Determination of left ventricular mass by transthoracic three-dimensional echocardiography in patients with dilated cardiomyopathy

Conventional echocardiographic methods of measuring left ventricular mass (LVM) are limited by assumptions of ventricular geometry and image plane positioning. Three-dimensional (3D) echocardiography offers a promising new approach for more accurate determination of LVM. This study was performed to compare LVM measurement by one- (1D), two- (2D), and 3D echocardiography with magnetic resonance imaging (MRI) in patients (pts) with dilated cardiomyopathy (DCM). 36 pts (age 18-74) with DCM underwent imaging by conventional 1D and 2D echocardiography as well as transthoracic 3D echocardiographic data acquisition. Also, pts were imaged with cardiac MRI. Due to echocardiographic and MRI quality and because of exclusion criteria's for MRI, it was not possible to accomplish each LVM determination method for each patient. LVM was determined by Devereux and area-length algorithm for the conventional echocardiography. 3D echocardiographic data was calculated after manual delineation of endo- and epicardial boundaries--slice by slice (5 mm)--in 3 perpendicular cut planes. LVM was determined by multiplying the myocardial volume by the specific density of the myocardium. To determine LVM in MRI, the even summation of slices method for myocardial volume measurement was used defined by the endo- and epicardium in short axis images. There was no significant correlation (r = 0.42) for measuring LVM between 1D echocardiography and MRI in pts with DCM. A significant correlation was obtained between 2D (r = 0.64, p < 0.01) echocardiography and MRI as well between 3D (r = 0.78, p < 0.01) and MRI in determination of LVM. Compared with 1D and 2D echocardiography, the 3D analysis achieved a significantly higher agreement with the results of the MRI (1D: 399.2 g, 2D: 285.9 g, 3D: 172.6 g versus MRI: 199.1 g). Interobserver variability was 5.1% for measuring LVM by 3D echocardiography (1D: 11.2%, 2D: 9.1%). In conclusion, in pts with DCM the determination of LVM was incompletely characterized by 1D and 2D echocardiography compared with results of MRI. The best correlation and high agreement for determination of LVM was obtained with 3D echocardiography compared with MRI.     

Inappropriate left ventricular mass in normotensive and hypertensive patients

We evaluated cardiovascular features of normotensive and hypertensive adults with left ventricular (LV) mass values exceeding levels predicted for given stroke work, gender, and height, termed "inappropriate" LV mass. Inappropriate LV mass is associated with overweight, concentric LV geometry, and low myocardial systolic function not only in hypertensive subjects, but also in normotensive subjects.     

Early alterations in left ventricular diastolic function in normotensive diabetic patients

In diabetes mellitus, structural and functional alterations of the heart can be already present at the time of first diagnosis. However, how early these alterations may occur has never been fully clarified. The present study aimed at investigating cardiac functional abnormalities in uncomplicated hypertensive or normotensive patients with a recent diagnosis of diabetes mellitus. We studied 40 diabetics (24 normotensives and 16 hypertensives) by means of routine echocardiography plus pulse tissue Doppler analysis. Data were compared with those obtained in healthy age- and sex-matched controls. Left ventricular remodelling was more evident in hypertensive diabetics than in normotensive diabetics vs controls. Diastolic function was altered in diabetic patients only when detected by pulse tissue Doppler analysis and not by conventional transmitral Doppler evaluation. Normotensive patients with type 2 diabetes with little or no evidence at standard echocardiography of alterations in cardiac structure and function, already displayed an alteration in diastolic function when the evaluation was based on the tissue Doppler approach. Patients with type 2 diabetes combined to hypertension showed more evident functional cardiac alterations at echocardiography. These findings support the conclusion that cardiac abnormalities are very early phenomena in type 2 diabetes.     

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.     

Canine left ventricular mass estimation by two-dimensional echocardiography

This study was designed to develop a two-dimensional echocardiographic method of measuring the mass of the left ventricle. The general formula for an ellipse was used to derive an algorithm that described the shell volume of concentric truncated ellipsoids. In 10 canine left ventricular two-dimensional echocardiograms, this algorithm accurately predicted postmortem left ventricular mass (r = .98, SEE +/- 6 g) and was independent of cardiac cycle phase (systole vs diastole, r = .92).     

Troglitazone, an antidiabetic drug, improves left ventricular mass and diastolic function in normotensive diabetic patients

AIMS: Patients with NIDDM have excessive cardiovascular morbidity and mortality, even in the absence of hypertension. Left ventricular hypertrophy (LVH), which is an ominous prognostic sign and an independent risk factor for cardiac events, is often present in NIDDM patients. METHODS AND RESULTS: NIDDM male patients with (n=10) and without (n=12) hypertension, all of whom had been diagnosed over 10 years ago, were examined in the present study. Normotensive NIDDM patients had not received any anti-hypertensive drugs. All patients were classified according to the left ventricular mass (LVM) index by using M-mode echocardiography and were assessed regarding their systolic (fractional shortening) and diastolic function, which included the maximal early flow velocity (MFV), the mitral valve deceleration time (DT), and the isovolumic relaxation time (IRT) as determined by Doppler indices. Troglitazone (TRO), an antidiabetic drug, was administered to both groups at a dose of 400 mg/day for 6 months. After TRO treatment, a reduction in the LVM index and an improvement in the diastolic function were observed in the normotensive but not in the hypertensive patients. CONCLUSION: The TRO treatment was sensitive for cardiac regression in those normotensive patients. These results suggest that LVH and the diastolic function in NIDDM patients without hypertension may be associated with elevated insulin resistance because TRO has a pharmacological function to increase the insulin sensitivity and to decrease insulin resistance.     

Evaluation of left ventricular mass by M-mode and bidimensional echocardiography

The aim of this study was to validate an echocardiographic method of evaluating LV mass by assessing the reproducibility and comparing the results with those of angiography. 20 patients without abnormal regional wall motions or asymmetric septal hypertrophy underwent left ventriculography in the RAO plane and three successive M mode and 2D echocardiograms. Three 2D echo methods of measuring volumes and mass were used: the monoplane ellipsoid model obtained from apical views, the biplane ellipsoid model from an apical and a short axis parasternal view and the hemi-ellipsoid-cylinder model (HEC). The M mode evaluations showed good reproducibility with respect to volume (variation coefficient (VC): inter observer 9.8 p. 100 and intra patient 15.6 p. 100). The reproducibility of 2D echo measurements was much poorer (intra patient volume: VC = 34 to 45 p. 100; mass 29 to 46 p. 100). A close correlation was observed between the results of M mode echo and angiography; volume r = 0.85, SD = 60 g. With respect to the 2D method, the best results were obtained with the HEC model; volume r = 0.90, SD = 31 ml; mass r = 0.82, SD = 41 g. We suggest a method combining the M mode and 2D techniques, using a HEC model in which the long axis is obtained by 2D echocardiography and the short axis and wall thickness by M mode recordings. The following correlations with the angiographic method were obtained: volume r = 0.91, SD = 36 ml; mass r = 0.89, SD = 27 g.(ABSTRACT TRUNCATED AT 250 WORDS)     

M-mode echocardiography overestimates left ventricular mass in patients with normal left ventricular shape: a comparative study using three-dimensional echocardiography.

AIMS: We sought to evaluate whether left ventricular (LV) mass (M) determined by M-mode echocardiography is overestimated compared with LVM calculated by three-dimensional (3D) echocardiography (E) in patients with normal LV shape. METHODS AND RESULTS: A total of 112 studies in 56 patients (60+/-13 years) with hypertension (n=25) or aortic stenosis (n=31) and 30 control subjects (57+/-14 years) evaluated for cardiac sources of embolism were analyzed. LVM by M-mode and 3DE was highly correlated (r=0.85; p<0.001). However, there were broad limits of agreement (-58 to 110 g) demonstrating large variability between the methods. M-mode overestimated 3DE LVM by a mean of 15+/-24% (p<0.001) with overestimation in controls and the different patient groups. Variability was unrelated to increasing quartiles of LVM values. Using technique-specific partition values for normal LVM, the agreement between M-mode and 3DE for the detection of LV hypertrophy was 83% (Kappa=0.59; p<0.001). CONCLUSION: Although M-mode and 3DE correlate well for the calculation of LVM, there is a systematic difference between the two techniques leading to overestimation of LVM by the 1D technique. Thus, previously published cutoff values for normal LVM derived from M-mode may not apply for 3DE. However, the use of technique-specific partition values allows stratification of patients for the presence of LV hypertrophy with reasonable agreement.     

Determination of left ventricular mass by computed tomography

The purpose of this study was to determine the spatial distribution of lidocaine relative to blood flow in ischemic, normal and border zone canine myocardium. Ischemic zone tissue was distinguished from normal zone tissue by a special microsphere technique in adjacent sections 4 to 5 mm wide from the center to the lateral border of the ischemic region in 14 open chest dogs. Gamma-labeled microspheres were separated by a special technique from carbon-14 ([¹⁴C])-lidocaine in the same tissue sample. Blood flow (mean value ± 1 standard deviation) was reduced to 46 ± 25 percent of normal in the ischemic subepicardium and 17 ± 18 percent of normal in the subendocardium. [¹⁴C]-lidocaine was 0.56 ± 0.12 μg/g in normal myocardium 10 minutes after bolus injection of [¹⁴C]-lidocaine; it was reduced to 91 ± 15 percent of normal in ischemic subepicardium and 58 ± 12 percent of normal in the subendocardium. Blood flow and lidocaine concentration were uniformly lowest in gross samples from the central and intermediate ischemic zones, and highest in the gross samples from the border normal zone (p < 0.05). The values for flow and lidocaine in samples from the border ischemic zone were intermediate, that is, higher than values from central ischemic (p < 0.05) and lower than values from border normal zone samples (p < 0.05). However, the labeling technique for normal zone tissue revealed that the values of blood flow and lidocaine in the gross samples from the lateral border of the ischemic zone were intermediate between those of adjacent ischemic and normal samples because of the mixture of overlapping normal and ischemic tissues components—not because of a unique mildly ischemic region. Both blood flow and lidocaine concentration were lower in the subendocardial third than in the subepicardial third of the ischemic zone (p < 0.05) even after the contribution of normal zone tissue was subtracted, suggesting a gradient of ischemia across the transmural border zone.In conclusion, lidocaine is distributed uniformly in ischemic components from the center to the lateral border of the ischemic zone, but there is an endocardial to epicardial gradient. Both lateral and transmural border zone distributions must be considered to understand the mechanisms of drug effects in myocardial ischemia.     

实时三维超声心动图评价高血压患者左心室心肌质量及左心房功能

目的应用实时三维超声心动图技术评价高血压患者左心室质量、左心房功能,并对左心室质量的测量与常规M型方法进行对照。方法在37名健康人、39例高血压无左心室肥厚(NLVH)患者和27例高血压伴左心室肥厚(LVH)患者中进行了超声心动图检查。应用M型超声心动图测量左心室质量(LVM)并计算左心室质量指数(LVMI),实时三维超声测量左心室质量(LVM)及LVMI,左心房舒张末容积(LAEDV)、左心房收缩末容积(LAESV),左心房射血分数(LAEF),并比较高血压组(NLVH组、LVH组)与健康对照组之间的差异。结果对照组、高血压NLVH组、LVH组3组间左心室质量指数两种检测方法差异均具有统计学意义(P<0.05),并且发现三维超声检测结果较M型测量数值低。左心房收缩功能指标各组间差异均有统计学意义(P<0.05)。在左心室重构、心肌质量增大的高血压患者,左心房容积增大,而收缩功能减低。结论实时三维超声技术能够定量评价高血压患者左心房功能,测量左心室质量。     

Meta-analysis of accuracy of left ventricular mass measurement by three-dimensional echocardiography

Left ventricular (LV) hypertrophy is a fundamental prognostic factor in a variety of cardiac diseases. Three-dimensional echocardiography (3DE) has achieved better estimation of LV mass than 2-dimensional echocardiography. However, significant underestimation has often been reported, and no previous study has synthesized these data. The aim of this meta-analysis was to investigate if there has been improvement in the accuracy in LV mass measurement by 3DE over time. Studies comparing LV mass between 3DE and magnetic resonance imaging were eligible. A cumulative meta-analysis was performed to investigate improvement in accuracy, followed by subgroup and meta-regression analysis to reveal factors affecting the bias. A total of 25 studies including 671 comparisons were analyzed. Studies published in or before 2004 showed high heterogeneity (I(2) = 69%) and significant underestimation of LV mass by 3DE (-5.7 g, 95% confidence interval -11.3 to -0.2, p = 0.04). Studies published from 2005 to 2007 were still heterogenous (I(2) = 60%) but showed less systematic bias (-0.5 g, 95% confidence interval -2.5 to 1.5, p = 0.63). In contrast, studies published in or after 2008 were highly homogenous (I(2) = 3%) and showed excellent accuracy (-0.1 g, 95% confidence interval -2.2 to 1.9, p = 0.90). Investigation of factors affecting the bias revealed that evaluation of cardiac patients compared to healthy volunteers led to larger bias (p <0.05). In conclusion, this meta-analysis elucidates the underestimation of LV mass by 3DE, its improvement over the past decade, and factors affecting the bias. These data provide a more detailed basis for improving the accuracy of 3DE, an indispensable step toward further clinical application.     

Determination of left ventricular volume, ejection fraction, and myocardial mass by real-time three-dimensional echocardiography

Reconstructed three-dimensional (3-D) echocardiography is an accurate and reproducible method of assessing left ventricular (LV) functions. However, it has limitations for clinical study due to the requirement of complex computer and echocardiographic analysis systems, electrocardiographic/respiratory gating, and prolonged imaging times. Real-time 3-D echocardiography has a major advantage of conveniently visualizing the entire cardiac anatomy in three dimensions and of potentially accurately quantifying LV volumes, ejection fractions, and myocardial mass in patients even in the presence of an LV aneurysm. Although the image quality of the current real-time 3-D echocardiographic methods is not optimal, its widespread clinical application is possible because of the convenient and fast image acquisition. We review real-time 3-D echocardiographic image acquisition and quantitative analysis for the evaluation of LV function and LV mass.     

Reproducibility of left ventricular mass measurements by two-dimensional and M-mode echocardiography

Both two-dimensional and M-mode echocardiography provide accurate estimates of left ventricular mass. However, their reproducibility in serial studies has not been compared, although this issue is critical to evaluation of regression of hypertrophy. To determine which technique provides more reproducible estimates of left ventricular mass, three serial studies were performed prospectively in each of eight normal adults over 5 months. Both two-dimensional and M-mode echocardiograms were obtained at each of these 24 studies. Measurements were performed by two independent observers who did not know patient identity. For the two-dimensional method, left ventricular mass was determined with use of a computer light-pen system and the truncated ellipsoid formula. For the M-mode method, mass was calculated from Penn convention measurements with use of the cube formula. At study 1 the group mean left ventricular mass by two-dimensional echocardiography (115 +/- 20 g) did not differ from that by M-mode study (127 +/- 37 g, p = NS). However, serial estimates of left ventricular mass were more reproducible by two-dimensional echocardiography. The mean difference among the three serial two-dimensional studies in each individual was 4.8 +/- 4 g (4.2 +/- 3%) by the two-dimensional method, but was 18.5 +/- 13 g (14.9 +/- 10%) by the M-mode method (p = 0.01). Interobserver results for left ventricular mass by two-dimensional echocardiography correlated closely (r = 0.95, n = 24, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Nocturnal blood pressure predicts left ventricular mass index in normotensive elderly

Blood pressure (BP) predictors of left ventricular mass index (LVMI) were studied in 40 healthy normotensive (71.4 ±4.4 years) and 31 hypertensive (73.5 ±4.8 years) elderly community-dwelling subjects using short-axis cardiac cine magnetic resonance imaging and 24-h ambulatory BP monitoring. Mean night-time BPs were calculated from the average of readings during sleep and mean daytime BPs were calculated from the remaining recordings. The hypertensive subjects were all receiving anti-hypertensive therapy with angiotensin-converting enzyme (ACE) inhibitors, calcium-channel blockers, beta-blockers or diuretics. Nocturnal systolic BP was a strong predictor of LVMI in both normotensive ( β = 0.38, p = 0.02) and treated hypertensive ( β = 0.39, p = 0.03) subjects. By contrast, daytime systolic BP was a weaker predictor of LVMI in the treated hypertensives ( β = 0.36, p = 0.04) and did not predict LVMI in the normal subjects ( β = 0.27, NS). Nocturnal BP may partly explain the increase in LVMI with ageing in subjects thought to be normotensive on the basis of daytime clinic BP recordings.     

Association of gliclazide and left ventricular mass in type 2 diabetic patients

Diabetes is a state of increased oxidant stress and there is evidence that oxidation may play a role in the genesis of higher left ventricular mass. Gliclazide has been shown to possess free radical scavenging properties. We assessed whether gliclazide may have a beneficial effect on left ventricular mass via reducing 8-iso-prostaglandin F(2alpha) concentrations, a reliable marker of oxidant injury. A total of 41 patients were randomized into two groups. All patients had been taking glibenclamide for more than 3 months before being randomized to switch either an equipotent dose of gliclazide (n=21) or to continue on glibenclamide (n=20). Baseline characteristics were similar in both groups. At 6 months, gliclazide-treated patients showed a significant regression in left ventricular mass index compared with the glibenclamide-treated group (-16% versus 3%, P=0.003). Gliclazide patients had significantly lower plasma 8-iso-prostaglandin F(2alpha) compared with baseline (299+/-101 pg/ml versus 400+/-112 pg/ml, P=0.001) and the glibenclamide-treated patients (299+/-101 pg/ml versus 388+/-114 pg/ml, P=0.01) after 6-month therapy. The magnitude of left ventricular mass index regression correlated univariately with the magnitude of inhibition of 8-iso-prostaglandin F(2alpha) formation (r=0.74, P<0.0001). Multivariate analysis revealed that regression of left ventricular mass index significantly correlated with the changes of 8-iso-prostaglandin F(2alpha) (P<0.0001, adjusted R(2)=0.55). Our findings demonstrated for the first time that in addition to its primary hypoglycemia, gliclazide may have an additional effect on reducing left ventricular mass, possibly through attenuation of free radical formation.