Heterogeneity of apex-to-base dispersion in diastolic lengthening is related to impaired global left ventricular relaxation in patients with hypertrophic cardiomyopathy.

BACKGROUND: The presence of apex-to-base disparity in diastolic left ventricle (LV) endocardial lengthening, based on an electromechanical activation sequence, has been recognized as an important determinant of LV diastolic properties. However, the behavior of LV apical and basal diastolic lengthening and its relationship to LV filling in hypertrophic cardiomyopathy (HCM) are unknown. METHODS: We obtained basal and apical LV short-axis views in 27 patients with non-obstructive HCM and 25 healthy volunteers. The patients with HCM were subdivided into two groups; those with apical hypertrophy [APH(+)] or those without apical hypertrophy [APH(-)]. Eight equiangular points on the endo-myocardium at end diastole were placed in each view, and the movements of these points were automatically tracked using a two-dimensional echocardiographic tissue tracking system. Time-LV internal diameter curves were obtained and averaged. The time intervals from the aortic valve closure to the point of the first 40% of peak diastolic lengthening (T 40) were measured in each view. The standard deviation of the time to peak systolic circumferential shortening at the base and apex were calculated to assess the heterogeneity of LV contraction. RESULTS: The time difference in the T 40 between the apex and base (dt-T 40) in the HCM-APH(+) and HCM-APH(-) groups was greater than that in the control group. The heterogeneities in LV apical systolic shortening in the HCM groups were greater than those in the control group. There were good linear correlations between the dt-T 40 and the LV early diastolic echo-parameters and the LV mass index. CONCLUSIONS: Delayed apical relaxation and filling in patients with HCM is related to LV diastolic dysfunction and systolic dyssynchronous contraction.

Ratio of early transmitral velocity to lateral mitral annular early diastolic velocity has the best correlation with wedge pressure following cardiac surgery.

BACKGROUND: Although previous investigators reported that mitral annular velocity predicts mean pulmonary capillary wedge pressure (PCWP), it is unknown whether the lateral or septal mitral annular velocity more faithfully predicts PCWP after cardiac surgery. METHODS AND RESULTS: To assess the effect of cardiac surgery on the predictive values for PCWP by measuring mitral annular velocity, 52 consecutive patients undergoing cardiac surgery were studied. All patients underwent transthoracic echocardiography and right-sided cardiac catheterization both before and after surgery. The peak early diastolic velocity of transmitral flow (E) was measured by pulsed-wave Doppler and the peak early diastolic velocities of the lateral (LEa) and septal (SEa) mitral annulus by pulsed-wave tissue Doppler imaging. The ratios of E to LEa (E/LEa) and SEa (E/SEa) were calculated. Immediately after echocardiography, PCWP was measured using a balloon-tipped pulmonary artery catheter. After surgery, LEa was significantly increased (6.4+/-2.7 vs 8.6+/-3.3 cm/s, p<0.001), but SEa was unchanged (6.0+/-2.5 vs 5.5+/-2.3 cm/s, p=0.09). E/LEa correlated well with PCWP both before and after surgery (r=0.79 and r=0.69, respectively, p<0.001). Although E/SEa correlated well before surgery (r=0.67, p<0.001), it correlated only weakly after surgery (r=0.44, p<0.01). CONCLUSIONS: E/LEa has the best correlation with PCWP both before and after cardiac surgery and may be more useful than E/SEa in the noninvasive estimation of PCWP.

Augmentation of left ventricular apical endocardial rotation with inotropic stimulation contributes to increased left ventricular torsion and radial strain in normal subjects: quantitative assessment utilizing a novel automated tissue tracking technique.

BACKGROUND: The difference in the left ventricular (LV) torsion of the endo- and epicardium (Endo, Epi) with inotropic stimulation and its relation to radial strain (RS) remain unclear. METHODS AND RESULTS: LV basal and apical short-axis images were recorded in 13 normal subjects at rest and during dobutamine infusion (5, 10 microg x kg (-1) x min(-1)). A total of 8 points (anterior, lateral, posterior and septum in both Endo and Epi) were manually placed by 2-dimensional tissue tracking technique and the movement of these points during a cardiac cycle was tracked, after which the rotation angles and RS were calculated. LV torsion was defined as the net difference between the basal and apical rotations. In the LV apex, Endo-rotation increased (7.8+/-2.7 to 14.1+/-4.6 degrees, p<0.01), whereas Epi-rotation was unchanged, with dobutamine. The apical Endo-rotation was significantly greater than the Epi-rotation, although no difference was seen between the Endo and Epi in the LV base throughout the study. During dobutamine infusion, the LV Endo-torsion increased (9.5+/-2.8 to 19.3+/-4.8 degrees, p<0.01) and these values were greater than those for Epi. The apical RS increased with the dobutamine dose (39.0+/-9.3 to 61.9+/-15.5%, p<0.01), whereas basal RS initially increased at 5 microg x kg(-1) x min(-1), but thereafter showed no further increase at 10 microg x kg(-1) x min(-1) of dobutamine. CONCLUSIONS: Augmentation of LV rotation with inotropism was clearly observed in the apical Endo, thus causing increased LV endo-torsion and apical RS.

Usefulness of mitral annular velocity in predicting exercise tolerance in patients with impaired left ventricular systolic function.

Left ventricular (LV) diastolic function is 1 of the determinants of exercise tolerance. However, the relation between early diastolic velocity of the mitral annulus (Ea) obtained by tissue Doppler imaging and exercise tolerance is unknown in patients with impaired LV systolic function. To investigate the feasibility of evaluating exercise tolerance using tissue Doppler imaging, we studied 53 consecutive patients (mean age 58 +/- 14 years) with a LV ejection fraction of <50% (mean 37 +/- 9%). We measured the peak early diastolic velocity of transmitral flow (E) and Ea at the lateral border of the mitral annulus and then calculated the E/Ea ratio. After echocardiography, we measured the peak oxygen consumption and anaerobic threshold (AT) by cardiopulmonary exercise testing. Of all the echocardiographic parameters, the best correlation for AT was the E/Ea ratio (r = -0.74, p <0.001). Peak oxygen consumption correlated well with Ea and the E/Ea ratio (r = 0.64 and r = -0.68, respectively, p <0.001). The AT and peak oxygen consumption did not correlate with conventional Doppler indexes. Using an AT of 8 ml/min/kg as the cutoff to separate severe exercise intolerance from normal, mild, or moderate exercise intolerance, a receiver-operating characteristic curve showed that an E/Ea ratio of >11.3 had the best combination of sensitivity (88%) and specificity (86%). Exercise tolerance correlated with the E/Ea ratio in patients with impaired LV systolic function. In conclusion, the evaluation of LV diastolic function using tissue Doppler imaging is useful for predicting exercise tolerance in patients with heart failure.

Aging and transmitral flow pattern in patients with systemic hypertension.

PURPOSE: Currently, the transmitral flow (TMF) pattern is routinely recorded as the first step in the assessment of left ventricular diastolic function. In young, healthy subjects, it is known that the early diastolic flow (E wave) of TMF is larger than the late diastolic flow (A wave). The E/A ratio then gradually decreases with age. This change in the pattern of TMF can be expected to occur earlier in patients with systemic hypertension than in healthy subjects. However, data pertaining to this matter are limited for Japanese patients. The purpose of this study was to investigate the changing pattern of TMF with age in Japanese patients with systemic hypertension. METHODS: A database of echocardiographic examination reports was surveyed. A total of 553 patients with systemic hypertension (HT group) and 394 patients without hypertension or organic heart disease (control group) were included in this study. The patients were subdivided according to age, after which the E/A ratio was compared for different patient categories and age groups. RESULTS: The E/A ratio gradually decreased with age in the control group, and the mean value of E/A was <1 in the sixth decade. On the other hand, the E/A ratio rapidly decreased and was <1 in the fifth decade in the HT group. CONCLUSION: In patients in the HT group, the E/A ratio decreased about a decade earlier compared with patients in the control group.