AC Milan said forward Antonio Cassano has undergone a successful minor heart surgery.
The club said in a statement that the procedure to close a small opening in the Italy international's heart was carried out by Dr. Mario Carminati and that Milan physician Rodolfo Tavana was also present.
Milan announced on Wednesday that Cassano has a cardiac anomaly which caused a brain problem due to impaired blood flow.
The 29-year-old Cassano has been hospitalized since Saturday, when he was taken for tests after falling ill on the team plane following the team's 3-2 victory over Roma.
Milan vice president Adriano Galliani has said Cassano could be out from four to six months.