Left ventricular diastolic function of the reperfused postischemic donor heart.

This study examined the pathophysiological relationship between left ventricular diastolic function and myocardial biochemical changes during reperfusion following hypothermic cardioplegic preservation of the donor heart. Isolated canine hearts (n = 47) were preserved for 6 h at 5 degrees C, followed by normothermic reperfusion for 2 h. Regression analysis demonstrated a highly significant correlation between: Left ventricular maximum -dp/dt and the left ventricular end-diastolic pressure (r = -0.56, P = 0.001); myocardial concentrations of adenosine triphosphate (ATP) and Ca2+ (r = -0.59, P = 0.0001); maximum -dp/dt and myocardial concentrations of: (1) ATP, (2) Ca2+, and (3) total adenine nucleotide with left ventricular volume loading (r = -0.53, P = 0.003; r = 0.51, P = 0.002; and r = 0.52, P = 0.002, respectively); and left ventricular end-diastolic pressure and myocardial Ca2+ (r = 0.66, P = 0.0001). These results suggest that left ventricular relaxation, as assessed by maximum -dp/dt, has a negative correlation with left ventricular stiffness, as determined by the end-diastolic pressure in preserved donor hearts. Furthermore, increased myocardial Ca2+ concentrations reflect exhaustion of myocardial ATP. Thus, the myocardial Ca2+ concentration correlates directly with wall stiffness and inversely with ventricular relaxation, while ATP concentration correlates directly with ventricular relaxation.