The situational irony of this excerpt affects "The Tell-Tale Heart" most prominently in the response:
The narrator's frantic insistence that he is sane only helps to convince readers that he is not.
This response highlights the irony inherent in the narrator's claim to sanity, as his behavior and thoughts throughout the story reveal a disturbed mind. His attempts to assert his sanity only underscore his madness, which creates a tension between what he perceives and the reality of his actions. This contradiction is central to the story and enhances the sense of unease and suspense in Poe's narrative.