The death certificate specifies a heart attack, but I know of no heart ailment indicated by those symptoms.

7 seconds sound clip from the Revenge of the Zombies (1943) movie soundboard.

You can hear this line at 00:05:33.120 in the DVD version of the movie.

Quote context

[...]

- I met her only the day before, and she seemed well then.

- From what I can learn, the attack began with a feeling of drowsiness. In a few hours, she passed into a coma from which she never awakened.

- I made a determined effort to see her, but Dr. Von Altermann refused me permission.

- So what could I do? He was her attending physician, as well as her husband.

- Refused you? But you've known Lila all her life.

- The death certificate specifies a heart attack, but I know of no heart ailment indicated by those symptoms.

- They suggested something more sinister?

- They suggested poison.

- Finished, Master.

- It will do. Take it out.

- But what can we do now?

- See to it that your sister is buried immediately.

[...]