UPDATE: Hospital officials later deemed the procedure "successful."
The singer is currently undergoing surgery in a Phoenix hospital to close a hole in his heart that doctors discovered last April.
The procedure follows a brain hemorrhage the Celebrity Apprentice star suffered last spring, which landed him in critical condition in the hospital.
What does this latest operation involve?
The Poison frontman will undergo a cardiac catheterization—which involves inserting a catheter into a vein in the groin and guiding wires and a closure device into the heart. Ouch.
Docs will work with the aide of cameras as they maneuver around and operate to close up the hole.
The closure device will remain in the rockers heart permanently and will prevent abnormal blood flow between the two chambers of the heart. Without this surgery, Michaels runs the risk of developing deadly blood clots and having a stroke.
This latest setback comes after a hard year for the 47-year-old, health-wise. Last April, after complaining of an excruciating headache, doctors discovered a massive subarachnoid hemorrhage—bleeding at the base of Michaels' brain stem.
Michaels had undergone an emergency appendectomy in San Antonio on April 12 and stayed in the hospital a few extra days under his personal doctor's supervision before moving to a rehab clinic specializing in treating diabetics.
We wish Bret a speedy recovery!
(Originally published Jan. 24, 2011, at 2 p.m. PT)