What is the narrator's state of mind as the story opens?

Edgar Allan Poe's "The Pit and the Pendulum" is famously cited for its ability to evoke a sense of dread within the reader. One of the few tales of Poe's that actually has a relatively "happy" ending, this story centers around a man who is sentenced to a torturous death during the Spanish Inquisition.
At the beginning of the story, the narrator appears to be very delirious. He claims that he is "sick unto death with that long agony" and that his senses leave him as he is sentenced to die. This beginning is very impactful because it starts the story with immediate foreshadowing of the dark matter that is to come; the reader is immediately told of the conflict of the story. The narrator is sentenced to die, and that experience alone is enough to make any man mentally unstable. The narrator describes his state as "delirious horror" and cannot even hear the words that are spoken by the court that decides his fate. His state of panic foreshadows the desperation that he will possess later in the story when he is confronted with the torture chamber and the many efforts to destroy him.