Pressure volume curves in arrested heterotopic rat heart isografts: Role of improved myocardial protection

Background. To minimize decreases in left ventricular (LV) compliance immed iately after rat heart transplantation, we tested several different methods of myocardial protection. Materials and methods. Five groups of ACI rat hearts (n = 6 each) were arre sted by coronary perfusion with 5 ml of UW (University of Wisconsin), UW-BD M (UW with 2,3-butanedione monoxime), CU (Columbia University), or CU-BDM s olution or by LV injection of potassium chloride and Ringer's lactate immer sion (KCl/RL). After abdominal isografting and blood reperfusion for 15 min , transplanted hearts (TxH) were arrested and excised. Diastolic LV pressur e-volume curves (LVPVCs) were correlated with myocardial water content (MWC ). Native hearts (NH) were arrested identically to TxH and maintained at 4 degrees C by immersion. LVPVCs were measured at 15-min intervals for 40 min . Results. In three of four pressure intervals at Time 0, normalized LV volum e (LVV) was smaller (P < 0.05, ANOVA) in KCl/RL native hearts than in the f our perfusion groups. LW decreased significantly in NH after 45-75 min; LW decreased similarly with time in all groups. In TxH, postarrest LVVs were h igher with UW-BDM, CU-BDM, and CU than with UW or KCl/RL (P < 0.05, ANOVA). Expressing LW of TxH as a percentage of NH, UW-BDM, CU, and CU-EDM provide d qualitatively better diastolic properties than KCl/RL and UW. Conclusions. Thus rat LVPVCs can be improved after heart transplantation wi th alternative strategies of myocardial protection. KCl arrest decreases LV filling volume in this model and should be avoided. (C) 1999 Academic Pres s.