In an exclusive clip of tonight’t new episode,Jack Osbourneseeks medical attention for an unusually high heart rate.
A pre-existing condition makes Osbourne’s situation more precarious.
Osbourne was diagnosed with the degenerative disease in 2012.

Jack Osbourne in ‘Special Forces: World’s Toughest Test’.Pete Dadds/FOX
“Your heart is getting almost twice as fast as what you normally run,” the doctor says.
“I think with your history, you’ve got to take it seriously.”
Special Forces: World’s Toughest Testairs Monday at 9 p.m. ET/PT on Fox.
Watch the exclusive clip from tonight’s new episode above.