He says he's uncertain when he'll return to manage the team. La Russa has been away from the White Sox since Aug. 30.
He rejoined the club on Sunday in Oakland to celebrate the A's retiring Dave Stewart's No. 34 jersey.
La Russa managed Stewart and was part of the tribute, but was not managing the White Sox in their game against the Athletics.
La Russa shared specifics of the procedure with The Associated Press after discussing his health before Chicago's series finale against the Athletics.
He is grateful to have had what he considered a relatively "simple" heart issue. The Hall of Fame manager turns 78 next month.