Deryck Whibley could feel his heart 'having a hard time' during hospitalisation

Deryck Whibley could feel his heart "having a hard time" when he was hospitalised with pneumonia in September.

The Sum 41 frontman developed a cold in September after coming off a tour but it spiralled into Covid-19 and then pneumonia.

In a profile interview with GQ, the Fat Lip rocker pinpointed the moment he became concerned about his welfare.

"When I got to the emergency room that night, they told me, 'You'll probably be here a few hours, you should be able to go home,'" he said, before revealing that he was transferred to another hospital to be monitored for potential heart failure.

"Up to that point, I was like, I've been through this s**t before, I'll be fine. But when the doctor was that concerned, that's what made it scariest for me. I could feel my heart having a hard time. I was struggling to breathe. My chest felt really tight."

The 43-year-old musician told his wife Ariana that he was "going to be really bummed" if he died because he had "so much cool s**t" lined up.

After a few days in the hospital, Whibley's heart stabilised and he was sent home to recover. Sum 41 was scheduled to play the When We Were Young festival in Las Vegas several weeks later and he was determined to perform so he got back in the gym as soon as possible.

"We got onstage and I felt f**king great," Whibley stated. "That was one of the best shows we've ever done."

Whibley was previously hospitalised in 2014 for severe liver and kidney damage caused by alcohol abuse.

Back in May, Sum 41 announced that they were to split up following a final run of live tour dates.