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Background and Objectives: There have been very few pathophysiologic or clinical studies on isolated diastolic dysfunction (IDD) that does not present overt symptoms of heart failure. We hypothesized that the characteristics of IDD would be located between those of a normal heart and diastolic heart failure on the clinical continuum.Subjects and Methods: We enrolled 169 subjects (N=169) with no history of overt symptoms of heart failure who had a left ventricular ejection fraction of more than 50%; they were examined for myocardial deformation and rotation using the two-dimensional speckle tracking image (2D-STI) technique. According to the ratio of the transmitral early peak velocity over the early diastolic mitral annulus velocity (E/E' ratio), subjects were placed in the normal E/E' ratio group when the E/E' ratio was less than 9, in the elevated E/E' ratio group at greater than 15, and in the intermediate group between 9 and 15, respectively.Results: The changes of circumferential strains and radial strain of the apical level (RSapex) were related to the E/E' ratio. After adjustment for age, the RSapex showed a positive relationship with the E/E' ratio, whereas the circumferential strains no longer showed a relationship. Instead, the circumferential strains demonstrated a significant relationship with age. The basal rotation and left ventricular (LV) torsion were also related to age, but had no relationship with the E/E' ratio.Conclusion: In our study, the RSapex can be a possible surrogate marker for early detection of IDD among the various values of myocardial strain, furthermore independent with aging. The reason why RSapex is sensitive seems to be that the apical region is prone to the change of the end diastolic pressure and has a converging point during systole.