Preconditioning accelerates contracture and @entity855 depletion in blood-perfused XXXX hearts.

@entity35 @entity5649 @entity855 @entity63
We investigated the effect of preconditioning on the @entity63 -induced depletion of @entity855 in the blood-perfused @entity35 heart. Isolated hearts (n = 5/group) were aerobically perfused with whole blood from a support @entity35 and subjected to zero-flow global @entity63 (37 degrees C) for periods up to 35 min. Frozen hearts were taken for metabolic analysis. @entity63 contracture was assessed with an isovolumic intraventricular balloon. The study groups were 1) control (C) with unprotected @entity63 , 2) preconditioning (PC; 2 cycles of 3-min @entity63 /3-min reperfusion), and 3) cardioplegia (CP; St. Thomas') before @entity63 . Preconditioning accelerated, whereas cardioplegia delayed, @entity5649 (time to peak contracture: PC = 8.1 +/- 0.3 and CP = 25.1 +/- 0.2 min vs. C = 15.6 +/- 0.3 min, P < 0.05). The @entity63 -induced decline in @entity855 was delayed by cardioplegia but accelerated by preconditioning (P < 0.05). In a parallel study, preconditioning and cardioplegia protected postischemic contractile function to a similar extent. Thus, in the blood-perfused @entity35 heart, preconditioning accelerated @entity5649 and depletion of @entity855 . In contrast, cardioplegia slowed @entity5649 and @entity855 depletion.
