911 call reveals response to Bronny James' cardiac arrest: 'Get an ambulance here now'

LOS ANGELES -- The frantic call underscored the dire emergency:

"Listen ... listen to me," a distraught man tells a 911 operator. "Get an ambulance here now."

"All right, sir, we're going to send help," the operator responded. "Don't hang up, sir, don't hang up."

Bronny James, the 18-year-old son of Los Angeles Lakers legend LeBron James, had gone into cardiac arrest during basketball practice. The incoming freshman for USC's basketball team was hospitalized Monday, his family had said.

He has since been released from Cedars-Sinai Medical, the hospital said Thursday.

"Although his work-up will be ongoing, we are hopeful for his continued progress and are encouraged by his response, resilience, and his family and community support," said Dr. Merije Chukumerije, a cardiologist at Cedars-Sinai.

Chukumerije complimented the "swift and effective response" of the USC athletics medical staff.

"He arrived at Cedars-Sinai Medical Center fully conscious, neurologically intact and stable," Chukumerije said Thursday.

ABC News obtained the 911 call, and the Los Angeles Fire Department redacted a significant portion of the call, the agency said, in accordance with California public records disclosure laws.

The operator asks if there is "a doctor on scene" or a registered nurse and the caller says a doctor is not there.

Our sister station KABC in Los Angeles has not been able to independently verify if there was medical staff on the scene outside the caller's view.

Typically, an athletic trainer would be present at a collegiate practice. According to the NCAA, "All athletic trainers, team physicians and strength and conditioning coaches have received training/ certification in CPR and automated external defibrillator (AED) use."

On Thursday, LeBron James tweeted about his son for the first time since the practice incident, thanking well-wishers for sending his family "love and prayers."

"We feel you and I'm so grateful. Everyone doing great," the Lakers star wrote. "We have our family together, safe and healthy, and we feel your love. Will have more to say when we're ready but I wanted to tell everyone how much your support has meant to all of us! #JamesGang"

Cardiac arrest occurs when electrical disturbances cause the heart to suddenly stop beating. It may be fatal if not immediately treated but can be reversed by CPR and a defibrillator, according to the American Heart Association.

Bronny James, a 6-foot-3 combo guard, graduated this spring from Sierra Canyon High School in Chatsworth, where he averaged 14.1 points, 5.6 rebounds, 2.4 assists and 1.7 steals his senior year. He was rated a four-star recruit, and he stood out in the McDonald's All-American Game in March, featuring some of the country's top high school basketball players.

ABC News and the CNN Wire contributed to this report.