KUALA LUMPUR, Jan 9 (Reuters) - Former Malaysian prime minister Mahathir Mohamad, 96, successfully underwent an "elective medical procedure" and is expected to be discharged in a few days, the National Heart Institute said on Sunday. "The procedure was uneventful and went as planned," the institute said in a statement. Mahathir was admitted into the institute on Friday, the second time in as many months that he has been hospitalised. Mahathir, who has a history of heart problems, was admitted on Dec. 16 before being discharged a week later. read more