Assessment of age-related changes in left ventricular twist by 3-dimensional speckle-tracking echocardiography

OBJECTIVES

The purpose of this study was to determine the normal value of left ventricular (LV) twist in 3-dimensional (3D) geometry and to study the effects of aging on 3D LV twist by sophisticated newly developed 3D speckle-tracking echocardiographic techniques.

METHODS

Recent developments in miniaturized ultrasound arrays have provided us with high-quality 3D echocardiographic data. Speckle tracking based on 3D images is robust to out-of-plane motion error, whereas 2-dimensional speckle tracking is inherently unable to analyze 3D cardiac motion and may lead to measurement inaccuracies. Three-dimensional LV volumetric images were acquired from 124 healthy volunteers (aged 21-82 years) and were analyzed by a recent speckle-tracking method. Left ventricular twist was analyzed as apical rotation relative to the base in the 3D coordinates. The measured parameters in this study were peak apical rotation, peak basal rotation, peak LV twist, normalized peak LV twist, and peak untwist velocity.

RESULTS

As seen from the apex, the normal LV maintains a wringing systolic displacement with an initial counterclockwise rotation followed by a clockwise rotation in the LV basal plane and a counterclockwise rotation in the LV apical plane. In general, the apical and basal twist increases during the aging process, leading to an increased LV twist value. The mean peak twist ± SD in young participants (21-35 years) was 11.73° ± 2.67°, whereas the value for older participants (>65 years) was 18.57° ± 3.08° (P < .001).

CONCLUSIONS

Three-dimensional speckle-tracking echocardiography can be an effective noninvasive method for assessing 3D LV twist. Age-related differences in the 3D LV twist may be the result of the age-related changes in the endocardial myofibers.

Left ventricular dyssynchrony in patients showing diastolic dysfunction without overt symptoms of heart failure

BACKGROUND/AIMS

Few studies have assessed left ventricular (LV) dyssynchrony in cases of diastolic dysfunction that do not include overt symptoms of heart failure. We hypothesized that systolic or diastolic dyssynchrony involves unique features with respect to the degree of diastolic impairment in isolated diastolic dysfunction.

METHODS

We examined 105 subjects with no history of overt symptoms of heart failure and a left ventricular ejection fraction > 50% for mechanical dyssynchrony using tissue Doppler imaging.

RESULTS

In terms of longitudinal dyssynchrony, four cases showed (6.3%) LV intraventricular systolic dyssynchrony (SDS(LV)), whereas none had LV intraventricular diastolic dyssynchrony (DDS(LV)) or co-existing systolic dyssynchrony. Radial dyssynchrony (RD) was found in six cases (9.4%). After adjusting for age, SDS(LV) and DDS(LV) were found to be significantly related to increases in the E/E' ratio (r = 0.405 and p < 0.001 vs. r = 0.216 and p = 0.045, respectively). RD at the base and apex was also significantly related to increases in E/E' (r = 0.298 and p = 0.002 vs. r = 0.196 and p = 0.045, respectively).

CONCLUSIONS

Systolic and diastolic dyssynchrony in subjects with isolated diastolic dysfunction but without overt symptoms of heart failure was not as common as in patients with diastolic heart failure; however, the systolic and diastolic intraventricular time delay increased with increases in the E/E' ratio, an indicator of diastolic dysfunction.

Characteristics of myocardial deformation and rotation in subjects with diastolic dysfunction without diastolic heart failure

Background and Objectives

There have been very few pathophysiologic studies on isolated diastolic dysfunction. We hypothesized that the characteristics of isolated diastolic dysfunction would be located, on the clinical continuum, between those of a normal heart and diastolic heart failure.

Subjects and Methods

We enrolled 102 subjects who had no history of overt symptoms of heart failure and 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.

Results

The circumferential strains and radial strain at the apical level (RS_apex) were related to the ratio of the transmitral early peak velocity over the early diastolic mitral annulus velocity (E/E'). After adjustment for age, the RS_apex showed a positive relationship with the E/E' ratio; whereas, the circumferential strains did not. Instead, the circumferential strains demonstrated a significant correlation with age. Basal rotation and left ventricular (LV) torsion were also related to age, but had no relationship with the E/E' ratio. However, as the E/E' ratio value increased, systolic mitral annular velocity decreased.

Conclusion

Except for the RS_apex, LV myocardial deformation and rotation did not vary with the degree of E/E' ratio elevation when there was no associated diastolic heart failure. Additionally, in clinical situations such as isolated diastolic dysfunction, the advancement of age has a relatively greater influence on characteristics of LV myocardial deformation and rotation rather than on the E/E' ratio.