Barney B. Clark, who has survived for a week with the world's first permanent artificial heart, today showed "cautious improvement" from seizures suffered Tuesday morning, University of Utah officials said.

"He continues to liven up," said Dr. Chase Peterson, university vice president for health sciences, but Clark is not yet completely conscious and remains in critical condition.

Medical tests continued to show improvement in Clark's body chemistry, a problem that doctors believe contributed to the massive seizure he suffered just before dawn two days ago. It was followed by small seizures or involuntary shaking of his left leg over a two- to three-hour period.

The after effects of the seizure itself, a "numbing" of Clark's nervous system, probably account for his continued deep sleepiness, since sedative drugs should have worn off, Peterson said.

Hospital officials said that in the week since the 61-year-old retired Seattle dentist received his plastic-and-metal implant, the heart hasn't missed a beat.

The chemical imbalance that may have led to the seizures seems to be improving, Peterson said, and "kidney function is nearing the normal range." A blood coagulation problem seems to be "bottoming out," an indication of a "rejuvenation process," he said.

All blood cultures, or tests, "rule out infection of the blood stream," but infection will continue to be a major concern, Peterson said. Clark has again been put on antibiotics to prevent infection.

His body salts, or electrolytes, which are crucial to maintaining proper body chemistry, appear to be in the "normal range" and his breathing is improving. However, Clark will remain on a respirator until he is fully alert, Peterson said.

His blood pressure is now "a little higher" -- at 150 over 95. This is about normal for a man his age but higher than it had been in recent days. This is a purposeful choice by doctors, who can regulate blood output using the external power system attached to Clark's mechanical heart.

Clark continues to receive a liquid meal through a tube in his stomach. It supplies about 1,000 calories a day. Peterson said that doctors plan to push that up to more than 4,000 calories a day to help the "healing process."

He is also receiving plain water and potassium salt to help the chemical and fluid balance and ward off further seizures. A low dose of the anti-seizure medication Dilantin is now being given to ward off additional seizures, Peterson said. He added that an EEG -- electroencephalograph or brain wave -- reading showed no abnormal activity and appeared to confirm a "quieting process" of Clark's nervous system.

Peterson said Clark appears to have suffered no permanent brain damage from the seizures, but this can not be ruled out until he is fully conscious.

He noted that the retired dentist had indicated once again to nurses this morning that they would have to brush his teeth a second time because the first effort "wasn't quite to his satisfaction."

Clark and his family, who have received get-well wishes from people around the world, also received a telegram from the White House, signed Nancy and Ronald Reagan.

"God bless you and keep you. Our hearts and prayers are with you and your family," it said.