Bray Wyatt (whose biological name was Windham Rotunda), the WWE star who died last Thursday (Aug. 24) at the age of 36, passed of a heart attack, People reports.

According to TMZ, Wyatt had been suffering heart complications for months prior to his passing last week, and had been hospitalized a week before his death. Following his hospitalization, he had been advised by a doctor to wear a defibrillator, and was told to continue doing so during an appointment on Thursday.

However, he was not wearing the defibrillator when he was found “not breathing” and “turning blue” in his bed later on Thursday after going to take a nap by his fiance and ring announcer, JoJo Offerman. The outlet also reported that the defibrillator was located in his car, which was parked in the driveway. Offerman reportedly “became concerned when she heard his alarm going off about an hour later without stopping.” She called 911 as her mother attempted CPR.

Wyatt was pronounced dead at the hospital. He was believed to have a “weak lower part of his heart” following his contraction of COVID-19 in March.

Many have mourned the loss of Wyatt, including the WWE, which put together a 35-minute-long video of fellow WWE stars paying tribute to him and his career, including Drew McIntyre, who was awarded CBS Sports‘ “Wrestler of the Year” award in 2020. McIntyre said he “clicked with [Wyatt] right away.”

“The friendliest guy in the world, an amazing human,” he continued. “Such a brother.”

The tribute included WWE ring announcer and correspondent Samantha Irvin singing a beautiful rendition of “He’s Got The Whole World In His Hands.”

John Cena also took to X (the platform formerly known as Twitter) to honor Wyatt, writing that he was “devastated by the news of the passing of Windham Rotunda.”

“My heart goes out to the entire Rotunda family,” he added. “Windham brought the best out of me in so many ways. I’m forever grateful for the moments we shared. A sad day for all those he reached around the world. RIP.”