Former Mayor Ed Koch is being closely monitored in the intensive care unit at a Manhattan hospital, a spokesman confirmed Thursday.
The former mayor has been in and out of the hospital in recent weeks.
Shortness of breath landed him in the intensive care unit at New York Presbyterian Hospital Thursday afternoon.
A spokesman said doctors moved him to the unit to keep a closer eye on him, but added that Koch is conscious and is not on a respirator.
The city's 105th mayor was admitted on Monday. He was taken there for fluid around his lungs.
That same problem had him in the hospital for a week last month.
Koch has long been open about his health problems. While in his third term, he had a stroke. Then, after leaving office in 1989, he's had a number of medical issues, including a heart attack in 2000 and major heart surgery in 2009.
Doctors not involved in his care said past cardiac problems are continuing to pose challenges, leading to fluid backup around his lungs.
"It's a chronic condition, so it can be managed, but most patients don't completely recover," said Dr. Alex Reyentovich of NYU Langone Medical Center. "It tends to be a chronic condition that requires trips to physicians, a lot of self-care, a lot of self-maintenance, and it's a deadly condition. We don't like to think about it as a deadly condition, but it is. It's one of the leading causes of death, particularly in older patients."
Koch has kept up a positive outlook. In December he got a birthday cake after he was treated for a respiratory infection.
After leaving the hospital last Saturday, he sounded eager to return to work.
"Delighted to go home," he said. "There is nothing like home. I mean, this is a second home, but there's nothing like home. I'm going to do everything that Joe has told me to do, and I expect that I'll be in the office in the beginning of the week."