Let's just use mine.

I'm holding my heart. It's blue. Not blue-body-part blue, but primary blue. I breathe. We breathe. "Why don't we just use my heart?" I inquire lightly. "I think that it would work — I'm healthy, I'm sure my heart is in great shape." I am unsure of who needs it, I've forgotten. Do I need put a heart back in me? Or can I give it to someone else? I inspect the heart, to see how hardy it is. How hearty. How robust. I'm not much surprised that it is blue — but, there seems to be far more fat and mineral build-up than I expected to find. That's what the light coloured stuff inside is, right? I expected it to be leaner, meaner. "I think it's still good —" I trail off while prodding the organ.

There appears to be plenty of room for blood to pass through.