Patrick Muldoon's cause of death at 57 has been ruled as a heart attack, with multiple underlying health factors also contributing.
Muldoon died as a result of a myocardial infarction, US Weekly reported Wednesday after reviewing the death certificate issued by County of Los Angeles’ Department of Public Health.
He had also dealt with a hereditary coagulopathy disorder, a condition that affects the blood's ability to clot, as well as a pulmonary embolism, a blood clot that could block vital arteries or one's lungs.
The actor, best known for his roles on Days of Our Lives and Melrose Place, was cremated on Tuesday, officials said.
Authorities listed Muldoon's occupation as an actor/producer in the certificate.
Muldoon suffered a heart attack at the Beverly Hills home he shared with his girlfriend Miriam Rothbart on April 19, his manager confirmed to Variety.
Patrick Muldoon's cause of death at 57 has been ruled as a heart attack, with multiple underlying health factors also contributing; Pictured in 2024
Muldoon died as a result of a myocardial infarction. He had also dealt with a hereditary coagulopathy disorder as well as a pulmonary embolism; Pictured with ex Denise Richards at the 2026 Saturn Awards in March, in what was his final public appearance
Muldoon's sister, Shana Muldoon-Zappa, told TMZ that Muldoon went to take a shower and was found unconscious on the bathroom floor when his girlfriend checked on him.
Paramedics tried to revive the star at home, but were unable to, officials said.
Muldoon, who was born in San Pedro, California, started his acting career while still in college at the University of Southern California with a two-episode arc on the sitcom Who's the Boss? with Tony Danza.
Shortly after graduating in 1991 he landed a three-episode recurring role on popular teen comedy Saved By The Bell.
His breakthrough role came when he landed the part of boxer Austin Reed on Days of Our Lives.
He appeared on the soap from 1992 to 1995 and later returning from 2011 to 2012.
He is also known for playing villain Richard Hart in Melrose Place from seasons three to five.
Muldoon's work on the big screen, for his role as Zander Barcalow in the 1997 sci-fi movie Starship Troopers, alongside his ex-girlfriend Denise Richards.
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His breakthrough role came when he landed the part of boxer Austin Reed on Days of Our Lives, appearing from 1992 to 1995; Pictured with Christie Clark as Carrie Brady in 1993
He is also known for his role as Zander Barcalow, left, in the 1997 sci-fi movie Starship Troopers, alongside his ex-girlfriend Denise Richards, right, and Casper Van Dien, center
Muldoon pictured at a Hollywood premiere in August 2012
Muldoon reunited with Richards to film his latest acting role in a crime thriller titled Dirty Hands, which will be released this year.
They had remained close friends after dating on-and-off for five years during the 1990s.
He appeared on an episode of The Real Housewives of Beverly Hills, when Richards was a cast member.
Muldoon had also been seen on her reality show Denise Richards & Her Wild Things, as they filmed a music video together.
Muldoon also dated Lisa Rinna, Tori Spelling and Juliette Binoche.
He had followed his passion for music and was the lead singer and guitarist for the rock band, The Sleeping Masses.
The star also worked as a producer, earning an executive producer credit in many films.
They included The Tribes of Palos Verdes, Arkansas, Marlowe, The Dreadful and most recently Kockroach, which is currently filming and stars Chris Hemsworth and Taron Egerton.
The actor, best known for his roles on Days of Our Lives and Melrose Place, was cremated on Tuesday: Seen March 8
He is also known for playing villain Richard Hart in Melrose Place from seasons three to five
Richards and the actor had remained close friends after dating on and off for five years during the 1990s
The actor's co-stars led tributes on Monday. Alison Sweeney who starred alongside Muldoon on Days Of Our Lives wrote on X: 'This is such heartbreaking news'
His Starship Troopers co-star Dina Meyer wrote: 'I can't believe he's gone. Pat was one of the kindest people I've ever known and was like a brother to me'
In his last Instagram post a day before his death, he wrote: 'So excited to be a part of this amazing project KOCKROACH directed by Matt Ross starring Chris Hemsworth, Taron Edgerton, Zazie Beetz And Alec Baldwin. Filming now in Australia.'
Fans flooded the post with tributes, with one writing: 'Grew up watching you in starship troopers. RIP legend.'
Muldoon made a final public appearance at the 2026 Saturn Awards in March, posing for photos alongside Richards.
Last year the actor teased a possible return to Days of Our Lives, appearing in a video shared on Peacock's official Instagram page.
In the brief clip, he could be seen wandering around the set of the daytime show before telling the cameras: 'Oh my God I'm in Salem! It's good to be back.'
The actor's co-stars led tributes on Monday: Alison Sweeney who starred alongside Muldoon on Days Of Our Lives wrote on X, 'This is such heartbreaking news. Pat was a rare kind of person – brilliantly talented, endlessly kind and generous in spirit.'
'I was so lucky to have worked with him when I first started at Days, he made me feel at ease right away. He brought his unique charm and humor to work every day. A truly gifted guy, and one who will be profoundly missed.'
His Starship Troopers co-star Dina Meyer wrote: 'I can't believe he's gone. Pat was one of the kindest people I've ever known and was like a brother to me. He was such a light... always making us laugh. My sincere condolences to his family, and everyone who loved him. He will be missed.'
Tori Spelling took to Instagram last week with a lengthy statement paying memorial to her former boyfriend; They are pictured in LA in 1995
Spelling last week took to Instagram with a lengthy statement paying memorial to her former boyfriend.
'This post took me a couple days,' Spelling said. 'I wasn’t ready to write because then it felt real. And, this shouldn’t be real.
The Beverly Hills, 90210 alum, 52, said they 'met on a blind date ... which thankfully wasn’t a blind date at all' since they were both on prominent TV shows at the time.
She continued, 'Like every other girl in the world I crushed on his character Austin from Days of Our Lives. Not sure I ever disclosed that to him.
'What I met and ultimately fell in love [with] was not just a beautiful on the outside creature but the most beautiful soul.'
Spelling called Muldoon 'special and one of a kind' and described him as 'kindest most caring human' who was 'passionate about everything he did.'
She added, 'He had a knack for making others smile & brought absolute joy to everyone that was blessed to be in his orbit.'
Spelling hailed Muldoon's talents as an actor and said he remained a true friend throughout the tough times she experienced, always providing support.
'I’m sorry to his family and the world for a beautiful light put out too soon,' she said.
Muldoon is survived by his partner Miriam Rothbart, and his parents Deanna and Patrick Muldoon Sr, as well as his sister Shana and brother-in-law Ahmet Zappa, and their children Halo and Arrow Zappa.