TikTok star Kyle Marisa Roth‘s cause of death has been revealed 4 months after her untimely passing shocked her followers … with her autopsy report ruling her death as “natural.”

In new documents obtained by TMZ … Maryland’s Chief Medical Examiner declared the internet personality died from cardiac arrhythmia due to myocardial fibrosis — which means she essentially had an irregular heartbeat caused by scarring on the heart muscle.

Her toxicology report found no signs of alcohol … but she did test positive for Diphenhydramine — a common antihistamine, marketed as Benadryl among other brand names — and Mitragynine … an alkaloid often used for pain management.

There had been quite a bit of speculation regarding Kyle’s death in recent months … especially after it was revealed her parents called in for a welfare check after seeing one troubling post on her TikTok account.

Kyle was best known for posting Hollywood blind items and showbiz gossip on the social media platform … but it’s unclear which specific upload sparked concern from her loved ones.

As TMZ previously reported … Annapolis PD made their way to Kyle’s apartment in April after her parents hadn’t heard from her in a while … where she was discovered deceased.

Kyle’s loved ones later confirmed her death on social media … with Kyle’s sister Lindsay telling fans the cause of death remained unclear — further fueling speculation about her passing.

Lindsay added at the time … “i know she touched so many people with her humor, intelligence, beauty, gossip activism, athleticism and more – she had so many gifts.”

Kyle was only 36.