I don't have much call to hold body parts. I'm on the neuro/plastics team so I do mostly those fields. I have only been doing this since September of 2002, haven't done any hearts yet. I did have to hold a kidney the other day. The patient was getting new kidneys, and I had to hold one in place so the surgeon could see to sew the artery from the kidney to the artery in the patients body.
I have held things removed from the patient, such as spleen, gallbladder, appendix, intestine, brain tissue, tumor... Stuff like that, but not a lot of live parts still in the body.
Scott