Significant dependency of left atrial strain on left ventricular longitudinal motion.

BACKGROUND: The effects of left ventricular longitudinal function on the left atrial strain, including the left atrial reservoir function, have not been adequately quantified. METHODS: A total of 124 patients who underwent echocardiography were enrolled in this study. Left atrial strain analysis was performed using two-dimensional speckle tracking echocardiography, and the left atrial volume was derived using the modified Simpson's method. The peak left atrial strain (LAS) and left atrial expansion index (LAEI), as indices of left atrial reservoir function, were measured. The global longitudinal strain (GLS) and mitral annular plane systolic excursion (MAPSE), which are indices of contractile motion toward the left ventricular apex, were also measured. The correlation between LAS and candidate determinants, including left ventricular systolic longitudinal function, was evaluated, and multivariate regression analysis was performed. RESULTS: A significant correlation was found between LAS and left ventricular systolic longitudinal functions, GLS (r = 0.63, p < 0.001), and MAPSE (r = 0.65, p < 0.001). Two models, which were selected by multiple regression analyses for LAS, included GLS or MAPSE as independent determinants. GLS and MAPSE were also the strongest predictors, among other factors. CONCLUSION: LAS, when determined by evaluating the left atrial reservoir function, was significantly associated with left ventricular function, especially the systolic longitudinal function. Left ventricular function should be considered when assessing left atrial function by LAS.

Importance of left ventricular contraction for left atrial reservoir function.

BACKGROUND: The determinants of left atrial (LA) reservoir function have not been clarified. METHODS: To elucidate the effect of left ventricular (LV) contraction on LA reservoir volume (ΔVLA), volume change due to mitral annular downward motion and aortic root anterior motion, which are related to LV contraction during systole, was calculated in 72 consecutive subjects [42 patients without any cardiac disease (control group), 13 patients with heart failure with reduced ejection fraction (HFrEF group) and 17 with preserved ejection fraction (HFpEF group)]. LA volume was calculated using the modified Simpson's method of bi-plane 2-D echocardiograms. ΔVLA was the difference between the maximum and minimum LA volumes. LA volume change according to mitral annular motion (ΔVMA) and aortic root motion (ΔVAR) were calculated by assuming an oval frustum and dented wedge, respectively. RESULTS: In the normal control group, ΔVAR + ΔVMA was 11.7 ml on average, correlating to ΔVLA (r = 0.55, p < 0.01), and the contribution rate to LA reservoir volume ((ΔVAR + ΔVMA)/ΔVLA) was 56% on average. In both, the HFrEF and HFpEF groups, ΔVAR, ΔVMA, and the contribution rate were significantly smaller than those in normal control group. Stroke volume correlated to ΔVAR and ΔVMA. The larger the maximum LA volume was, the smaller the contribution rate was. The smaller the rate was, the higher the systolic pulmonary artery pressure was. CONCLUSIONS: Both mitral annular motion and aortic root anterior motion, which are related to ventricular contraction, are important for the LA reservoir volume recruitment.

Normal values of real-time 3-dimensional echocardiographic parameters in a healthy Japanese population: the JAMP-3D Study.

BACKGROUND: The recently developed real-time 3-dimensional echocardiography (RT3DE) is a promising imaging method to quantify cardiac chamber volumes and their functions in clinical practice. However, normal reference values of RT3DE parameters have not been fully investigated in a large, healthy Japanese population. METHODS AND RESULTS: This study consisted of 410 healthy subjects aged from 20 to 69 years who had a RT3DE at one of the 23 collaborating institutions. All subjects had no history of cardiac disease and no risk factors. The mean values in men and women were as follows: 50 ± 12 ml/m(2) and 46 ± 9 ml/m(2) for left ventricular (LV) end-diastolic volume index, 19 ± 5 ml/m(2) and 17 ± 4 ml/m(2) for end-systolic volume index, 61 ± 4% and 63 ± 4% for ejection fraction, 64 ± 1 2 g/m(2) and 56 ± 11 g/m(2) for mass index, 23 ± 6 ml/m(2) and 24 ± 6 ml/m(2) for left atrial (LA) maximum volume index, 10 ± 3 ml/m(2) and 10 ± 3 ml/m(2) for minimum volume index, and 58 ± 6% and 58 ± 6% for percent volume change. LV sizes decreased with age, whereas LV mass index did not change. LA sizes slightly increased with age. CONCLUSIONS: This multicenter investigation determined normal reference values for LV and LA sizes, and their functional parameters on RT3DE in a large, healthy Japanese population. The results of the present study support the use of RT3DE for the diagnosis and management of cardiovascular disease.

Possible link between strain ST-T change on the electrocardiogram and subendocardial dysfunction assessed by two-dimensional speckle-tracking echocardiography.

AIMS: Strain ST-T changes on surface electrocardiogram (ECG) may reflect subendocardial dysfunction. We hypothesized that strain ST-T changes are associated with (i) decrease in longitudinal strain, (ii) decrease in early systolic clockwise twist and early diastolic untwisting, and (iii) augmentation of peak twist due to subendocardial dysfunction. METHODS AND RESULTS: Three levels of left ventricular (LV) short-axis views and three LV apical views were acquired in 46 hypertensive patients with LV hypertrophy and 23 age-matched control subjects using 2D echocardiography. Patients were divided into two groups according to the presence (n = 18) or absence (n = 28) of strain ST-T change on 12-lead ECG. Using 2D strain software, longitudinal, radial, and circumferential strain were measured. Early systolic clockwise twist, end-systolic twist, and untwisting at early diastole were measured from time-domain LV twist curves. No significant intergroup differences in LV ejection fraction were noted. Longitudinal strain was significantly reduced in hypertensive patients with strain ST-T changes compared with those without these changes or control subjects. Although LV twist at end-systole was similar between patients with and without strain ST-T changes, early systolic clockwise twist and untwisting was significantly reduced in strain ST-T change group compared with the no ST-T change group. Multivariate analysis revealed that not LV mass index but strain ST-T change was an independent predictor of global longitudinal strain. CONCLUSION: The reduction in longitudinal strain, early systolic clockwise twist, and untwisting in hypertensive patients with strain ST-T changes suggests possible link between this ECG abnormality and subendocardial dysfunction, which can be assessed by 2D speckle tracking echocardiography.

Subclinical left ventricular dysfunction in asymptomatic diabetic patients assessed by two-dimensional speckle tracking echocardiography: correlation with diabetic duration.

AIMS: Early detection of diabetic heart disease is important for the timely interventions resulting in the prevention for the future development of heart failure. Subclinical left ventricular (LV) systolic dysfunction may be identified by a reduction in longitudinal function, which can be assessed using 2D speckle tracking echocardiography (STE). METHODS AND RESULTS: To determine longitudinal, radial, and circumferential function, three LV short-axis and three LV apical views were acquired in 60 asymptomatic diabetic patients with normal LV ejection fraction (EF) and 25 age-matched healthy volunteers. Using 2D strain software, end-systolic longitudinal strain (LS), radial strain (RS), and circumferential strain (CS) were measured in 18 LV segments. No significant differences in LVEF were noted between two groups. Diabetic patients had more advanced diastolic dysfunction and increased LV mass compared with normal subjects. Basal, middle, and apical LSs were significantly lower in diabetic patients compared with control subjects, with 43% (26/60) of the diabetic patients showing abnormal global LS values (cut-off value: -17.2, mean - 2SD in control subjects). Basal RS and apical CS were also significantly lower in diabetic patients. Multivariate linear regression analysis showed that diabetic duration was the only independent confounder for the reduction of LS (t = 2.22, P = 0.0313). CONCLUSION: In addition to diastolic dysfunction, subclinical LV longitudinal dysfunction is preferentially and frequently observed in asymptomatic diabetes patients with normal LVEF. The decrease in LS correlated with duration of diabetes. 2DSTE has the potential for detecting subclinical LV systolic dysfunction and might provide useful information of the risk stratification in an asymptomatic diabetic population.

Effects of aging on left atrial function assessed by two-dimensional speckle tracking echocardiography.

BACKGROUND: Aging affects left atrial (LA) function, which can be assessed by two-dimensional (2D) speckle tracking echocardiography (STE). The aim of this study was to determine (1) the feasibility and accuracy of measuring LA volume with 2DSTE and (2) the effects of aging on LA function. METHODS: 2DSTE of the LA was acquired from the apical 4-chamber view (frame rate: 63 +/- 11 /sec, iE33) using prototype speckle tracking software (QLAB, Philips Medical Systems, Andover, MA) in 140 healthy volunteers (3-79 years, 74 men). LA wall was tracked on a frame-by-frame basis, and LA volume waveforms were generated. Maximum LA volume (LAVmax) and minimal LA volume (LAVmin), and the LA volume before atrial contraction (LAVpre-a) were measured. Passive emptying percent of total emptying (LA conduit function) and active emptying percent of total emptying (booster function) were calculated as ([LAVmax-LAVpre-a]/[LAVmax-LAVmin]) x 100 and ([LAVa-LAVmin]/[LAVmax-LAVmin]) x 100. RESULTS: Adequate LA volume waveforms were obtained in all subjects. A good correlation was obtained between speckle tracking-derived LA volume measurements and manually traced LA volume measurements of the identical 2D image (LAVmax: r = 0.93, P <.001, LAVmin: r = 0.88, P <.001, LAVpre-a: r = 0.92, P <.001). Passive and active emptying indices had a significant age dependency (r = 0.80, P <.001). Overall, passive emptying accounted for 67% of the total LA emptying ranging from 83% in the youngest to 42% in the oldest decade. CONCLUSION: Aging significantly affects LA conduit and booster function. 2DSTE can effectively and easily measure LA volume and has a potential for the noninvasive assessment of LA function.

Quantitative assessment of left ventricular volume and ejection fraction using two-dimensional speckle tracking echocardiography.

AIMS: Two-dimensional speckle tracking echocardiography (2DSTE) allows measurements of left ventricular (LV) volumes and LV ejection fraction (LVEF) without manual tracings. Our goal was to determine the accuracy of 2DSTE against real-time 3D echocardiography (RT3DE) and against cardiac magnetic resonance (CMR) imaging. METHODS AND RESULTS: In Protocol 1, 2DSTE data in the apical four-chamber view (iE33, Philips) and CMR images (Philips 1.5T scanner) were obtained in 20 patients. The 2DSTE data were analysed using custom software, which automatically performed speckle tracking analysis throughout the cardiac cycle. LV volume curves were generated using the single-plane Simpson's formula, from which end-diastolic volume (LVEDV), end-systolic volume (LVESV), and LVEF were calculated. In Protocol 2, the 2DSTE and RT3DE data were acquired in 181 subjects. RT3DE data sets were acquired, and LV volumes and LVEF were measured using QLab software (Philips). In Protocol 1, excellent correlations were noted between the methods for LVEDV (r=0.95), ESV (r=0.95), and LVEF (r=0.88). In Protocol 2, LV volume waveforms suitable for analysis were obtained from 2DSTE images in all subjects. The time required for analysis was <2 min per patient. Excellent correlations were noted between the methods for LVEDV (r=0.95), ESV (r=0.97), and LVEF (r=0.92). However, 2DSTE significantly underestimated LVEDV, resulting in a mean of 8% underestimation in LVEF. Intra- and inter-observer variabilities of 2DSTE were 7 and 9% in LV volume and 6 and 8% in LVEF, respectively. CONCLUSIONS: Two-dimensional speckle tracking echocardiography measurements resulted in a small but significant underestimation of LVEDV and EF compared with RT3DE. However, the accuracy, low intra- and inter-observer variabilities and speed of analysis make 2DSTE a potentially useful modality for LV functional assessment in the routine clinical setting.

Measurement of left ventricular mass by real-time three-dimensional echocardiography: validation against magnetic resonance and comparison with two-dimensional and m-mode measurements.

BACKGROUND: The recent development of 3-dimensional (3D) surface detection algorithm of the endocardial and epicardial surfaces from real-time 3D echocardiographic (RT3DE) datasets allows direct semiautomated quantification of left ventricular mass (LVM). Our aims were to (1) evaluate the accuracy of RT3DE measurements of LVM using this algorithm against cardiac magnetic resonance (CMR) reference and (2) compare RT3DE LVM with conventional M-mode, 2-dimensional (2D), and RT3DE-guided biplane measurements. METHODS: A total of 205 patients were studied in 2 protocols: (1) RT3DE and CMR imaging was performed on the same day in 55 subjects; (2) in an additional 150 subjects, RT3DE, 2D, and M-mode images were acquired. In both protocols, RT3DE endocardial and epicardial surfaces were semiautomatically identified at end diastole (QLab, Philips Medical Systems, Andover, MA) to calculate LVM. CMR, 2D, and M-mode-derived LVM were obtained using standard techniques. RESULTS: A significant correlation (r = 0.95) was noted between RT3DE and CMR-derived LVM with a small bias of -2 g. M-mode-derived LVM measurements (175 +/- 64 g) were significantly larger than RT3DE LVM (123 +/- 39 g, bias: 52 g) with moderate correlation (r = 0.76). No significant differences in LVM were noted between 2D (125 +/- 42 g) and RT3DE values (bias: 1.2 g) with good correlation (r = 0.91, P < .001). However, the best correlation was noted between RT3DE and RT3DE-guided biplane LVM values (r = 0.95, P < .001, bias: -4.6 g). Intraobserver, interobserver variability, and test-retest variability of the RT3DE measurements were 9%, 12%, and 6%, respectively. CONCLUSION: RT3DE imaging using the 3D surface detection algorithm allows accurate and reproducible measurements of LVM. RT3DE-guided biplane technique can be used as an accurate time-saving alternative in clinical practice.

Subclinical left ventricular longitudinal systolic dysfunction in hypertension with no evidence of heart failure.

BACKGROUND: The prevalence of subclinical left ventricular (LV) systolic dysfunction in asymptomatic hypertensive patients was determined using tissue Doppler imaging (TDI). METHODS AND RESULTS: TDI-derived mitral annular velocities were acquired in 35 control subjects, 92 asymptomatic hypertensive patients with no heart failure (HHD), and 15 patients with diastolic heart failure (DHF). No significant intergroup differences in LV ejection fraction were noted. Peak systolic annular velocity was significantly reduced in the DHF group compared with the control and HHD group. Using peak systolic velocity <6.1 cm/s as a cut-off value for abnormal velocity, 10% of HHD patients and 53% of DHF showed impaired LV longitudinal systolic velocity. Peak early diastolic annular velocities were significantly reduced in both the HHD and DHF groups compared with the control group. With multivariable regression analysis, peak early and late diastolic annular velocities, female gender and deceleration time of the E wave velocity were selected as independent predictors for peak systolic annular velocities. CONCLUSIONS: Systolic long-axis LV function was impaired in 10% of asymptomatic hypertensive patients. Its reduction was closely correlated with impaired diastolic function. Assessment of LV longitudinal function by TDI plays an important role in identifying diastolic dysfunction and subclinical LV systolic dysfunction in asymptomatic hypertensive patients.

Reduced and delayed untwisting of the left ventricle in patients with hypertension and left ventricular hypertrophy: a study using two-dimensional speckle tracking imaging.

AIMS: Newly developed two-dimensional ultrasound speckle tracking imaging allows measurements of left ventricular (LV) rotation and twist. Because LV untwisting predominantly occurs during the isovolumic relaxation period, its assessment reflects the process of LV relaxation. The aim of this study was to examine whether LV hypertrophy (LVH) adversely affects LV untwisting and abnormalities in LV untwisting could become a novel marker in assessing LV relaxation abnormalities. METHODS AND RESULTS: We acquired basal and apical LV short-axis images in 49 hypertensive patients. Using two-dimensional strain software, a time-domain speckle tracking was performed, and the mean value of LV rotation was obtained at each plane. LV twist was defined as apical rotation relative to the base. In order to adjust for inter-subject differences in heart rate, the time sequence was normalized to the percentage of systolic and diastolic duration. The degree of LV untwisting was calculated as the percentage of systolic twist : untwisting = (TwistES-Twistt/TwistES) x 100, where Twistt is twist at time t and TwistES is twist at end-systole. Although peak systolic twist was not different, early diastolic LV untwisting and untwisting rate during isovolumic relaxation period was significantly delayed and reduced in parallel to the severity of LVH, as assessed by LV mass index. CONCLUSION: The observed delayed and reduced diastolic untwisting during the isovolumic relaxation period noted in hypertensive patients with LVH may contribute towards the LV relaxation abnormality. Two-dimensional speckle tracking imaging is a novel tool which can be used for the non-invasive assessment of LV relaxation.

Assessment of left ventricular dyssynchrony with real-time 3-dimensional echocardiography: comparison with Doppler tissue imaging.

We studied the usefulness and reproducibility of real-time 3-dimensional (3D) echocardiography (RT3DE) for evaluating left ventricular (LV) dyssynchrony, and compared its results with Doppler tissue image (DTI) indices. Full-volume RT3DE data sets and 2-dimensional DTI from apical window were obtained in 122 participants. Using fast 3D border detection software, time to minimum systolic volume (Tmsv) was semiautomatically calculated in each region from a 17-segment model. Several dyssynchrony indices were then calculated: Tmsv-16SD, the SD of Tmsv in 16 of 17 segments, excluding the apical cap; Tmsv-12SD, the SD of Tmsv of 6 basal and 6 middle segments; and Tmsv-6SD, the SD of Tmsv of 6 basal segments. These dyssynchrony indices of RT3DE were then compared with two dyssynchrony indices measured by DTI: time to peak systolic velocity (TTPV)-12SD, the SD of time to peak systolic velocity of 12 LV segments; and time to cross over point of temporal axis (TTCO)-12SD, the SD of time to crossover point of temporal axis. RT3DE data was quantitatively analyzed in 117 of 122 patients. Tmsv-16SD (35 +/- 34 milliseconds) was significantly longer compared with Tmsv-12SD (27 +/- 30 milliseconds, P < .001) or Tmsv-6SD (23 +/- 28 milliseconds, P < .001). Tmsv-16SD increased significantly with the severity of LV systolic dysfunction. Fair correlation was noted among TTPV-12SD, TTCO-12SD, and Tmsv-16SD (r = 0.71, r = 0.73) and between Tmsv-16SD and LV ejection fraction (r = 0.80). Concordance rate between TTPV-12SD and Tmsv-16SD for detecting LV dyssynchrony was 79%. The corresponding value between TTCO-12SD and Tmsv-16SD was 80%. In conclusion, Tmsv-16SD correlated well with DTI-derived LV dyssynchrony indices. In addition to LV remodeling, fast border detection RT3DE provides useful parameters for evaluating LV dyssynchrony.

The mitral L wave: a marker of advanced diastolic dysfunction in patients with atrial fibrillation.

BACKGROUND: The prominent mid-diastolic filling wave (mitral L wave) indicates advanced diastolic dysfunction in patients in sinus rhythm. The aim of the present study was to determine the clinical implications of the mitral L wave in patients with atrial fibrillation (AF). METHODS AND RESULTS: Ninety-nine consecutive non-valvular chronic persistent AF patients were enrolled. The mitral L wave was defined as a distinct mid-diastolic flow velocity following the E wave with a peak velocity>20 cm/s. The prevalence of the L wave in AF patients (34/99, 34%) was significantly higher than that observed in patients in sinus rhythm during the same study period (23/946, 2.4%, p<0.001). Patients with AF and L wave were older, more frequently female and had a slower heart rate, shorter isovolumic relaxation times, larger E wave velocities and lower early diastolic mitral annulus velocity (E') resulting in the higher E/E' compared to those without L waves. The left atrial volume index was significantly larger in patients with an L wave. The Valsalva maneuver decreased, and leg elevation increased, the amplitude of the L wave in the subset of patients who received these procedures. CONCLUSIONS: The appearance of the mitral L wave in AF is relatively common, and its presence indicates advanced diastolic dysfunction, including elevated filling pressures and distended noncompliant LA.

Hypertrophic cardiomyopathy is associated with more severe left ventricular dyssynchrony than is hypertensive left ventricular hypertrophy.

OBJECTIVE: To evaluate left ventricular (LV) dyssynchrony in patients with left ventricular hypertrophy (LVH), and to compare abnormalities associated with hypertrophic cardiomyopathy (HCM) and hypertensive heart disease (HHD) using 2D speckle tracking imaging. METHODS: Basal, middle, and apical 2D LV short-axis images were acquired in 43 patients with LVH including 20 with HCM and 23 with HHD, and in 15 age-matched controls. Radial strain, circumferential strain, time interval from the R-wave to peak radial strain (Trs), and time to peak circumferential strain (Tcs) were measured in six equidistant segments at each level of the 3 LV short-axis views using 2D speckle tracking analysis. To assess LV dyssynchrony, Trs(cs)-18SD, the standard deviation (SD) of Trs(cs) in all 18 segments, was calculated. RESULTS: Regional radial strain in the middle and apical short-axis segments was significantly less in patients with HCM than in those with HHD. Regional circumferential strain in the apical short-axis segments was also less in HCM. Trs-18SD and Tcs-18SD were significantly longer in patients with HCM than in age-matched controls and patients with HHD (Trs-18SD: HCM: 88 +/- 32 ms, HHD: 51 +/- 20 ms, control: 45 +/- 12 ms P < 0.001, Tcs-18SD: HCM: 71 +/- 27 ms, HHD: 46 +/- 14 ms, control: 45 +/- 14 ms P < 0.001). CONCLUSIONS: The presence of LVH is thus not always associated with LV dyssynchrony. However, the greater reduction of regional strain and severe LV dyssynchrony in HCM may contribute to the adverse cardiovascular outcomes associated with this disease.

The assessment of left ventricular twist in anterior wall myocardial infarction using two-dimensional speckle tracking imaging.

BACKGROUND: Two-dimensional speckle tracking imaging allows noninvasive measurement of left ventricular (LV) strain, rotation, and displacement. We investigated whether LV twist would be depressed in anterior wall myocardial infarction (MI) as a result of reduced apical rotation. METHODS: Basal and apical LV short-axis images were acquired in 30 patients with anterior wall MI. Using commercially available 2-dimensional strain software, time domain speckle tracking was performed, and regional LV strain, rotation, and radial displacement were obtained in each plane. LV twist was defined as apical LV rotation relative to the base. Patients were divided into two groups according to global LV systolic function (normal LV ejection fraction [LVEF] group [LVEF > or = 45%, n = 16] and abnormal LVEF group [LVEF < 45%, n = 14]). RESULTS: Circumferential strain in the apex was significantly reduced in abnormal LVEF group compared with normal LVEF group (-7.3 +/- 2.6 vs -13.5 +/- 4.1, P < .001). Peak LV twist was significantly reduced in abnormal LVEF group (5.6 +/- 2.6 vs 9.8 +/- 4.0 degrees, P < .005) mainly because of reduced apical rotation. Peak positive and negative twist velocity was also significantly depressed (38.8 +/- 11.3 vs 52.1 +/- 19.3 degree/s, P < .05, and -42.6 +/- 17.8 vs -63.4 +/- 28.0 degree/s, P < .05, respectively). Significant correlation was noted between peak twist and LVEF (r = 0.73, P < .001) and LV end-systolic volume (r = 0.56, P < .001). The twist-displacement loop was markedly distorted in abnormal LVEF group. CONCLUSIONS: Systolic twist was decreased and diastolic untwisting was depressed in accordance with LV systolic dysfunction in anterior wall MI. These results suggest the significant impact of global LV systolic function on LV twist and twist-displacement loops in patients with anterior wall MI.

Age-related changes in left ventricular twist assessed by two-dimensional speckle-tracking imaging.

The aim of this study was to determine the normal value of left ventricular (LV) twist, and to examine the effects of aging on LV twist by newly developed 2-dimensional ultrasound speckle-tracking imaging. We acquired basal and apical LV short-axis second harmonic images in 118 healthy volunteers. Using commercially available 2-dimensional strain software, time-domain speckle tracking was performed, and mean value of LV rotation obtained at each plane. LV twist was defined as apical rotation relative to the base. Adequate data were obtained in 113 volunteers. During systole, the LV performs a wringing motion with a counterclockwise rotation at the apex and a clockwise rotation at the base. The mean value of peak twist was 7.7 +/- 3.5 degrees. Immediately after end systole, rapid untwisting develops. Different LV twist profiles are noted according to age. Peak LV twist was significantly higher, and the rate of LV untwisting significantly reduced and delayed, with advancing age. LV twist can be measured noninvasively by 2-dimensional ultrasound speckle-tracking imaging. The observed reduced and delayed diastolic untwisting with aging may contribute toward the tendency of diastolic dysfunction. This novel method allows the detailed study of diastolic function in various cardiovascular diseases.

Effect of aging on twist-displacement loop by 2-dimensional speckle tracking imaging.

BACKGROUND: Newly developed 2-dimensional (2D) speckle tracking imaging provides simultaneous information on both cardiac rotation and radial displacement throughout the cardiac cycle, thus, providing the opportunity to noninvasively construct twist-displacement loops. The aim of this study was to examine the effect of aging on twist-displacement loops. METHODS: Basal and apical 2D left ventricular (LV) short-axis images with high frame rates were acquired in 59 asymptomatic healthy volunteers. Using commercially available software, LV rotation and radial displacement were obtained at each plane by 2D speckle tracking analysis. LV twist was defined as apical LV rotation relative to the base. To adjust intersubject differences in heart rate, the time sequence was normalized to the percentage of systolic and diastolic duration. Volunteers were divided into 3 groups according to age. RESULTS: Twist-displacement loops were characterized by a figure of 8 configuration. There was a linear relation between twist and displacement during systole (r = 0.97), with its slope being significantly larger in the older group compared with the young group. During early diastole, a substantial degree of untwisting developed despite a relatively small reversal of systolic radial displacement, resulting in a much steeper twist-displacement relationship observed in all groups. Subsequent diastolic expansion occurred with more gradual additional untwisting. CONCLUSION: We found that 2D speckle tracking imaging successfully provides twist-displacement loop, noninvasively. Aging affects the systolic component of the twist-displacement loop. The assessment of twist-displacement loop may be useful for evaluating LV function.

Hypertension attenuates the efficacy of hypoglycemic therapy for preserving coronary flow reserve in patients with type 2 diabetes.

Impairment of coronary flow reserve (CFR) in patients with type 2 diabetes has been generally demonstrated; however, there have been few studies investigating CFR in cases of relatively well-controlled diabetes, in distinction to the influence of hypertension. The purpose of the present study was to evaluate the influence of diabetes and hypertension upon CFR in relatively well-controlled patients. This study included 12 healthy controls (C group) and 57 patients with type 2 diabetes (DM) and/or essential hypertension who were divided into three groups as follows: patients with DM (DM group; n = 24), patients with essential hypertension (HT group; n = 15), and patients with both DM and essential hypertension (DM+HT group; n = 18). We excluded patients with evidence of coronary artery disease and/or left ventricular hypertrophy. We performed transthoracic Doppler recording of diastolic coronary flow velocity (CFV) in the left anterior descending coronary artery at rest and after maximal vasodilation by adenosine infusion (140 microg/kg/min for 3 min) CFR was defined as the ratio of hyperemic to averaged basal peak CFV. The CFR (2.92 +/- 0.46) of the DM group was not decreased compared to that of the C group (2.96 +/- 0.58), although the CFR of the HT (2.33 +/- 0.25) and DM+HT (2.35 +/- 0.25) groups were significantly reduced. Left ventricular mass index, relative wall thickness, and diastolic function were worse in the HT and DM+HT groups than in the C and DM groups. Subjects with concentric left ventricular remodeling had a lower CFR than those with normal left ventricular geometry. In conclusion, adequate hyperglycemic control prevented the progression of coronary microcirculatory disturbance, but concomitant hypertension attenuated the effect.

Visualization of uveal perfusion by contrast-enhanced harmonic ultrasonography at a low mechanical index: a pilot animal study.

OBJECTIVE: To evaluate contrast-enhanced harmonic ultrasonography at a low mechanical index for its usefulness in visualizing uveal perfusion. METHODS: The study was performed with 9 rabbits, 6 intact and 3 with focal impaired blood flow in the uvea. Ultrasonography was performed by harmonic imaging (transmit, 5 MHz; receive, 10 MHz) with a contrast agent. The agent was administered at a dose of 50 microL/kg. Transmission power was at a mechanical index of 0.2, which is below the US Food and Drug Administration guideline. The images were compared between the impaired and intact eyes. For uveal measurements, video signal intensity-versus-time plots were generated in all cases. The plots were analyzed to obtain the rate of signal intensity increase and peak signal intensity. RESULTS: A clear increase of signal intensity was observed after contrast agent administration. The signal intensity of the uvea was lower in the impaired eye than in the intact eye. In the impaired eye, the intensity was lower on the side with impaired flow than on the other side. The differences were significant. CONCLUSIONS: Our findings suggest that uveal perfusion can be visualized by contrast-enhanced harmonic ultrasonography in the harmonic imaging mode at a low mechanical index.