Aims: Diastolic dysfunction (DD) identifies patients with increased cardiovascular risk. The aim of this study was to investigate the regional distribution of abnormal segmental relaxation in hypertensives with normal global DD and to demonstrate the incremental value of strain echocardiography over annular diastolic velocities and global indices of DD derived by conventional echocardiography.
Methods and results: We evaluated 70 individuals, consisting of 35 hypertensives and 35 middle-aged volunteers as a control. None had DD based on global indices (deceleration time, isovolumic relaxation time, and E/A). Segmental early and late diastolic Doppler-derived strain rates (SRs) were recorded from 18 segments in the longitudinal axis. The number of segments with SR(E)/SR(A)<1.1 was represented as segmental DD. Mean relaxation of the basal, mid, and apical regions was also calculated. Septal and mean mitral annular Ea velocities were also recorded. Non-hypertensive, middle-aged individuals had evidence of segmental DD that was mostly distributed at the basal parts of the heart, and in particular at the septal wall. Hypertensive patients had a lower mean relaxation based on SR(E) and SR(E/A) at the basal, mid, and apical regions, with the basal parts appearing more compromised and with higher segmental DD compared with controls. Segmental DD in that group was more extensive towards the mid and even apical regions, with the septal and basal inferior walls being the most heavily affected areas. The lateral wall appeared to be the region that was most resistant to diastolic abnormalities in both groups. Even individuals with 'normal' septal and mean Ea had evidence of segmental DD. However, contrary to global indices of DD, septal Ea could predict the presence of segmental DD.
Conclusion: Abnormal relaxation appears to have a particular distribution over the myocardial walls. Basal parts are generally more heavily affected, particularly the septal and inferior walls. The lateral wall and apical regions are more resistant to diastolic abnormalities. In subjects with normal global DD, strain echocardiography has an incremental value over mitral annular diastolic velocities and global indices of DD for early detection of diastolic abnormalities.