The Visible Heart Lab has a research collaboration with Lifesource, a non-profit organ donation organization of the Upper Midwest. If an organ donor's heart is deemed not viable for transplant, our lab has the privilege to receive such a heart for research with the permission of the donor's family. If the heart is both primarily intact (including the presence of the great vessels) and is believed to elicit reasonable hemodynamic function, we will reanimate it on the Visible Heart Apparatus and obtain functional videos to share on this website. As with heart transplantations, we hope to have a given heart reanimated within 4-6 hours after recovery. Subsequently or if a given heart is not chosen to be reanimated, we will perfusion fix the heart to be preserved as an anatomical specimen. All such hearts are preserved in their end-diastolic state, which is the state when the heart is filled with blood before contraction. In other words, in this approach all four chambers are dilated simultaneously.