Arnold Palmer has had a pacemaker implanted to correct an abnormal heartbeat.
According to his website, Palmer had successful surgery Monday at UPMC Presbyterian Hospital in Pittsburgh.
The 84-year-old Palmer was to remain in hospital overnight for observation.
He is expected to be released on Tuesday.
Golf Channel earlier this year produced a three-part documentary called Arnie, which was broadcast the week after the Masters in April.
The seven-time major champion remains one of the most endearing figures in golf.