One day after undergoing open-heart surgery to replace a hardened aortic valve, former first lady Barbara Bush is making "remarkably good progress," according to her doctor.
"She's really made an excellent recovery," said Dr. Gerald Lawrie, the surgeon who performed the operation.
The aorta, the body's largest artery, is the main path that the heart uses to pump blood to the body. The hardening of the valve is typical of normal wear and tear on the heart of someone Bush's age.
A spokesman for President George H.W. Bush told ABC News that the 83-year-old former first lady took the procedure so lightly at first, she didn't even want to tell her children.
"This was a very calm, pleasant atmosphere that she created actually, by not bringing in her whole family," Lawrie said.
But according to the hospital statement, "a hardened aortic valve needs to be replaced because, when left untreated, it can result in heart failure or sudden cardiac death."
Dr. Tim Johnson, ABC News' medical editor, told "Good Morning America" today that Bush's complaint of shortness of breath is the most common symptom for people suffering with this type of heart disease.
"This is a very major valve," he said. "When it gets old and hardened and calcified … it doesn't work as well."
Johnson said a new surgery is being studied that could revolutionize this process and make for a much faster recovery. The surgery, he said, uses a catheter, inserted in the groin, to reach the heart.
If Barbara Bush had needed her surgery eight or nine months down the road, he said, she could possibly have been a candidate and wouldn't have had her chest opened.
Bush appeared to be in good health when she was last seen publicly at President Obama's inauguration in January.
This is the second time in four months she has been hospitalized. In November, she had surgery for a perforated ulcer after doctors said she described experiencing the worst pain of her life.
Bush was resting comfortably at a Houston hospital with her husband, former President George H.W. Bush, by her side, Bush spokesman Jim McGrath told ABC News.
"I am very impressed with and grateful to the wonderful team of doctors and nurses at Methodist Hospital who have helped Barbara," the former president said in a prepared statement. "We have every confidence she is in the best hands."
The former president's chief of staff, Jean Becker, described Mrs. Bush, 83, as "alert and funny" after the surgery.
Bush should be discharged in seven to 10 days, the hospital said.
In addition to the ulcer last year, Bush has sought medical attention in the past for a number of other issues, as well. In 1989, a thyroid condition known as Graves disease reportedly caused her to lose 18 pounds in three months.
She later began taking medication and, in 1990, received radiation therapy for her eyes as part of her treatment for this condition.
Earlier, she had received steroids to treat the condition, though her doctor later pulled her off the medication. Long-term use of steroids has been linked to the development of stomach ulcers.
ABC News' Dan Childs contributed to this report.