Although the Brothers spoke English, "Arthur Pim" was something not easily available in Soviet Union. Something known only to critics. AFAIK, only recently have they published that novelette by Poe in the collection of sc-fi stories together with the "Colder War" by Stross that studies deeply into Lovecraftian Kthulhu mythos. And Lovecraft, as we know builds on that Poe's novelette in narration of Antarctic horrors in his "At the Mountains of Madness".
So, I think it's a coincidence too. ^)