This is yet another one of those spicy details that Miley Cyrus has decided to share with the entire world in her book. She apparently suffers from tachycardia, which is an affection that makes her heart have a faster rate when resting than normal. Miley Cyrus wrote this about it in her autobiography: “The type of tachycardia I have isn’t dangerous. It won’t hurt me, but it does bother me. There is never a time onstage when I’m not thinking about my heart.” Ironically, by worrying about it, she is making it slightly worse because worrying does accelerate the heart a bit. I don’t know why Miley Cyrus just doesn’t consider herself to be a bit more “passionate” all of the time in comparison to other people and just leave it at that. But hey, then again, she does have to fill her book with something.