Day 69: New.
You feel your own heart turning into something new and it is a strange thing. It still beats, and it still works, and you seem perfectly healthy, but something just isn't the same. Your skin tingles with a feeling of self-betrayal or invasion and you think, I must oust this newcomer! It's me against This, but it cannot be removed, it is in you and always has been.
That's the worst part. You feel your heart rattling about inside you, like a dried-up seed in a pod. You feel it seeking the right fit, the mold, the edges, and instead it keeps rattling and as it rattles, it changes. This transformation springs from something in the distant past and the distant future, ignited now only because of where you decided to go to dinner on Tuesday or who did or did not say hello to you at the meeting. The source is unclear. The reasoning is weak. But as your heart changes you also change, you begin to conform to it. After a time, you will be mostly ignorant of the way it felt before.