A 7-year-old boy, pulled with his dead brother from an icy pond after 45 minutes underwater, died early Tuesday after doctors struggled for more than 15 hours to save him.

Hopkins County Deputy Coroner Charlie O'Neal said Adam Bates was pronounced dead at 4:25 a.m. at the Regional Medical Center after his bodily systems collapsed.Doctors had hoped to save Adam and were encouraged that his heart had continued to beat after he was pulled from the pond.

The boys, given a holiday from classes Monday because of icy road conditions, ventured onto an ice-covered pond by their home near Anton, 6 miles east of Madisonville in western Kentucky.

They broke through the half-inch-thick layer of ice around midmorning and disappeared under 35-degree water, O'Neal said. Air temperature at the time was about 20 degrees.

When the boys' father went looking for them, he spotted footprints in the snow leading to the pond.

"The father found a sock hat that one of the children was wearing on the embankment leading to the pond," O'Neal said. "He then found footprints on the snow and a broken-through area where the footprints terminated."

The father waded into the 10-foot deep pond searching for his children while his wife called paramedics, said O'Neal, who also is director of the hospital's ambulance service.

Rescue workers arrived at the scene in nine minutes and fished the boys from the pond using grappling hooks.

"We're estimating they were under the water between 35 and 45 minutes," O'Neal said.

The boys were taken by ambulance to the medical center where their mother, Vicky, works as a nurse. The boys arrived at the hospital at 11:44 a.m.

Hopkins County Disaster and Emergency Services Director Ed Teague said it is possible to be submerged one hour under icy conditions and still be revived.

The incident recalls a similar accident in which Jimmy Tontlewicz, 4, fell into Lake Michigan in Chicago Jan. 15, 1984, while his father pulled his sled. Passers-by quickly rescued his father, but Jimmy stayed submerged for 20 minutes before divers pulled him from the cold water.

Doctors, who said Jimmy was legally dead when pulled from the lake, kept him in a drug-induced coma while they slowly raised his body temperature. Just a year later, doctors said Jimmy had made a remarkable recovery and his mother described him as a "normal little boy who's hyperactive."