Muralitharan, the leading wicket-taker in international cricket with 1,347 scalps, was admitted in Apollo Hospital, Chennai, for cardiac evaluation on Sunday.
The former Indian captain has been advised to be on medication and follow a strict routine for the next few months.
Two more stents were implanted to clear his clogged coronary arteries.
The former Indian captain is stable, doctors said.
The 61-year-old former Indian skipper underwent angioplasty last week after suffering a heart attack. He was discharged from the hospital a couple of days later.
He was admitted to the Fortis Escorts Heart Institute in South Delhi after suffering a cardiac arrest last Thursday, following which he had undergone angioplasty as a treatment.
The 61-year-old felt uneasy on Thursday following which he was taken to a hospital in New Delhi.
The 50-year-old from Trinidad, considered one of the greatest batsmen to have played the game, was admitted to the Global Hospital in Parel amid speculation that chest pain was the reason for his uneasiness.