President Peter Likins’ condition was upgraded from critical to serious yesterday at University Medical Center, the day after he had an emergency heart surgery that resulted from complications with his pacemaker.

Doctors said Likins, 69, is expected to recover quickly and to normal capacity, though it could take between six and eight weeks. It’s unclear if he will be able to return to work within that time, but Likins should be able to go home within a week, said Dr. Cristy Smith, the medical director of Cardiovascular Services.

Likins was rushed to UMC Wednesday when he began feeling ill and almost fainted. Physicians determined that the lead of his pacemaker had migrated and punctured a hole in an atrium and heart muscle, causing bleeding in the pericardium around his heart.

Doctors replaced the lead and drained the blood in a 1 1/2-hour surgery, said Smith, who performed the surgery. On Wednesday night, Likins was in stable but critical condition, but was upgraded to serious condition yesterday.

In Likins’ absence, his duties fell to Joel Valdez, the senior vice president for business affairs.

Valdez was not available for comment yesterday afternoon, but he will be working with Provost George Davis, the executive vice president, and Saundra Taylor, the senior vice president for campus life, to handle the administrative responsibilities, said Paul Allvin, the associate vice president of communications.

“”As we allow him time to recuperate, the three of us are in close communication to ensure the day-to-day business of the university is taken care of,”” said the vice presidents in an e-mail sent yesterday from the president’s office.

Davis was in Texas this week for business but was expected to return to Tucson last night, Allvin said. Davis will be the head administrator once he returns.

Allvin said compensating for Likins’ absence this week was not unusual because the same procedure occurs when he travels or takes a sick day.

The three vice presidents will meet soon to discuss the long-term effects of Likins’ absence and how to plan for the next few months, Allvin said.

Members of the UA community can send get-well letters to Likins at plikins@email.arizona.edu for when he returns.

Likins is planning to retire June 30, when Robert Shelton, the provost of the University of North Carolina-Chapel Hill, will assume the presidency.