, said back in 2000 that, in the past, Cheney has had several minor episodes of "gout of the foot," reports Roberts.
However, sources close to Cheney said he does not suffer from the acute pain usually associated with gout, nor does he have raised levels of uric acid in his blood, which is also associated with gout, Roberts added. Other doctors have suggested that osteoarthritis is the cause.
According to WebMD, gout is a form of arthritis that causes sudden, severe attacks of pain, tenderness, redness, warmth and swelling (inflammation) in some joints. It usually affects one joint at a time.
"He's doing fine," President Bush told reporters during a visit to a Maryland elementary school. "I talked to him this morning. His health is good. He'll be coming in to work a little later on today."
Mr. Bush's doctor notified him of Cheney's hospitalization early Monday morning before the president reported to the Oval office, said White House spokesman Scott McClellan. The president called Cheney after the vice president was released from the hospital and returned to his residence, and after Mr. Bush had breakfast with, McClellan said.
McClellan bluntly dismissed any question of Cheney's future in the administration, saying the president was "absolutely" not considering replacing the vice president.
"The vice president's doing a great job on behalf of the American people," he said. "He's a very important member of the team."
McBride said the foot condition was not related to surgery last September to repair aneurysms behind both knees or the 64-year-old vice president's lengthy history of heart problems. He has had four heart attacks, quadruple bypass surgery, two artery-clearing angioplasties and an operation to implant a special pacemaker in his chest.
It was unclear exactly what medication Cheney was taking for his foot ailment, but the usual course of treatment for gout is non-steroidal anti-inflammatories, says Roberts. A side effect of commonly used anti-inflammatory drugs is fluid retention, which can cause swelling and shortness of breath and strain the heart muscle.
Fluid can also leave the circulatory system and accumulate in various parts of the body, including the lungs, which can cause a shortness of breath.
All anti-inflammatory drugs — popularly known as NSAIDs, non-steroidal anti-inflammatories, including such drugs as ibuprofen and naprosyn — can cause that side effect. Now that Cheney has suffered it, he should avoid those medications, said Dr. Stuart Seides, associate cardiology director at Washington Hospital Center.
"It's not common, but it's certainly not rare," he said of the side effect. "Non-steroidals, many of which are over-the-counter, are not entirely benign drugs. The fact that they are sold over-the-counter does not mean that they don't have potent physiologic effects."
But once the side effect is treated, Cheney should have suffer no lasting harm from the episode, Seides said.
"It should have no effect on him or his long-term prognosis," he said.
The condition is usually treated with a diuretic.
Cheney has a long history of health problems and suffered his first heart attack in 1978 when he was 37. Ten years later, after his third heart attack, he had quadruple bypass surgery to clear clogged arteries.
Cheney, who has not suffered a heart attack since he became vice president in 2001, began a daily exercise program in 2000 and started eating healthier.
He quit smoking in 1978 and takes medication to lower his cholesterol.