The coroner’s report listed the star’s official cause of death as “hypertrophic heart disease” — a condition that thickens the heart muscle and can make it harder for the heart to pump blood, according to the Mayo Clinic.
The manner of death was determined to be an accident.
St. John, 52, was found dead at his home in the Woodland Hills neighborhood of Los Angeles on Sunday, Feb. 3, 2019.
Police were called to the scene after the actor’s friends went to check on him and found him unresponsive, officials said at the time.
The New York native was a daytime television favorite, having played Neil Winters on the CBS soap opera since 1991. Over the years, he won two Daytime Emmy Awards for his work on the series, according to his CBS biography. St. John also took home several NAACP Image Awards for the role.
Y&R paid tribute to the late actor days after he died, on its Feb. 8 episode. As Deadline previously reported, the show also plans to honor him with a special storyline in late April.
St. John had reportedly been struggling since the 2014 suicide of his 24-year-old son Julian, who died during a stay at a mental health hospital in Long Beach, California.