Prime Minister Ariel Sharon will undergo a catheterization procedure within three weeks to repair a small hole in his heart that apparently led to a minor stroke, his doctors said Monday.

Dr. Haim Lotem, head of cardiology at Jerusalem's Hadassah Hospital, said the hole, which is less than an eighth of an inch wide, is a minor birth defect found in 15 to 25 percent of the population.

He said doctors plan to use a catheter to insert an "umbrella-like" device to seal the hole in the wall between the upper chambers of Sharon's heart. The procedure, guided by a small camera inserted through the esophagus, is routine, doctors said.

They said Sharon will be given a mild anesthetic to relax muscles and will be partially sedated during the treatment. Patients undergoing such catheterization retain consciousness.

The hole was detected in testing following Sharon's Dec. 18 stroke. Doctors concluded the blood clot that caused the stroke passed through the hole and lodged in a cranial blood vessel, briefly restricting the flow of blood to the prime minister's brain.

Sharon is being injected with a blood-thinning medication Clexan twice a day until the heart procedure, Lotem said.

"From our experience this is something that is only a minor birth defect. It doesn't need to be treated unless it causes problems," Lotem told reporters.

Doctors said last week that Sharon suffered no lasting damage from the stroke. He was released from the hospital two days after the stroke and already has resumed his full workload.

Vice Premier Ehud Olmert would take over the prime minister's duties if Sharon were to become incapacitated during the catheterization. He did not take over during Sharon's stroke.

But the health scare raised concerns about the 77-year-old leader's ability to work as he runs for a third term, this time as head of a new centrist party. Opinion polls taken after the stroke have shown that Sharon remains the front-runner in the March 28 election.

Palestinian parliamentary elections are scheduled for Jan. 25.

Doctors met with reporters Monday following public pressure that Sharon's health records be made public.

Although Sharon had difficulty speaking during the stroke, neurological testing found that he recalled everything from the night of his admission, said Dr. Tamir Ben-Hur, neurology chief at Hadassah.

Doctors have ordered the overweight prime minister to go on a diet. Seeking to head off widespread speculation about his weight, Sharon's doctors said he weighed 260 pounds at the time of the stroke, and has lost 5 pounds since then.