If they can print a structurally complete heart -- even one without a working SA node -- they would probably be able to print working replacement valves. That w

If they can print a structurally complete heart -- even one without a working SA node -- they would probably be able to print working replacement valves. That would be huge news. Animal replacement valves don't last forever. Nor do artificial ones. Having a working replacement grown/printed would be incredibly valuable for lots of people.