Patrick Muldoon's Cause of Death Revealed

Patrick Muldoon's sudden death is being linked to more than just a heart attack ... newly released records show multiple serious medical conditions all collided at once.

The "Melrose Place" actor's death certificate, obtained by Us Weekly, lists his official cause of death as a heart attack, but it also reveals he was suffering from a hereditary coagulopathy disorder ... a genetic issue that disrupts the blood’s ability to clot ... as well as a pulmonary embolism ... a dangerous clot that can block blood flow to the lungs.

According to the Los Angeles County Department of Public Health, he was cremated on April 28.

We broke the story ... Muldoon was pronounced dead after his girlfriend, Miriam Rothbart found him unconscious in the shower on April 19. His last few Instagram posts showed no signs of distress ... instead showing him just living his life before his tragic passing.

Muldoon's ex, Denise Richards, shared a heartfelt tribute after his death, calling him her "best friend & family," while Tori Spelling remembered him as a "beautiful soul" with a quirky sense of humor.