Edgar Allan Poe is known for his tales of suspense and macabre. Given that his works are embedded with dark images, mentally imbalanced characters, and Gothic settings, fear becomes a natural state of being in his works.
Poe is known as a Romantic writer. Romantics typically wrote about feelings and valued imagination. Poe was a master of both. Poe's works are filled with murders, violence, ghostly apparitions, and deformations. The mind of the reader should be filled with fear when reading Poe's works.
Not only should readers be filled with fear, many of the characters within Poe's texts exist in a fearful state. Fear of repercussion, hate, jealousy, and supernatural occurrences embody many of Poe's Gothic characters.
In the end, Poe wanted to elicit fear, and embed the fear, in his readers. He wanted them to live in the same state that his characters did: in a fearful state of being. (All figuratively of course.)