JACKSON (AP) — Doctors were to implant a cardioverter-defibrillator, a small battery-powered electrical impulse generator, into the heart of Jackson Mayor Frank Melton on Wednesday.

The surgery was to take place at St. Dominic/Jackson Memorial Hospital, where Melton was taken Monday after fainting at a ceremony.

“The bottom line is that it is a means of monitoring the function of his heart,” former mayor and Melton attorney Dale Danks Jr. said Tuesday. “(Melton) should be incapacitated for half a day after surgery but is anticipated to be back to work shortly thereafter.”

Melton, 58, fainted Monday during a swearing-in ceremony for county officials at the Hinds County Courthouse. He was helped into a jury room, where he was attended to by paramedics before leaving the courthouse unassisted.

Melton flew to Texas a year ago this month to have a pacemaker implanted to regulate his heartbeat. While there, doctors discovered arterial blockage and instead had to perform double-bypass surgery.

Both pacemakers and defibrillators are electronic devices used to treat heart-rhythm disorders. Pacemakers are usually implanted when a heart beats too slow, either all the time or occasionally, said Dr. John Payne, director of cardiac electrophysiology at the University of Mississippi Medical Center.

Defibrillators are generally used for people who have either survived or are in danger of suffering cardiac arrest, the most common cause of death in the Western world, Payne said.

A defibrillator provides a reviving shock to the heart when it beats out of control, Payne said.

At rest, a normal heart may beat about 60 times a minute. A heart goes into ventricular fibrillation, or cardiac arrest, when it beats nearly 300 times a minute, he said. The condition can be caused by coronary blockage or heart disease, he said.

A defibrillator also can act as an emergency pacemaker, Payne said.

Payne said most patients do not keep both a defibrillator and a pacemaker since the first can serve a dual purpose.

City spokeswoman Goldia Revies did not answer questions about Melton’s health Tuesday.

“He’s asked us not to release any information about the details of his condition,” Revies said. “And I felt like we should respect that. We have not released any information that confirmed or denied anything because when he’s ready to, then we will do that.”