AC Milan striker Antonio Cassano underwent successful heart surgery this morning, the Italian club have confirmed. The Italy international had a procedure done at Milan\'s Policlinico hospital to repair an atrial septal defect in his heart. A statement from AC Milan read: \"\"The procedure on Antonio Cassano\'s patent foramen ovale finished at 8:35am and all has gone well. \"The cardiac procedure to close his patent foramen ovale in Antonio\'s heart was done under local anesthetic. The procedure was carried out by Professor Mario Carminati, and Milan\'s team doctor Rodolfo Tavana was present.\" Cassano was admitted to hospital last Saturday shortly after his team\'s 3-2 triumph at Roma after experiencing an ischemic cerebral damage. Tests this week confirmed the 29-year-old had a heart defect that needed treatment. AC Milan have yet to announce how long Cassano will be sidelined for but it is expected the former Real Madrid striker will be out until the new year.