What technique does Poe use in the second paragraph of The Premature Burial to build suspense?

Poe is using a characteristic (for him) rhetorical move in which he says how bad it would be to do a certain thing then goes on to do exactly that thing. In this story, he talks about horrible tragedies that “no romanticist” should discuss in fiction -- the black hole of Calcutta, the Plague of London, etc. -- then goes on to write a story about an even more horrible tragedy – being buried alive. It is a kind of rhetorical foreshadowing.
In the second paragraph, Poe also makes another (for him) characteristic distinction between the kinds and degrees of horror certain events possess. Disasters in which many people are killed, he writes, are more diffuse in their terror than the singular even that happens to an individual. As he says, “I need not remind the reader that, from the long and weird catalogue of human miseries, I might have selected many individual instances more replete with essential suffering than any of these vast generalities of disaster.” Of course, this is exactly what he will do – the third paragraph introduces the idea of being buried alive. In each case, the effect is the same – to heighten expectations.