Heartworms

Heartworms

The Shins

Heartworms are parasitic worms that infect the host, generally a dog. They generally reside in the lung arteries, but in severe cases, they migrate to the pulmonary artery and the heart, eventually leading to death from congestive heart failure if left untreated.

Its name serves as an analogy for James' failing relationship and, presumably a woman, of her either imagined or real exploitative nature that is slowing killing him from the inside out, but he is paralyzed by fear and still intoxicated with her, thus in a way, he is letting her destroy him.