03/05/2009 at 03:40 PM EST
Having been admitted to a south Florida hospital earlier this week, Robin Williams is "to undergo surgery for an aortic valve replacement," his reps announced Thursday.
An earlier statement about the 57-year-old, Oscar-winning comic actor said, "Williams was experiencing shortness of breath and is currently being evaluated by doctors who are recommending a week of rest."
Williams has canceled all performances of his one-man show, Weapons of Self-Destruction
, which was on a 80-city tour that started last September and is bound for Broadway in the spring. The tour is set to resume come the fall, say his reps.
"I'm so touched by everyone's support and well wishes," Williams said in a statement. "This tour has been amazing fun and I can't wait to get back out on the road after a little tune-up."
The aortic valve allows for blood flow from the heart's left ventricle to the aorta, which then distributes blood to the rest of the body. According to Stanford University Medical Center
, the goal of aortic valve surgery is to "repair or replace an aortic valve that isn't working correctly. ... When heart valves fail to open and close properly, the heart can become damaged. Heart valve problems are one cause of heart failure."
According to Williams's Web site
, he was to perform Wednesday and Thursday nights at the Seminole Hard Rock Hotel & Casino. He has also canceled shows for Friday at the University of Central Florida Arena in Orlando and Saturday's at Tampa's Sundome.
"Robin's rep called us the night before he was scheduled to perform at Hard Rock," Ryan Rogers, spokesman for the Seminole Hard Rock Hotel & Casino, tells PEOPLE. "The call came Tuesday night, during our Mötley Crüe concert. The rep said Robin needed rest and didn't feel well."