Chargers head coach Jim Harbaugh briefly left the team’s game against the Broncos during the first quarter on Sunday due to atrial flutter that he has dealt with for a number of years, he told reporters after the Los Angeles 23-16 win.

The Chargers had originally described it as an illness and he was ruled questionable to return at the time, before he ultimately came back to take over coaching duties again.

Defensive coordinator Jesse Minter took over as interim coach while Harbaugh in the locker room and deo from the CBS broadcast of the game showed Harbaugh make his way to the blue medical tent to be looked at before going back to the locker room.

“Everything turned out to be OK,” Harbaugh said. “It’s called atrial flutter and I got into an episode today with it. Doctors checked me out and it got back into Sinus rhythm, normal rhythm, so I came back.”

He added: “I could tell there was some irregular beats.”

He said he’s had previous episodes in 1999 and 2012, including one that happened during a “Monday Night Football” game.

He returned later in the first half to the sideline wearing a headset.

Harbaugh could be seen walking down the sideline before giving a thumbs up and then taking back the red challenge flag from one of his assistants.

The game had still been scoreless at the time of the issue when Harbaugh left the game. 

While the Chargers did not provide any specifics on the illness, it appeared to be serious enough to warrant his brother and fellow NFL coach to be pulled from his postgame news conference with reporters. 

John Harbaugh, the head coach of the Ravens, was pulled from the podium while he was talking with reporters so that he could be updated about his brother’s condition.

An atrial flutter is a type of arrhythmia that occurs in the upper chamber of the heart causing it to beat 250 to 350 times per minute.