In Vitro Studies of Human Hearts

Background Isolated mammalian hearts have been used in numerous studies that have led to many important discoveries in cardiac physiology, pharmacology, and surgery. Multiple methods of perfusion have been described including retrograde and/or antegrade flows and crystalloid or blood perfusates. Furthermore, multiple species have been utilized for such studies including the following: rat, rabbit, guinea pig, canine, and swine. The objective of this study was to describe a unique isolated heart preparation, utilizing human hearts not viable for transplant, which allows for physiologic perfusion and endocardial imaging. Methods Utilizing standard cardiac transplantation procedures, 12 human hearts deemed not viable for transplant were explanted to an isolated heart apparatus. A clear, modified Krebs-Henseleit buffer was used as a blood substitute, which allowed for endocardial imaging utilizing 6.0 mm endoscopic video cameras inserted into the cardiac chambers. The hearts were perfused in Langendorff (retrograde) and/or working (physiologic) mode. Results Eleven of 12 hearts achieved the following performance in working mode: peak left ventricular pressure of 21.5 to 75.8 mm Hg, with an average of 42.7 ± 19.9 mm Hg. Intracardiac anatomical imaging was possible in all hearts, providing unique views of normal and pathological endocardial anatomy as well as biomedical device-heart interactions. Conclusions We have described a unique isolated heart preparation with which we have successfully reanimated 11 human hearts deemed not viable for transplant, perfused them by working mode, and performed intracardiac anatomical imaging. This approach provides a novel means for obtaining images of functional human cardiac anatomy and various types of unique biomedical assessments.