Calcium-binding of cardiac sarcoplasmic reticulum and diastolic hemodynamics in volume overloaded XXXX hearts.

@entity308 @entity712 @entity1184 @entity1283 @entity235 @entity299 @entity141 @entity1284
The relationship between the active @entity141 -binding function of the cardiac sarcoplasmic reticulum (SR) and left ventricular (LV) relaxation was studied in various stages of chronically volume overloading @entity235 hearts induced by complete atrio-ventricular (A-V) block. Rapid kinetic measurement of the @entity141 -binding activity of SR was made using a dual-beam spectrophotometric assay procedure. LV hemodynamics, especially diastolic indexes, were evaluated by the pressure-volume relationship using a trans-epicardial echo-cardiographic technique. In this study the maximum @entity141 -binding capacity and the initial @entity141 -binding rate of SR were impaired in @entity1283 and failing hearts induced by @entity1284 . However, there was no significant difference of SR functional defect between the hypertrophied and the failing hearts. LV systolic properties were not influenced even by chronic @entity1284 . Its diastolic properties, however, were reduced with the progress of @entity1184 , and were estimated to respond more sensitively to the @entity299 compared with systolic properties. There was a close interrelation between the @entity141 -binding activity of SR on the molecular level and diastolic parameters, especially the time constant T, on the ventricular chamber level. In conclusion, the impairment of the @entity141 -binding activity of SR is a cause of @entity308 of LV diastole. However, the role of SR in the occurrence of @entity712 could not be clarified in this study.
