What was the cause of death of actress Zena Walker?

I was curious when I read that her cause of death was undisclosed so I took the trouble to do an extensive web search and could find nothing. My curiousity was piqued because if a cause of death is undisclosed, it might be something embarrassing, which could give us some insight into the deceased's lifestyle.

However this appears to have been a decision by her family, possibly made to protect those left behind. If she killed herself, for example, they might want this kept private, and my feeling is that that ought to be respected.That's just one example of something that might be embarrassing, it could be a drug overdose, scihrrosis of the liver, or AIDS. Or something quite ordinary like a heart attack.

Of course her cause of death is a matter of public record and you can go to the registrar of Births Marriages and Deaths and obtain a copy of her Death Certificate. This will clearly state the cause of death.