Israeli Prime Minister Ariel Sharon is to undergo a procedure to close a small hole which doctors found in his heart after he had a minor stroke.
Mr Sharon's health is an issue with elections due early next year
Chaim Lotem, one of the team of doctors, said the hole was a common minor birth defect.
He said it would be sealed with an "umbrella-like" device inserted by running a small tube through a blood vessel.
The procedure would take place in the next two or three weeks, he added.
At a news conference, Mr Sharon's doctors said they had concluded that the blood clot that caused the prime minister's stroke had lodged in the hole in his heart, restricting the flow of blood to his brain.
The prime minister was now taking blood-thinning medication until he underwent the heart procedure, Dr Lotem said.
Doctors have said that Mr Sharon suffered no lasting damage from the stroke, and that his blood pressure and cholesterol levels are normal.
He was released from hospital two days later and has resumed his full workload.
But the health scare has raised concerns about the 77-year-old leader's ability to continue in office as he runs for a third term.
Doctors have ordered him to go on diet. They said he weighed 118kg (260lb) at the time of the stroke, and had already lost 3kg (5lb) since then.
During the course of the press conference, the team of four doctors released Mr Sharon's health records, a first for an Israeli prime minister.
These say that the stroke that he suffered eight days ago was "very minor". Although Mr Sharon's powers of speech were affected for several hours, the records say, the stroke had no impact "on his memory and other faculties".
Mr Sharon left the ruling Likud party last month to form a new centrist party, Kadima.
His rival Binyamin Netanyahu subsequently won the Likud party leadership.
Mr Sharon has been prime minister since 2001, and polls suggest his new party is in the lead with an election due in March.
However, analysts say Kadima is built so completely around Mr Sharon that questions about his health are likely to become a significant election issue.