Why Chargers coach Jim Harbaugh briefly left Sunday's game

Los Angeles Chargers coach Jim Harbaugh left the sideline midway through the team's game on Sunday because of what he later said was “atrial flutter,” where his heart rate went out of rhythm.

Harbaugh, 60, visited the team's medical tent during the first quarter of the Chargers' 23-16 victory over the Denver Broncos. Chargers defensive coordinator Jesse Minter returned to practice after the first quarter after stepping down as interim head coach while Harbaugh was treated.

Harbaugh's brother, Baltimore Ravens coach John Harbaugh, abruptly left the team's postgame press conference after announcing that Jim had faced a health scare during the Chargers game.

Here's what you should know about Harbaugh's absence from the game.

What happened to Jim Harbaugh during the Chargers game?

The experienced coach Dr. Press conference after the game That he had a form of cardiac arrhythmia that he has had in the past. He told CBS sideline reporter AJ Ross the same thing during the game.

“Everything is fine,” he said at the press conference. “I treat it as, I think, a secondary (problem), it’s called atrial flutter. I got into an episode with this today. The doctors examined me and I was back in sinus rhythm, normal rhythm. So I'm back.”

An arrhythmia can cause the heart to beat too slowly, too fast, or irregularly. American Heart Association.

Premature beats may occur more frequently or have a rapid succession of causes “Vibrating” sensation Harbaugh said at the press conference. “Sinus rhythm” is a term used by Harbaugh to refer to the normal rhythm of the heart.

Harbaugh said he “noticed he had some irregular heartbeats during the game.” He said he was given intravenous fluids and an electrocardiogram test by the Chargers' athletic training staff.

“I know a lot about this, so I just wanted to see what the pulse was,” Harbaugh said. “I’m not good at taking my own pulse. So they just took the pulse and it was in arrhythmia. But I thought we were fine, and then they just said, 'No, we need to do an EKG.'

More sports from NBC News

“Trust the doctors,” he continued. “If you don’t want to trust your doctors, who are you going to trust? I always thought about that. And then I went back to the locker room and the paramedics came in and did an EKG. They said it was back to sinus rhythm and I said, 'I feel good.' So I went back to the field.”

Harbaugh returned to the sideline to coach for the rest of the game.

Does Jim Harbaugh have a history of heart problems?

The former San Francisco 49ers coach said he has had arrhythmia problems before.

“I left a few, one in 1999 and one in 2012,” he said. “And I will always remember the one from 2012 because it was during the Monday night game, Colin Kaepernick and the 49ers against the Chicago Bears, and Colin had a great night that night.

“After the game, I was examined and ended up having to have an ablation because he didn’t get back into rhythm.”

Harbaugh joked that after the 2012 49ers game and Sunday's game against the Broncos, he was “2-0 with an arrhythmia.”

Ablation is a procedure in which radiofrequency energy, such as microwave heat, destroys a part of the heart tissue that is causing the irregular heartbeat and helps restore the heart's normal rhythm, according to the AHA.

“I started feeling it last night,” Harbaugh said. “But I wasn’t really sure. But, yes, somewhere after the pregame warm-up. Just like in 2012. It was like during the warm-up before the game I started to feel it.

“And I haven’t felt that since 2012. That hasn’t happened. But in ’99, the procedure had to be done again after 13 years, so I figured I was getting close to the 13-year mark and would need another one at some point.”

John Harbaugh left the press conference after hearing about his brother

Jim Harbaugh said Chargers general manager Joe Hortiz contacted Jim's brother John and told him about Jim's situation. John then called his parents and told them the news.

The Baltimore Ravens' 30-23 victory over the Washington Commanders ended while the Chargers game was still being played. John Harbaugh was doing postgame commentary when he was informed that Jim had left the sideline.

John then suddenly left the press conference and made a call to check on his brother, according to Athletic.

The brothers are very close and have both been football coaches for a long time. They famously pitted against each other in the Super Bowl in 2013, when John's Ravens defeated Jim's 49ers in a 34-31 thriller.