I was honestly surprised how short this was, but that doesn't make it bad. Though I honestly am confused about (1) how people would even be able to tell she has this condition, and (2) why they would bully someone so terribly to the point of self-harm just because of a condition that literally has no symptoms 'nor disabilities. I don't mind short stories at all, they can normally be quite cute or powerful, but this one felt more like a detailed storyboard of an idea that the author had. That being said, I feel as though this idea would benefit more from a fully-fleshed out storyline, or even mini-series. But as it is now, it just kind of feels, unfinished I guess. Gotta respect the yuri part of it, and the heartbeat part was really cute.
I rated it a 6 out of 10 because I understood the emotion they were going for, and it's a cute idea, but it just didn't make me feel quite as satisfied as if it were a little longer of a story with more flesh and feeling to it.