Let’s imagine that organs can be perfectly grown in a lab and installed into a body without any chance of rejection or other complications usually associated with organ transplant.
You, a perfectly healthy adult human, go to the doctor and have them put a second heart in your chest that is connected to the circulatory system with your original heart.
What would be the effects of this? Could it even be done in this hypothetical situation at all?
The proverbial “two hearts in one chest” indicate a split mind, and create much pain.
It won’t do no good. The two would work against each other.
Not only in the holistic meaning, also from a strictly materialistical / technical point of view, there is no way to make them work synchronized. It is the very nature of the heart to determine it’s own rhythm.
And even a singular heart can have some weirdness when it’s own timing signals find alternate paths, like in some arrythmias.
I can only imagine the chaos of trying to keep signals synchronized between two hearts.