Detection of left ventricular regional relaxation abnormalities and asynchrony in patients with hypertrophic cardiomyopathy with the use of tissue Doppler imaging

Background It is well known that the distribution and magnitude of left ventricular (LV) hypertrophy are not uniform in patients with hypertrophic cardiomyopathy (HCM), which results in regional heterogeneity of LV early diastolic function. The advent of tissue Doppler imaging (TDI) has allowed the noninvasive evaluation of regional IV wall motion velocities. The aim of this study was to evaluate regional LV relaxation abnormalities and asynchrony noninvasively in patients with HCM by using pulsed and color-coded TDI. Methods and Results We studied 20 patients with asymmetric septal hypertrophy (HCM group) and 18 age-matched normal patients (control group). The peak early diastolic motion velocity (Ew) and time From the aortic component of the second heart sound to the peak of the Ew (IIA-Ew) were measured by pulsed TDI. The myocardial velocity gradient during early diastole (MVG-Ew) also was measured by color-coded TDI. Mean values for these parameters were determined on the basis of measurements made at 2 sites of the ventricular septum or posterior wall at the levels of chordae tendineae and papillary muscles, The mean Ew and mean MVG-Ew for the ventricular septum and posterior wall were significantly lower, and mean IIA-Ew was significantly prolonged in the HCM group compared with the control group. This difference was most pronounced in the hypertrophied ventricular septum of the HCM group. The standard deviations of IIA-Ew For the ventricular septum and posterior wall were significantly greater in the HCM group than in the control group. The time constant of LV pressure decoy during isovolumic diastole (tau) correlated inversely with Ew and MVG-Ew and correlated directly with IIA-Ew. Furthermore, tau correlated directly with the standard deviation of the IIA-Ew. Conclusions LV early diastolic function in patients with HCM may be mediated by an augmentation of regional LV relaxation abnormalities and asynchrony.