medical center, director of their cardiac lab. dr. schwartz described this evening repetitive symptoms at rest as being what initiated the contact for president clinton to his doctor. what does he really mean? >> well, rachel, the heart is supplied by a number of coronary arteries, three arteries, and as you know, six years ago the president had blockages in those arteries and therefore bypass grafts were put onto his heart. when there's an imbalance between the need for blood from the heart and the supply of blood, you get a feeling of like a cramp in the heart. exactly what the president was describing. a sense of discomfort. a sense of tightness. a sense of pressure. so it's just as he developed, as this graft closed and he became dependent again on the clogged up artery, his heart was not getting enough blood with even minimal exercise. >> how major a procedure was