Study on the usefulness of precise and simple dynamic balance tests for the evaluation of recovery from intravenous sedation with midazolam and propofol.

BACKGROUND AND OBJECTIVE: Dynamic balance involving movement of the centre of gravity is important for the evaluation of street fitness after sedation. The purpose of this study was to compare the recovery of dynamic balance after intravenous sedation with propofol or midazolam, and to investigate the usefulness of simple dynamic balance tests in evaluating the recovery. METHODS: Fourteen young male volunteers underwent intravenous sedation with propofol and midazolam for 1 h each at an interval of more than 1 week. Computerized dynamic posturography using a multi-axial tilting platform, the 10-m maximum-speed walking test and the timed 'up & go' test (subjects stand up from a chair, walk 5 m and back with maximum speed and sit down again) were performed before and after sedation. The increase in each variable of the tests described above represents a reduction of function. RESULTS: The score of the computerized dynamic posturography was significantly lower in propofol sedation than that in midazolam sedation until 40 min after the end of sedation (P = 0.006). The scores of maximum-speed walking test and timed 'up & go' test were significantly lower in propofol sedation than those in midazolam sedation till 60 min after the end of sedation, respectively (P = 0.035 and 0.042). The timed 'up & go' and maximum-speed walking tests were well and significantly correlated with computerized dynamic posturography in midazolam sedation (timed 'up & go' test vs. computerized dynamic posturography: r = 0.66, P < 0.01; and maximum-speed walking test vs. computerized dynamic posturography: r = 0.53, P < 0.01). CONCLUSION: The timed 'up & go' and maximum-speed walking tests are useful simple dynamic balance tests well correlated with precise computerized dynamic posturography for the evaluation of the recovery of dynamic balance from midazolam sedation in younger adults.

Recovery of intentional dynamic balance function after intravenous sedation with midazolam in young and elderly subjects.

BACKGROUND AND OBJECTIVE: Computerized dynamic posturography using an intentional postural-sway task can be used to assess body-leaning ability and postural-control ability to prevent falls. Falls are the leading cause of morbidity and mortality for the elderly. The purpose of the present study was to evaluate the recovery of intentional dynamic balance function after intravenous sedation with midazolam in elderly subjects in comparison with that in young subjects. METHODS: Midazolam was administered in small, divided doses over 4-5 min until the Wilson sedation score reached three in 20 young and 18 elderly male volunteers. The dynamic limits of the stability test, in which subjects leaned their body intentionally as indicated by a cursor moving on a computer screen, was determined before (baseline) and 50, 70, 90, 110, and 130 min after administration of midazolam. RESULTS: The changes from baseline values of path sway and movement time 50 min after the administration of midazolam in elderly subjects (106.8 +/- 101.0%, 4.6 +/- 3.0 s; mean +/- SD) were significantly greater than those (32.9 +/- 87.2%, 1.9 +/- 2.8 s) in young subjects (P = 0.024, P = 0.008), respectively. CONCLUSIONS: The elderly show slower recovery of the intentional dynamic balance function than do young adults after intravenous sedation with midazolam.

Assessment of left ventricular systolic function using contrast two-dimensional echocardiography with a high-frequency transducer in the awake murine model of myocardial infarction.

The estimation of global left ventricular function using M-mode echocardiography has technical limitations in the murine model of myocardial infarction (MI), but the recent improvements in 2-dimensional (2-D) echocardiography using a high-frequency transducer provide more accessible images. Furthermore, intravenous injection of contrast agent has the additional benefit of enhancing the endocardial border in the murine heart. The present study was designed to evaluate the value of 2-D echocardiography with intravenous injection of contrast agent in the assessment of global systolic function of the murine heart with MI. Two-dimensional and M-mode echocardiography without and with intravenous injection of contrast agent (Optison, 0.1-0.15 ml) were performed in 76 awake mice 2 days before and 2 days after left coronary artery ligation. Fractional shortening (FS) was calculated from the end-diastolic and end-systolic diameters on M-mode echocardiography, and fractional area change (FAC) from the end-diastolic and end-systolic areas on 2-D echocardiography. Both FS and FAC were compared with the areas of hypoperfusion observed in the pathological samples. The use of contrast agent improved the number of hearts that could be evaluated by both the M-mode and 2-D method (M-mode: non-contrast 87% vs contrast 99%, p<0.01; 2-D: non-contrast 26% vs contrast 89%, p<0.001). FAC from the 2-D method correlated better with the region of hypoperfusion in the pathological samples than did FS from the M-mode method (FAC: r=0.84 vs FS: r=0.51). In conclusion, FAC obtained from 2-D contrast echocardiography is useful for noninvasive assessment of global systolic function in infarcted murine hearts and can be used to serially assess systolic function in various models of the murine heart.

LV volume quantification via spatiotemporal analysis of real-time 3-D echocardiography.

This paper presents a method of four-dimensional (4-D) (3-D + Time) space-frequency analysis for directional denoising and enhancement of real-time three-dimensional (RT3D) ultrasound and quantitative measures in diagnostic cardiac ultrasound. Expansion of echocardiographic volumes is performed with complex exponential wavelet-like basis functions called brushlets. These functions offer good localization in time and frequency and decompose a signal into distinct patterns of oriented harmonics, which are invariant to intensity and contrast range. Deformable-model segmentation is carried out on denoised data after thresholding of transform coefficients. This process attenuates speckle noise while preserving cardiac structure location. The superiority of 4-D over 3-D analysis for decorrelating additive white noise and multiplicative speckle noise on a 4-D phantom volume expanding in time is demonstrated. Quantitative validation, computed for contours and volumes, is performed on in vitro balloon phantoms. Clinical applications of this spaciotemporal analysis tool are reported for six patient cases providing measures of left ventricular volumes and ejection fraction.

Effect of neonatal capsaicin treatment on neural activity in the medullary dorsal horn of neonatal rats evoked by electrical stimulation to the trigeminal afferents: an optical, electrophysiological, and quantitative study.

To elucidate which glutamate receptors, NMDA or non-NMDA, have the main role in synaptic transmission via unmyelinated afferents in the trigeminal subnucleus caudalis (the medullary dorsal horn), and to examine the early functional effects of neonatal capsaicin treatment to the subnucleus caudalis, optical recording, field potential recording, and quantitative study using electron micrographs were employed. A medulla oblongata isolated from a rat 5--7 days old was sectioned horizontally 400-microm thick or parasagittally and stained with a voltage-sensitive dye, RH482 or RH795. Single-pulse stimulation with high intensity to the trigeminal afferents evoked optical responses mainly in the subnucleus caudalis. The optical signals were composed of two phases, a fast component followed by a long-lasting component. The spatiotemporal properties of the optical signals were well correlated to those of the field potentials recorded simultaneously. The fast component was eliminated by 6-cyano-7-nitro-quinoxaline-2,3-dione (CNQX; 10 microM), while the long-lasting component was not. The latter increased in amplitude under a condition of low Mg(2+) but was significantly reduced by DL-2-amino-5-phosphonovaleric acid (AP5; 30 microM). Neonatal capsaicin treatment also reduced the long-lasting component markedly. In addition, the decreases in the ratio of unmyelinated axons to myelinated axons and in the ratio of unmyelinated axons to Schwann cell subunits of trigeminal nerve roots both showed significant differences (P<0.05, Student's t-test) between the control group and the neonatal capsaicin treatment group. This line of evidence indirectly suggests that synaptic transmission via unmyelinated afferents in the subnucleus caudalis is mediated substantially by NMDA glutamate receptors and documented that neonatal capsaicin treatment induced a functional alteration of the neural transmission in the subnucleus caudalis as well as a morphological alteration of primary afferents within several days after the treatment.

Assessment of left ventricular function by real-time 3-dimensional echocardiography compared with conventional noninvasive methods.

Quantitative assessment of left ventricular ejection fraction is an essential component of cardiac evaluation. We performed real-time 3-dimensional echocardiography in 56 consecutive patients who underwent multigated radionuclide angiography. Thirteen patients were excluded for the following reasons: 5 for large size of left ventricle required for image acquisition, 5 for suboptimal image quality in real-time 3-dimensional echocardiography, and 3 for atrial fibrillation. Finally, we compared left ventricular ejection fraction assessed by real-time 3-dimensional echocardiography and conventional 2-dimensional echocardiography with that obtained by multigated radionuclide angiography in 43 patients. Left ventricular ejection fraction was determined by real-time 3-dimensional echocardiography with the use of parallel plane-disks and sector plane-disks summation methods. A good correlation was obtained between both real-time 3-dimensional echocardiography methods and multigated radionuclide angiography (r = 0.87 and 0.90, standard error of estimate = 3.7% and 4.2%), whereas the relation between the 2-dimensional echocardiography method and radionuclide angiography demonstrated a significant departure from the line of identity (P <.001). In addition, interobserver variability was significantly lower (P <.05) for the real-time 3-dimensional echocardiography methods than that by the 2-dimensional echocardiography method. Real-time 3-dimensional echocardiography may be used for quantification of left ventricular function as an alternative to conventional methods in patients with adequate image quality.

Neovascularization of ischemic myocardium by human bone-marrow-derived angioblasts prevents cardiomyocyte apoptosis, reduces remodeling and improves cardiac function.

Left ventricular remodeling is a major cause of progressive heart failure and death after myocardial infarction. Although neoangiogenesis within the infarcted tissue is an integral component of the remodeling process, the capillary network is unable to support the greater demands of the hypertrophied myocardium, resulting in progressive loss of viable tissue, infarct extension and fibrous replacement. Here we show that bone marrow from adult humans contains endothelial precursors with phenotypic and functional characteristics of embryonic hemangioblasts, and that these can be used to directly induce new blood vessel formation in the infarct-bed (vasculogenesis) and proliferation of preexisting vasculature (angiogenesis) after experimental myocardial infarction. The neoangiogenesis resulted in decreased apoptosis of hypertrophied myocytes in the peri-infarct region, long-term salvage and survival of viable myocardium, reduction in collagen deposition and sustained improvement in cardiac function. The use of cytokine-mobilized autologous human bone-marrow-derived angioblasts for revascularization of infarcted myocardium (alone or in conjunction with currently used therapies) has the potential to significantly reduce morbidity and mortality associated with left ventricular remodeling.

Anesthetic inhibition in ischemic and nonischemic murine heart: comparison with conscious echocardiographic approach.

It is well known that the level of anesthesia obtained by intraperitoneal injection is variable and may alter cardiac function. In this study, we compared the effects of different anesthetics on cardiac function with the conscious state using high-resolution two-dimensional echocardiography in nonischemic and ischemic mice. Eighty-four mice were tested before and after surgery with ligation of the coronary artery. All 84 mice were studied in the conscious state and under high-dose intraperitoneal anesthesia. Twenty-two of 84 mice were studied under low-dose intraperitoneal anesthesia. Another 22 mice were also studied under gas anesthesia and spontaneous breathing. Experiments in the conscious state were performed by two investigators before the administration of anesthesia: one investigator held the animal and the transducer and the other operated the ultrasound equipment. Left ventricular systolic function was measured, and measurements obtained after surgery were compared with infarcted areas assessed by histological staining. Results showed that both high- and low-dose intraperitoneal anesthesia significantly reduced heart rates and left ventricular contractility in both pre- and postsurgical mice as opposed to conscious mice (P < 0.01). There were significantly higher correlation coefficients between mean fractional area change (FAC) and infarcted area in conscious state compared with high-dose intraperitoneal anesthesia (P < 0.05). The correlation coefficient between FAC and infarcted area during gas anesthesia was also significantly higher compared with high-dose intraperitoneal anesthesia (P < 0.05). In conclusion, conscious experiments or the use of gas anesthesia is preferred for echocardiographic assessment of cardiac function in mice because intraperitoneal injection significantly induces a significant reduction in heart rate and left ventricular systolic function.

Assessment of segmental wall motion abnormalities using contrast two-dimensional echocardiography in awake mice.

Murine models of cardiac disease are becoming an important tool for studying pathophysiological processes. Development of methods to accurately assess ventricular function are therefore important. The purpose of this study was to evaluate the feasibility of echocardiographic assessment of segmental wall motion abnormalities in a murine model of myocardial infarction. Two-dimensional contrast (C+) and noncontrast (C-) echocardiography were performed in 76 awake mice 2 days before and 2 days after left coronary ligation. The short-axis images obtained with two-dimensional echocardiography and corresponding postmortem cross-sectional histological samples stained with Evans blue dye were each divided into 16 segments, and all matched segments were examined for correlation between wall motion abnormalities and myocardial hypoperfusion. With the use of contrast enhancement, the number of visualized segments was significantly increased (base: C- 86%, C+ 98%; midpapillary: C- 57%, C+ 89%; apex: C- 30%, C+ 74%). Agreement between echocardiographically assessed regional wall motion abnormalities and pathologically determined hypoperfusion in basal, midpapillary, and apical levels were 90%, 93%, and 93%, respectively. Agreement between echocardiographically normal wall motion and pathologically normal findings in basal, midpapillary, and apical levels were 99%, 88%, and 71%, respectively. Thus echocardiographic assessment of segmental wall motion in awake mice was feasible and the accuracy was improved with the use of a contrast agent.

Determination of left ventricular mass by real-time three-dimensional echocardiography: in vitro validation.

Twenty-one explanted fixed hearts (14 dogs and 7 pigs) were examined to validate newly developed real-time three-dimensional (RT3D) echocardiography for measurement of left ventricular (LV) mass in vitro and to compare its accuracy and variability with those of conventional echocardiographic measurements. There was an excellent correlation and high degree of agreement for the determination of LV mass between RT3D echocardiography and true mass measurement (r = 0.98; standard error of the estimate [SEE] = 7.3 g; absolute difference [AD] = 2.8 g; y = 1.00 x -4.0, interobserver variability; 5.0%). The conventional echocardiographic methods yielded weaker correlations, larger standard errors, and interobserver variability (area-length method: r = 0.90; SEE = 13.3 g; AD = 13.2 g; 13.3 % / truncated ellipsoid method: r = 0.91; SEE = 14.7 g; AD = 10.5 g; 7. 9% / M-mode: r = 0.91; SEE = 16.2 g; AD = 9.4 g; 15.3%). Determination of LV mass by RT3D echocardiography has a high degree of accuracy and is superior to conventional one- and two-dimensional echocardiographic methods.

Noninvasive assessment and necropsy validation of changes in left ventricular mass in ascending aortic banded mice.

Although left ventricular (LV) hypertrophy can be induced by aortic banding, noninvasive assessment of changes in LV mass in mice with a banded ascending aorta by using 2-dimensional (2D) images has not been previously performed. In this study we serially assessed changes in LV mass by 2D echocardiography with a newly available 12-MHz transducer in mice with a banded ascending aorta and validated measurements at necropsy. Estimated by echocardiography, LV mass increased from 74+/- 17 mg before banding to 191.08+/-54 mg at 8 weeks after banding (P <.0001), and excellent correlation was shown with postmortem measurements (r = 0.97). Furthermore, with the use of pulsed Doppler 2-dimensionally guided echocardiography, noninvasive measurement of flow velocities in the ascending aorta before and after the band at the various time points was possible. We propose that 2D echocardiography with a 12-MHz transducer is a powerful tool for serial noninvasive evaluations as an adjunct to the study of cardiac hypertrophy in the murine model.

Histological analysis of murine colitis induced by dextran sulfate sodium of different molecular weights.

In this study, we examined the relationship between the molecular weight of dextran sulfate sodium (DSS) and the features of colitis in a DSS-induced mouse model of human ulcerative colitis. DSS at three different molecular weights, 5 kD, 40 kD and 500 kD, was used in this study. DSS was administered in drinking water at 5% (w/v) to 6-7-week-old female BALB/c mice. After 7 days of treatment with DSS, the large intestine was examined histopathologically. Colitis was characterized by a loss of crypts, infiltration of inflammatory cells into the mucosa and submucosa, edema of the submucosa, erosion and ulceration and was observed in mice given the 5 kD and 40 kD forms but not the 500 kD. In the 5 kD group, colitis was observed predominantly in the cecum and upper colon. Colitis in the 40 kD group was more severe than that in the 5 kD group, and in the 40 kD group it was more severe in the lower colon than in the upper colon. These findings suggest the molecular weight of DSS to be an important factor in the murine model of colitis.

cAMP pulse during preservation inhibits the late development of cardiac isograft and allograft vasculopathy.

The causes of transplant-associated coronary artery disease remain obscure, and there is no known treatment. Preservation injury of murine heterotopic vascularized cardiac isografts caused a small, albeit significant, increase in neointimal formation; preservation injury of allografts markedly increased both the incidence and severity of transplant-associated coronary artery disease. As cAMP is an important vascular homeostatic mediator the levels of which decline during organ preservation, buttressing cAMP levels solely during initial preservation both improved acute allograft function and reduced the severity of transplant-associated coronary artery disease in grafts examined 2 months later. Inhibiting the cAMP-dependent protein kinase abrogated these beneficial effects. cAMP treatment was associated with an early reduction in leukocyte infiltration and a reciprocal decrease in superoxide and increase in NO levels. These data indicate that alloantigen-independent injury to the graft, which occurs at the time of cardiac preservation, can set in motion pathological vascular events that are manifest months later. Furthermore, a cAMP pulse during cardiac preservation reduces the incidence and severity of transplant-associated coronary artery disease.

Real-time three-dimensional stress echocardiography: a Review of current applications.

Cardiovascular stress testing plays a crucial role in the initial detection of coronary artery disease. In exercise stress echocardiography, the rapid acquisition of echocardiographic images is critical for accuracy. Real-time three-dimensional echocardiography permits the rapid acquisition of a volumetric data set that includes the entire left ventricle and allows the review of multiple, standard two-dimensional images from a single volumetric data set. Volumetric data can be obtained using both apical and parasternal windows. Often, satisfactory images are obtained in the majority of both prestress and poststress imaging using only an apical volume set. The following is a review of the current applications of real-time three-dimensional echocardiography in stress testing.

[Jichi Medical School Social Support Scale (JMS-SSS) revision and tests for validity and reliability].

OBJECTIVE: To develop a perceived social support scale for the Japanese. METHODS: Participants consisted of a total of 2,150 residents who responded to a perceived social support scale questionnaire in four communities involved in the Jichi Medical School Cohort Study at the study baseline in 1992-1994 (Analysis I) and 380 residents of Akaike town who responded to a questionnaire survey with the revised scale in 1999 (Analysis II). The first analysis was performed to confirm cross validity of the perceived social support scale measuring the availability of functional support from the spouse, family, and friends. The factor structures estimated for each district were compared with each other. The second analysis was set to revise the scale, modified in terms of a 4-point scoring format. The correlation between each item and a social desirability scale score, Cronbach alpha, and correlation coefficients between the revised scale scores and the original scale scores were calculated. RESULTS: Cross validity was confirmed based on the similarity of the factor structures of the responses obtained from the four different communities. Four selected indices supported the constancy of the factor structures across the communities. For the revised scale, two items were removed from the original scale-items measuring spousal support because of their statistically significant correlations with the social desirability scale score. The first principal component accounted for 57.0% of variance for spousal support, 68.2% for family support, and 67.0% for friends support and uni-dimensionality of the scales was confirmed. Alpha coefficients of the scales were .89, .95, and .94, respectively. Social support levels were stable over a mean period of 6.2 years. CONCLUSIONS: On an empirical basis, we have been able to develop a perceived social support scale. Homogeneous data from three different sources were obtained which were free from social desirability response bias and thus applicable for Japanese adults.

Changes in colonic mucosal permeability in mouse colitis induced with dextran sulfate sodium.

In this study we examined changes in colonic mucosal permeability induced by dextran sulfate sodium (DSS) during the acute phase of mouse colitis. To induce colitis, the mice were given drinking water containing 5% (w/v) DSS (MW = 40,000) ad libitum. Colonic mucosal permeability was evaluated by the permeation of Evans blue (EB) from the lumen into the wall of the colon on 1, 2, 3 and 7 days postadministration of DSS. Mucosal changes were also histologically examined daily for 7 days postadministration. The permeation of EB increased significantly by days 3 and 7 postadministration. Histological analysis showed that crypt loss was the initial change, with no inflammatory process and the surface mucosal epithelial cells remained morphologically intact. These histological changes developed on 2 to 3 days postadministration. Erosion was first recognized at 5 days postadministration. These findings indicated that the increase in colonic mucosal permeability may have occurred in 3 days postadministration, and the increase in mucosal permeability occurred before the appearance of the inflammatory process. This suggests that an increase in colonic mucosal permeability, leading to the destruction of mucosal barrier function, may play an important role in the induction of DSS-induced murine colitis.

Feasibility of real-time 3-dimensional treadmill stress echocardiography.

Rapid acquisition of echocardiographic images is critical for the predictive accuracy of stress echocardiography. Real-time 3-dimensional echocardiography (RT3D) allows review of several standard 2-dimensional images from a single volumetric data set. To assess the feasibility of RT3D for treadmill stress echocardiography, we performed treadmill stress RT3D on 20 volunteers (10 men and 10 women; mean age 32 +/- 6 years) with a device that uses a matrix phased-array transducer in a 60-degree pyramidal volume. Images are displayed as 2 steerable, intersecting B-scan sectors with adjustable C-scan planes parallel to the transducer face. At pre-exercise and immediate postexercise assessment, the volumetric data were obtained from apical and parasternal windows, respectively. Left ventricular segments were divided into 16 standard segments according to criteria defined by the American Society of Echocardiography. The use of both volume sets resulted in visualization of 98% of the segments at peak exercise. Even with only an apical volume set, 89% of the segments were adequately visualized. Image optimization and acquisition time at peak exercise was 35 +/- 18 seconds from the apical window and 50 +/- 28 seconds from the parasternal window. This preliminary study indicates that RT3D treadmill stress echocardiography is feasible and may be an important application of this new 3-dimensional device.

Lipoprotein(a) levels and apolipoprotein(a) isoforms related to life style risk factors.

Lipoprotein(a) [Lp(a)] has been considered to be a predictor of premature coronary heart disease and other cardiovascular diseases. Lp(a) levels are largely genetically determined, but the detailed mechanism of Lp(a) elevation is uncertain. We examined the association between Lp(a) levels and apolipoprotein(a) [apo(a)] phenotypes as well as that of Lp(a) level and other various conditions. The subjects were 280 healthy Japanese (102 males and 178 females) aged 39 to 70 years who were living in a rural community in 1992. We obtained apo(a) phenotypes determined by SDS-PAGE as well as Lp(a) levels and other cardiovascular risk factors. We combined apo(a) phenotypes form 4 groups according to molecular weights (from high apo(a) molecular weight to low: I, II, III and IV). Lp(a) levels were associated with apo(a) phenotype-groups, that is, they were inversely associated with apo(a) molecular weight. Small apo(a) phenotypes were less frequent than large ones. The median Lp(a) level was higher in smoking (29.2 mg/dL) than in non-smoking subjects (18.5 mg/dL) in phenotype-group III. Adjusted means of total cholesterol and fibrinogen levels in apo(a) phenotype-group IV were the highest of all phenotype-groups. Age, apo(a) phenotype, smoking status, total cholesterol and fibrinogen were positively correlated with Lp(a) levels by multiple regression analysis. Lp(a) levels were found to be mainly associated with apo(a) phenotype, but varied broadly within the same apo(a) phenotype at various conditions, such as smoking status and high total cholesterol.

Tissue distribution of dextran sulfate sodium (DSS) in the acute phase of murine DSS-induced colitis.

In the present study, we examined histochemically the tissue distribution of dextran sulfate sodium (DSS) in the acute phase of murine colitis induced by administering DSS in the drinking water. DSS was mainly observed in the Kupffer cells of the liver, in the macrophages of the mesenteric lymph node (MLN) and in the lamina propria of the large intestine after administration of DSS. We followed the time course of DSS distribution and found that DSS, which was considered as a large and negatively charged molecule that can not easily cross membranes, was distributed in the liver, the MLN, and the large intestine 1 day after the start of administration of DSS.

Real-time, 3-dimensional echocardiography acquires all standard 2-dimensional images from 2 volume sets: a clinical demonstration in 45 patients.

To test the hypothesis that real-time, 3-dimensional (3-D) echocardiography can obtain all standard 2-dimensional (2-D) views from acquisition of 2 volume sets, we scanned 45 patients (24 men, 21 women; mean age 49 +/- 17 years). This real-time 3-D device (VOLUMETRICS Medical Imaging, Durham, NC) uses a matrix phased array transducer in a 60 degree pyramidal volume. Images are displayed as 2 steerable, intersecting, conventional 2-D image sectors that can be oriented throughout 3-D space. By using this equipment, we were able to obtain 93.3% of standard views from a parasternal volume set and 85.2% of standard views from an apical volume set. The mean scanning time was 91 +/- 19 seconds for the parasternal volume set and 86 +/- 22 seconds for the apical volume set. We conclude that standard 2-D views can be obtained in the majority of patients by using this method. This equipment has the potential to substantially decrease the imaging time compared with the standard 2-D echocardiography.