The Young and the Restless star Kristoff St John died of heart disease, with heavy drinking at the time of his death a contributing factor. A coroner's report released on Tuesday lists "hypertrophic heart disease" as the cause of the 52-year-old's death on February 4 at his home in Los Angeles. "Hypertrophic" means the heart muscle has become abnormally thick. The report states that alcohol use along with a congenital artery problem contributed to St John's death. The report says that three days before his death, St John had been released from a mental health hospital where he had been admitted for alcohol abuse and threatening self-harm. St John played Neil Winters for 27 years on the CBS soap opera. He was nominated for 11 daytime Emmys, winning twice. Australian Associated Press