DENVER — After being briefly sidelined in the first quarter of Sunday’s win against the Denver Broncos, Los Angeles Chargers coach Jim Harbaugh told reporters that he had atrial flutter, a type of arrhythmia that causes the heart to beat abnormally fast prompted him to see a doctor.

Harbaugh went to the locker room, where paramedics treated him. He had an electrocardiogram and eventually they got his heart back into a normal rhythm. Harbaugh returned later in the first quarter and coached the rest of the game.

He said he’d had a bout of illness in a game before. He said that in 2012, while coaching the San Francisco 49ers in a game against the Chicago Bears on “Monday Night Football,” he felt an irregular heartbeat, but finished the game and then sought medical attention.

Doctors were unable to get Harbaugh’s heart back into a regular rhythm, so he underwent ablation, a procedure that uses heat or cold to destroy heart tissue that causes an irregular heartbeat. Harbaugh said he also underwent ablation in 1999.

“2-0 with a cardiac arrhythmia,” Harbaugh joked.

During his absence, defensive coordinator Jesse Minter served as interim coach, but many players didn’t even know that Harbaugh was absent during the game or that he had a heart problem.

Quarterback Justin Herbert found out when a reporter asked him about the situation during his postgame press conference.

“He’s tough,” Herbert said. “He did a really good job of hiding it because I didn’t know. You did a good job of staying calm. I hope he’s well. Is he okay?”

Harbaugh said he felt unwell Saturday night but didn’t think much of it. Then, during pregame warmups, he noticed his heart was beating irregularly and eventually alerted the coaching staff in the first quarter. He did not say whether he would undergo another ablation, but noted that the timing for the other ablations would be similar to now.

“I haven’t felt it since 2012,” Harbaugh said. “I mean, that hasn’t happened yet, but with the surgery in 1999, 13 years later, I had to have the procedure done again, so I thought I was getting close to the 13-year mark. I would need that.” one more at some point.

Harbaugh’s brother John, coach of the Baltimore Ravens, was in the middle of his press conference after the Ravens’ victory over the Washington Commanders but abruptly ended it to check on Jim. Chargers general manager Joe Hortiz reached out to John to tell him that doctors had cleared Jim and he was doing well.

The Chargers defeated the Broncos 23-16 and improved to 3-2.