Rubinstein died Wednesday at Barlow Respiratory Hospital in Los Angeles, The Los Angeles Times reported. Rubinstein was hospitalized about two months ago after suffering a mild heart attack "She had ongoing health issues and unfortunately they finally overtook her," Stevens told the paper.
The Pittsburgh native made her film debut in the 1981 Chevy Chase film Under the Rainbow. A year later, the 4-foot-3 actress broke through in Poltergeist. In the horror film — and its two sequels — Rubinstein played a spiritual medium who comes to help push demonic forces out of a suburban family home.
Other notable roles included films such as Sixteen Candles, Teen Witch and Southland Tales. On the small screen, Rubinstein guest-starred on sitcoms like Caroline in the City and starred on the David E. Kelley drama Picket Fences in the mid '90s. She most recently made a cameo in the 2007 horror film Behind the Mask: The Rise of Leslie Vernon.
Beyond her acting career, Rubinstein was known for her activism. In 1985, she appeared in a series of Los Angeles-based TV and print ads directed toward gay men about promoting safe sex and AIDS awareness. Rubinstein also fought for little people looking to break into show business and formed the Michael Dunn Memorial Repertory Theater Company, named after the Oscar nominee of the same name. (Dunn made a splash on television as a recurring villain, Dr. Miguelito Loveless, on the 1960s series The Wild Wild West.)
Rubinstein has no immediate surviving family members.