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?
But if the nodes are connected, it’s still a single pump.
You’re merely choosing to redefine the terms. The nodes are part of the heart as a system - remove the nodes and well, the pump no longer pumps.
Your argument is like saying you can split a multi-cylinder automotive engine in half, leave the ignition system in place, and you have 2 engines.
No, you have one engine split in two, with it’s electrical timing system still determining how each cylinder maintains the exact same timing as before.
(Automotive engines are essentially air pumps with very specific timining mechanisms, as each cylinder’s output affects other cylinders, akin to the timing in a heart).