In Edgar Allan Poe's "The Tell-Tale Heart", we do see a variety of dark themes as are par for the course with Poe, but in particular we see guilt and the question of sanity.
Our narrator has this strange capacity throughout the text to hear a heartbeat. This seems to haunt him, but a greater label for the repeated disturbance would be guilt. Having killed someone close to him, he tells on himself but it is hard to identify what occurs as remorse, a feeling we would expect for such a crime so we have to turn to insanity.
My students often get lost in this piece wondering what different things mean or represent, but Poe is one of the most difficult authors to understand in terms of what might have been going on in his head. The narrator gives argument after argument to prove his sanity, but we audience members see these efforts as evidence of the insane because each one claims something normal persons just would not do.
Tell-tale heart is a story dominated by emotions(tension, anxiety, paranoia). The major themes are:
Madness/insanity: the narrator is insane he says"i loved the old man" but still he murders the old man just because he disapproved of his 'vulture eye'.The narrator says:"I made up my mind to take the life of the old man, and thus rid myself of the eye for ever." He keeps giving arguments to prove that he is sane but the reader sees these efforts as his mental hint.
Evil: A human being has perverse(vulgar), wicked side that can make him do evil things that have no apparent motive."Object there was none . Passion there was none . I loved the old man."
Appearance v/s Reality:
The evil within is worse than evil without. The old man has hideous, repulsive eye: outwardly, he is ugly on the other hand the narrator who seems innocent is inwardly ugly and repulsive as he plans to execute the murder.