Jim Harbaugh's heart scare at Empower Field surprised Justin Herbert

Jim Harbaugh didn't have the heart to tell Chargers quarterback Justin Herbert that he had left Sunday's game.

“He hid it really well because I didn’t know,” the Bolts quarterback said after Los Angeles defeated the Broncos 23-16 at Empower Field on Sunday. “They did a good job keeping calm and I hope he’s okay.”

With that, Herbert, who threw for 237 yards against a Broncos defense that lost Pro Bowl cornerback Pat Surtain II to a concussion in the first quarter, showed a look of genuine concern.

“Is he okay?” Herbert asked reporters in the visiting team’s press conference room.

“He’s fine,” a reporter replied.

“He's had it before…” another added.

Invite a second, concerned look.

“Yeah, I don’t know,” the quarterback said. “'Calm down. Let's sort this out.'”

Harbaugh, 60, left the visitors' sideline in the first quarter and was escorted to the Chargers' blue medical tent. Shortly afterward, the longtime coach was escorted to the Bolts' locker room, where he spent much of the first eight or nine minutes of the game. Defensive coordinator Jesse Minter officiated the game while Harbaugh was treated for a condition called atrial flutter, which causes the upper chambers of the heart to beat 250 to 350 times per minute.

The coach returned to the sideline later in the first quarter and finished the game without incident.

“Everything was fine,” Harbaugh later recalled. “The doctors examined me and it returned to sinus rhythm – the normal rhythm.”

Harbaugh said he underwent ablations for cardiac arrhythmias in 2012 and 1999 and that he noticed his heartbeat was abnormal during warmups before Sunday's game.

“I'm not good at taking my own pulse,” the coach continued, “so (a staff member) just took the pulse and it was in the arrhythmia range.” But I felt like we were good. And then they said, “No, we have to do an EKG.” So trust the doctors, you know? If you don’t trust your doctors, who are you going to trust?”

Harbaugh said he received an IV and Marco Zucconi, the team's director of player health, wellness and performance, “gave me some type of magnesium medication.”

Empower paramedics treated the Chargers coach in the locker room, checking his heart to make sure it was returning to sinus rhythm, the coach recalled.

“And I said, 'I'm fine,'” Harbaugh continued, “so I'm back out there on the field.”

While Harbaugh was being taken to the locker room, the Chargers had taken the ball away from the Broncos with a Bo Nix interception 1:23 into the game. The Bolts gained 39 yards on nine plays, but were stoned in the red zone when the Broncos defense forced a fourth-and-goal on 2nd down. Minter went for a 20-yard field goal, giving the visitors a quick 3-0 lead.

In November 2012, while coaching the 49ers, Harbaugh reportedly suffered a heart flutter on a Wednesday night during the week of preparation for a Monday night matchup against the Chicago Bears. Harbaugh missed a practice Thursday to undergo what he called “minor surgery,” but returned to work the next day. The Niners defeated the Bears 32-7.