THE CONTRACTION STATE OF MYOFIBRILS DURING GLOBAL-ISCHEMIA AND AFTER REPERFUSION FOLLOWING DIFFERENT FORMS OF CARDIAC-ARREST - CORRELATION WITH METABOLIC PARAMETERS IN THE CANINE HEART
A. Schmiedl et al., THE CONTRACTION STATE OF MYOFIBRILS DURING GLOBAL-ISCHEMIA AND AFTER REPERFUSION FOLLOWING DIFFERENT FORMS OF CARDIAC-ARREST - CORRELATION WITH METABOLIC PARAMETERS IN THE CANINE HEART, Pathology research and practice, 190(5), 1994, pp. 482-492
This study was undertaken in order to obtain information on the mode o
f reaction of the contractile apparatus after different forms of cardi
ac arrest, global ischemia and reperfusion, as well as on possible cor
relations between the contraction state of myofibrils and biochemical
parameters. During the survival time, before the level of 3 mumol/g(ww
) creatine phosphate (CP) is reached, the contraction state shows only
minor changes. During the revival time in which ATP tissue concentrat
ions decay to 4 mumol/g(ww), the contribution of ATP, lactate, anorgan
ic phosphate (Pa) and acidosis to the degree of relaxation depends on
the method of cardiac arrest. At defined biochemical values, the degre
e of relaxation is comparable after aortic cross clamping (ACC) and St
. Thomas perfusion, but significantly different compared to HTK perfus
ion. Thus, during the revival time, the relaxation of sarcomeres depen
ds predominantly on the composition of the solutions used for cardiac
arrest. The re-entry of contraction below 3 mumol/g(ww) ATP is correla
ted with the ATP concentration, independent of the form of cardiac arr
est. Reperfusion after HTK or St. Thomas cardioplegia and reversible i
schemia leads to the focal formation of contraction bands, which do no
t occur during ischemia. This contraction state is significantly more
pronounced after reperfusion of St. Thomas arrested hearts. Thus, the
contraction state of myofibrils is influenced not only by alterations
in metabolite concentrations, but also by the composition of cardiople
gic solutions and by the characteristic conditions (sufficient energy,
oxygen and Calcium) during reperfusion.