If one is to retell the story from the point of view of the old man's heart, then one may wish to examine the passage in which Poe's narrator mentions that his thumb slips as he is about to open the lantern to look in on the old man (sixth paragraph):
...and the old man sprang up in bed, crying out, 'Who's there?' I kept quite still and said nothing. For a whole hour I did not move a muscle, and in the meantime I did not hear him lie down. He was still sitting up in the bed listening--just as I have done, night after night, hearkening to the death watches in the wall.
Presently I heard a slight groan, and I knew it was the groan of mortal terror. It was not a groan of pain or of grief. Oh, no! It was the low stifled sound that arises from the bottom of the soul when overcharged with awe. I knew the sound well. Many a night, just at midnight, when all the world slept, it has welled up from my own bosom, deepening, with its dreadful echo, the terrors that distracted me...
Poe's narrator goes on to explain that the "mournful influence of the unperceived shadow" causes the old man to "feel the presence of my head within the room."
It seems, therefore, if one is to change the point of view to the heart of the old man, that one may go from the perspective of feeling/sensing what the narrator is doing. For, Poe suggests that there is a duality to the narrator and his victim, does he not?