Former President Bill Clinton is undergoing heart bypass surgery at a New York City hospital.
The surgery began around 12 hours UTC and generally takes four to five hours.
Mr. Clinton entered Presbyterian Hospital Friday after complaining of chest pains and shortness of breath. Tests found blockages in at least three coronary arteries.
The death rate from heart bypass surgery is relatively low -- less than four percent.
The Clinton family says that, while heart surgery is not something to look forward to, they feel lucky that the problem was detected before something more serious occurred.
Mr. Clinton is expected to make a full recovery, but will likely have to cancel some of the campaigning he planned to do for Democratic presidential nominee John Kerry.