A cause of death has been revealed for Iron Maiden alum Paul Di’Anno, who died last month at age 66.

At the time of Di’Anno’s death, his longtime label, Conquest Music, said he had been dealing with “several health issues” without offering further details. Representatives for Di’Anno said Monday they had since received permission from the singer’s family to reveal the results of his autopsy.

“His sisters Cheryl and Michelle confirmed the following: ‘Basically he had a tear in the sac around the heart and blood has filled inside it from the main aorta artery and that has caused the heart to stop,’ ” the Facebook statement said. “Paul’s death was instantaneous and hopefully painless. May he rest in peace.”

Accompanying the post was a photo of Di’Anno’s friends and family, who over the weekend hosted a show in his honor at the Underworld Camden, a live-music venue in London: “With a magnificent musical set, his musical colleagues said a worthy farewell to their friend.”

Di’Anno died Oct. 21 at his home in Salisbury, England. In the years leading up to his death, Di’Anno had been suffering from a weakened immune system after contracting sepsis nine years ago, his family and record label said in an Oct. 21 statement.

“Despite being troubled by severe health issues in recent years that restricted him to performing in a wheelchair, Paul continued to entertain his fans around the world, racking up well over 100 shows since 2023,” the statement said. “Conquest Music are proud to have had Paul Di’Anno in our artist family and ask his legion of fans to raise a glass in his memory.”

Later, Iron Maiden’s members and co-managers issued a statement saying they were “deeply saddened” by Di’Anno’s death.

“Paul’s contribution to Iron Maiden was immense and helped set us on the path we have been travelling as a band for almost five decades,” the band said. “His pioneering presence as a frontman and vocalist, both on stage and on our first two albums, will be very fondly remembered not just by us, but by fans around the world.”

Di’Anno was a member of Iron Maiden from 1978 to 1981. He recorded the band’s self-titled debut album in 1980 and then the 1981 follow-up, “Killers.” After he was fired, he was replaced by Bruce Dickinson, who has remained the act’s lead vocalist. Later, Di’Anno fronted other bands, including Killers, Battlezone and Warhorse.

In 2023, the singer revealed that Iron Maiden had helped him pay medical bills for treatment of a lung abscess, saying that he would be “forever grateful for that.”

Times staff writer Nardine Saad contributed to this report.