January 4, 2006. Copyright, 2006, Graphic News. All rights reserved Operation on Sharon to seal hole in his heart LONDON, January 4, Graphic News: Israeli Prime Minister Ariel Sharon is scheduled for heart surgery to repair a hole in his heart on Thursday at Hadassah University Hospital in Jerusalem. The tiny hole between the chambers of the prime ministerÕs heart is believed to be responsible for the mild stroke he suffered in mid-December. Professor Haim Lotan, head of cardiology at Hadassah, said the hole -- known as a patent foramen ovale (PFO) -- which measures less than an eighth of an inch (2mm), is a birth defect found in 15-20 percent of the population and often goes undiscovered. A PFO is a defect in the septum, the wall between the two upper chambers, or atria, of the heart. Incomplete closure of the atrial septum before birth results in the creation of a flap or valve-like opening. When a person with a PFO creates pressure inside his or her chest -- such as when coughing, sneezing, or straining -- the flap can open and blood can flow in either direction directly between the right and left atrium. When blood moves directly from the right to the left atrium, it bypasses the filtering system of the lungs which removes debris harmlessly. If small blood clots are present, they can pass through the left atrium and lodge in the brain, causing a stroke. Sharon, 77, who was hospitalized for two days after the December stroke, will be treated using cardiac catheterization -- a minimally invasive procedure in which a long, thin tube called a catheter is guided into the heart through the bodyÕs blood vessels. Using the catheter, doctors will put an umbrella-like device over the hole to seal it, Dr. Lotem told reporters. A small camera inserted through the oesophagus will guide the doctors, he said. The treatment, which will be performed under anaesthesia, should take about half an hour, allowing Sharon to resume his duties the same day and leave hospital on Friday. The procedure to seal the hole will almost eliminate the risk of a stroke similar to the one Sharon suffered on December 18, said Dr. Lotem. /ENDS