[The isolated rabbit heart: comparison between five different modifications].

Background: The isolated heart as an experimental model has been firmly established for more than 100 years.
Material and Methods: In this study, five modifications are compared: 1. modified Langendorff apparatus (LA) with modified Krebs-Henseleit (KH) solution a) not containing bovine serum albumin (BSA; n = 13) and b) containing BSA (n = 16), 2. LA with KH solution containing BSH and bovine erythrocytes (n = 14), 3. LA with support rabbit (n = 6), and 4. "working heart" preparation with KH solution, BSA and bovine erythrocytes (n = 16). In the latter modification, no balloon was inserted into the left ventricular cavity, i. e., systemic and coronary circuits were not separated from each other. After completion of the preparation and 20-min stabilization, hemodynamic and metabolic data were assessed while the hearts were contracting in the ejecting mode. Thereafter, protocols for different studies were performed that are not presented here. However, the stability of the modifications within their individual protocols is reported.
Results: The results suggest that hearts perfused with KH solution are well suited for short protocols. In spite of the additional costs and time, blood perfusion is required for long-lasting protocols or if changes in coronary flow are to be investigated.
Conclusions: The working heart exhibits both the best function and stability at a relatively low experimental expenditure. Yet, it is not suited for studies where perfusion pressure needs to be changed independent of arterial pressure.