Edgar Allan Poe's use of the devices mentioned above certainly do help to maintain interest in his short story, "The Tell-Tale Heart."
FIRST PERSON. Poe's use of first person narrative allows the reader to see inside the mind of the madman who kills and then dismembers his "friend." A third person narrative would show a far more detached feel with a less personal approach than through the protagonist's own eyes.
PUNCTUATION AND SENTENCE STYLES. Poe makes great use of the slash (or separatrix), especially in the opening paragraphs. It allows for a stop-start, choppy flow which seems to illustrate the mental instability and actions of the narrator. The constant use of the slash also allows for the narrator to include personal, exclamatory remarks within the sentence to further define the narrator's mood. Poe also uses an abundance of short sentences that give the story a hurried, almost desperate feel.