Three-Dimensional Echocardiographic Reconstruction of the Left Ventricle by a Transesophageal Tomographic Technique

Accurate determination of left ventricular (LV) volume has important therapeutic and prognostic implications in patients with cardiac disease. Volume estimations by two-dimensional techniques are not very accurate due to geometric assumptions. Objectives: To validate LV volume determinations by a new transesophageal three-dimensional echocardiographic technique. We performed three-dimensional reconstruction of the LV using an echo-computed tomographic (CT) technique based on serial pullback parallel slice imaging technique in both in vitro and in vivo settings. Fourteen latex-balloons with various sizes (30–235 mL) and shapes (conical, pear shaped, round, elliptical, and aneurysms in various locations) filled with known volumes of water were imaged in a water bath. From the static three-dimensional image, the LV long axis was defined and the LV was sectioned perpendicular to this axis into 2-mm slices. The volume of each slice was calculated with the observer blinded to the actual volume as the product of the slice thickness and the manually traced perimeter of the slice and the LV volume as the sum of the volumes of the slices (Simpson's method). The calculated LV volume closely correlated with the actual volume (r = 0.99, P < 0.0001, calculated volume = 1.06x – 11.3, Δvolume =-5.7 ± 10.0 cc). Using the same system, transesophageal echocardiographic (TEE) images of the LV were obtained in 15 patients gated to respiration and ECG. Satisfactory dynamic three-dimensional reconstruction of the LV was possible in ten patients. The three-dimensional LV volumes (systolic and diastolic) using Simpson's method correlated well with those obtained from biplane or multiplane TEE images using the area length method (r = 0.89, P < 0.0001, y = 12.7 + 0.84x, Δvolume = 1.3 ± 18.1 cc). The LV major-axis diameters by the two methods showed very close correlations as well (r = 0.86, P < 0.0001, y = 19 + 0.74x, Δdiameter = 1.0 ± 7.2 mm). We conclude that three-dimensional LV volume calculation by the echo-CT technique is intrinsically sound, is independent of LV geometry, and with some limitations, is applicable in vivo.     

Value and limitations of transesophageal echocardiography in determination of left ventricular volumes and ejection fraction.

Several formulas exist for estimating left ventricular volumes and ejection fraction using conventional two-dimensional echocardiography from transthoracic views. Transesophageal imaging provides superior resolution of endocardial borders but employs slightly different scan planes. The estimation of left ventricular volumes by transesophageal echocardiography has not been validated in human patients. Therefore, the purpose of this study was to compare left ventricular volumes and ejection fraction derived from transesophageal short-axis and four-chamber images with similar variables obtained from ventriculography. End-diastolic and end-systolic volumes and ejection fraction were calculated using modified Simpson's rule, area-length and diameter-length models in 36 patients undergoing left ventriculography. Measurements of left ventricular length were obtained from the transesophageal four-chamber view and areas and diameters were taken from short-axis scans at the mitral valve, papillary muscle and apex levels. Data from transesophageal echocardiographic calculations were compared with end-diastolic volume (mean 172 +/- 90 ml), end-systolic volume (mean 91 +/- 74 ml) and ejection fraction (mean 52 +/- 15%) from cineventriculography using linear regression analysis. The area-length method (r = 0.88) resulted in a slightly better correlation with left ventricular end-diastolic volume than did Simpson's rule (r = 0.85) or area-length (r = 0.84) formulas. For end-systolic volume, the three models yielded similar correlations: Simpson's rule (r = 0.94), area-length (r = 0.93) and diameter-length (r = 0.95). Each of the methods resulted in significant underestimation of diastolic and systolic volumes compared with values assessed with angiography (p less than 0.003). Ejection fraction was best predicted by using the Simpson's rule formula (r = 0.85) in comparison with area-length (r = 0.80) or diameter-length (r = 0.73) formulas. Measurements of left ventricular length by transesophageal echocardiography were smaller for systole (mean 5.7 +/- 1.6 cm) and diastole (mean 7.7 +/- 1.2 cm) than values by ventriculography (mean 9.2 +/- 1.4 and 8.1 +/- 1.6 cm, respectively; p less than 0.0001), suggesting that underestimation of the ventricular length is a major factor contributing to the smaller volumes obtained by transesophageal echocardiography. In conclusion, currently existing formulas can be applied to transesophageal images for predicting left ventricular volumes and ejection fraction. However, volumes obtained by these models are significantly smaller than those obtained with angiography, possibly because of foreshortening in the transesophageal four-chamber view.     

Papillary Muscle Contribution to Ventricular Ejection in Normal and Hypertrophic Ventricles: A Transesophageal Echocardiographic Study

BACKGROUND: The interrelationship between left ventricular (LV) volume, stroke volume, and papillary muscle (PM) volume have not been studied. These volumes are relevant in understanding LV ejection mechanics in normal chambers and ascertaining whether differences exist between normal and hypertrophied LV chambers. METHODS AND RESULTS: PM basal areas were measured in short-axis transesophageal echocardiographic views and lengths were measured in long-axis views. PM volume was estimated by the formula for volume of a cone: 1/3 x PM base area x PM length. The formula for LV volume was as follows: LV volume = 2/3 x LV area x LV length. Of the initial 82 subjects with normal LV function studied by TEE, data on 71 are presented in this report. Thirty-two patients had normal LV size and wall thickness, and 39 had LV hypertrophy (LVH). PM volume/LV volume % in end-diastole (ED) and end-systole (ES) in normal muscles was 3.1 +/- 1.0 and 9.6 +/- 4.9, respectively. In LVH, the respective values were 5.1 +/- 2.0 (P < 0.05) and 13.5 +/- 4.9 (P < 0.05). For those with severe LVH, the values were 7.1 +/- 2.5 (P < 0.001) and 15.9 +/- 4.1 (P < 0.001), respectively, for ED and ES. Similar trends were seen in the PM volume/stroke volume relationships in normal and hypertrophic ventricles. CONCLUSIONS: PMs are larger and form a larger fraction of LV volume in LVH than in normal muscles. In patients with severe LVH, the contribution of PMs to ventricular ejection is more pronounced. PMs may, therefore, play a larger role in LV ejection in LVH than in normal ventricles (i.e., hypertrophied PM enhance the pump efficiency of LV ejection).     

Role of arterial hypertension in left ventricle hypertrophy in hemodialysis patients: an echocardiographic study.

To assess the role of arterial hypertension in left ventricle (LV) hypertrophy among hemodialysis patients, echocardiographic evaluation was performed in 10 hypertensive and 13 normotensive hemodialysis subjects matched for age, sex, race, duration of dialysis treatment and degree of interdialytic volume expansion. We excluded from the latter group patients with previous hypertension since hypertensive heart disease may persist after adequate blood pressure control. We also studied 17 normal controls and 10 non-uremic patients with essential hypertension. Comparisons between the two uremic groups showed that the hypertensive patients had a higher mass index (222 +/- 74 x 108 +/- 26, p = 0.0001) and posterior wall thickness (12 +/- 2 x 9 +/- 2, p = 0.0001) and a reduced LV radius/wall thickness ratio (4.4 +/- 0.7 x 5.8 +/- 1, p = 0.0001). There were no significant echocardiographic differences between normal controls and normotensive uremics. In contrast, compared to controls, hypertensive uremic patients showed an increased LV mass index (222 +/- 74 x 83 +/- 21, p = 0.0001) and posterior wall thickness (12 +/- 2 x 7 +/- 1, p = 0.0001) and a reduced LV radius/wall thickness ratio (4.4 +/- 0.7 x 6.5 +/- 1.1, p = 0.001), characterizing concentric hypertrophy. They also had ventricular dilation with larger LV dimensions than in controls (53 +/- 5 x 47 +/- 4, p = 0.004). In patients with essential hypertension, the mass index (135 +/- 22), wall thickness (11 +/- 1) and LV radius/wall thickness ratio (4.3 +/- 0.7) significantly differed (p = 0.0001) from those in the controls.(ABSTRACT TRUNCATED AT 250 WORDS)     

Initial clinical experience of real-time three-dimensional echocardiography in patients with ischemic and idiopathic dilated cardiomyopathy

The geometry of the left ventricle in patients with cardiomyopathy is often sub-optimal for 2-dimensional ultrasound when assessing left ventricular (LV) function and localized abnormalities such as a ventricular aneurysm. The aim of this study was to report the initial experience of real-time 3-D echocardiography for evaluating patients with cardiomyopathy. A total of 34 patients were evaluated with the real-time 3D method in the operating room (n = 15) and in the echocardiographic laboratory (n = 19). Thirteen of 28 patients with cardiomyopathy and 6 other subjects with normal LV function were evaluated by both real-time 3-D echocardiography and magnetic resonance imaging (MRI) for obtaining LV volumes and ejection fractions for comparison. There were close relations and agreements for LV volumes (r = 0.98, p <0.0001, mean difference = -15 +/- 81 ml) and ejection fractions (r = 0.97, p <0.0001, mean difference = 0.001 +/- 0.04) between the real-time 3D method and MRI when 3 cardiomyopathy cases with marked LV dilatation (LV end-diastolic volume >450 ml by MRI) were excluded. In these 3 patients, 3D echocardiography significantly underestimated the LV volumes due to difficulties with imaging the entire LV in a 60 degrees x 60 degrees pyramidal volume. The new real-time 3D echocardiography is feasible in patients with cardiomyopathy and may provide a faster and lower cost alternative to MRI for evaluating cardiac function in patients.     

Clinical utility of new real time three-dimensional transthoracic echocardiography in assessment of mitral valve prolapse

BACKGROUND: Noninvasive and accurate assessment of mitral valve anatomy has become integral in the presurgical evaluation of patients with mitral valve prolapse (MVP). Recently developed real time three-dimensional (RT3D) ultrasound allows online acquisition, rendering, and can provide accurate information on cardiac structures. We sought to evaluate the feasibility of RT3D for the assessment of MVP segments when compared with transesophageal echocardiography (TEE) and intraoperative findings. METHODS: We examined 42 patients with MVP using RT3D, two-dimensional (2D) transthoracic echocardiography (TTE) and TEE. For RT3D analysis, cropping planes were used to slice the 3D volume on line to visualize the prolapsed segments of the mitral valve leaflets. The mitral valve was divided into six segments based on the American Society of Echocardiography's recommendations. Two experienced cardiologists evaluated echocardiographic images. RESULTS: Adequate RT3D images of the mitral valve were acquired in 40 out of 42 patients. The sensitivity and specificity of RT3D for defining prolapsed segments when compared with TEE were 95% and 99%, respectively (anterior leaflet: 96% and 99%, posterior leaflets: 93% and 100%, respectively). The sensitivity and specificity of TTE were 93% and 97%, respectively (anterior leaflet: 96% and 98%, posterior leaflets: 90% and 97%, respectively). Interobserver agreement for RT3D (Kappa 0.95, 95% confidence interval [CI] 0.91-1.00) was significantly greater than for TTE (Kappa 0.85, 95% CI 0.78-0.93) (P < 0.05). The elapsed time for completion of RT3D (14.4 +/- 2.8 min) was shorter than for TEE (26.4 +/- 4.7 min, P < 0.0001) and TTE (19.0 +/- 3.1 min, P< 0.0001). CONCLUSIONS: RT3D is fast, accurate, and highly reproducible for assessing MVP.     

Quantitative validation of cineangiographic axial oblique biplane left ventricular volume measurement

Axial oblique left ventriculography allows unique visualization of acquired and congenital cardiac lesions. However, validation of the accuracy of left ventricular (LV) volume with axial oblique projections is limited and clouded by orthogonal violations between biplane projections. Biplane cineradiographic volume measurement of 17 LV casts employing the axial projection 35 degrees right anterior oblique/55 degrees left anterior oblique/30 degrees cranial (35 degrees RAO/55 degrees LAO/30 degrees Cr) was performed and compared to the conventional postero-anterior/lateral (PA/Lat) and 30 degrees right anterior oblique/60 degrees left anterior oblique (30 degrees RAO/60 degrees LAO) views. LV volume was calculated from biplane cineradiograms by area length and Simpson's rule method. True LV volume by water displacement was 33 +/- 28 (mean +/- S.D.), range 15 to 112 ml. LV cast volume calculated by the area length method from cineradiograms was overestimated (p less than 0.002) but no different by Simpson's rule method (pNS). The ideal correlation was best approximated by the 35 degrees RAO/55 degrees LAO/30 degrees Cr biplane view calculated by Simpson's rule, r = 0.99, y = 3.5 + 0.9x, and standard error of estimate (SEE) = 4.3 ml. Biplane LV angiography with the axial projection permitted accurate LV volume measurement, and Simpson's rule provided the best representation of true volume.     

Prediction of Intraoperative Hypovolemia in Patients with Left Ventricular Hypertrophy: Comparison of Transesophageal Echocardiography and Swan-Ganz Monitoring

We have compared the pulmonary artery catheterization and transesophageal echocardiography (TEE) as an index of left ventricular (LV) volume in 32 patients with LV hypertrophy. Twenty-four of the 32 patients had episodes of low LV volume using TEE. Of these 24 patients, five had low pulmonary capillary wedge pressures ranging from 6–11 mmHg (mean ± SD, 8.8 ± 1.9 mmHg). Nineteen patients had elevated pulmonary capillary wedge pressures (PCWPs) (mean 18.3 ± 2.2 mmHg) and TEE showed signs of hypovolemia. Volume repletion resulted in increased blood pressure in these patients. The poor correlation between PCWP and LV end-diastolic volume in the present study may result from impaired compliance of the ventricle. Diagnosis of hypovolemia should not be solely based on hemodynamic parameters alone and TEE provides accurate estimates of ventricular volume.     

Impact of cardiac resynchronization therapy using hemodynamically optimized pacing on left ventricular remodeling in patients with congestive heart failure and ventricular conduction disturbances

OBJECTIVES: We sought to investigate the impact of six months of cardiac resynchronization therapy (CRT) on echocardiographic variables of left ventricular (LV) function. BACKGROUND: Cardiac resynchronization therapy has recently been introduced as a new therapeutic modality in patients with advanced heart failure (HF) and conduction abnormalities. However, most studies have only investigated the early hemodynamic effects of CRT. METHODS: Twenty-five patients (12 women and 13 men; 59.8 +/- 5.1 years old) with advanced HF caused by ischemic (n = 7) or idiopathic dilated cardiomyopathy (n = 18) and a prolonged QRS complex were analyzed. All patients underwent early hemodynamic testing with a randomized testing protocol; echocardiographic measurements were compared before implantation and after six months of CRT. RESULTS: Left ventricular end-diastolic and end-systolic diameters (LVEDD and LVESD, respectively) were significantly reduced after six months (LVEDD from 71 +/- 10 to 68 +/- 11 mm, p = 0.027; LVESD from 63 +/- 11 to 58 +/- 11 mm, p = 0.007), as were LV end-diastolic and end-systolic volumes (LVEDV from 253 +/- 83 to 227 +/- 112 ml, p = 0.017; LVESV from 202 +/- 79 to 174 +/- 101 ml, p = 0.009). Ejection fraction was significantly increased (from 22 +/- 7% to 26 +/- 9%, p = 0.03). "Nonresponders," with regard to LV volume reduction, had significantly higher baseline LVEDV, compared with "responders" (351 +/- 52 vs. 234 +/- 74 ml, p = 0.018). Overall, there was only mild mitral regurgitation at baseline, with a minor reduction by semiquantitative analysis. The results of early hemodynamic testing did not predict the volume response. CONCLUSIONS: Cardiac resynchronization therapy may lead to a reduction in LV volumes in patients with advanced HF and conduction disturbances. Volume nonresponders have significantly higher baseline LVEDV.     

Three-Dimensional Echocardiography: Precision and Accuracy of Left Ventricular Volume Measurement Using Rotational Geometry with Variable Numbers of Slice Resolution

We developed a new, rapid (6 seconds) acquisition technique allowing collection of approximately six through nine apical rotational tomograms for three-dimensional (3-D) echocardiography. To justify an appropriate sampling density for precise and accurate measurement of chamber volumes in left ventricles with complicated shape, we designed a validation study in vitro using six canine heart specimens with irregular, asymmetric left ventricles with known volumes (28.5 to 104.3 ml; mean, 71.2 ml). The number of equally spaced slices were incrementally deleted from the original high resolution scans (48 slices) to 2 slices in 3-D reconstruction. We created subgroups of 48- and 36-, 24- and 16-, 12- and 8-, 6- and 4-, and 3- and 2-component slices to compare left ventricular (LV) volumes measured in 3-D images with different slice resolution with the reference standard measured in the specimen. The accuracy and precision of LV volume were relatively constant in the subgroup of 4- and 6- through 36- and 48-component slices. When the subgroup with 6- and 4-component slices was used, the correlation was r = 0.991, P < 0.0001, root mean-square percent error of 5.0%, bias of 0.5 ± 3.7 ml, and interobserver variability of 5.0%. With the reduction in component slices equal or less than three, the accuracy decreased significantly (root-mean-square percent error = 8.1% and bias = -2.0 ± 5.7 ml) compared with higher slice resolutions. This study demonstrated that 3-D echocardiography using apical rotational techniques can accurately quantify LV volume in the canine heart specimens with irregular shapes with as few as 4–6 axial slices. The rapid 3-D acquisition technique is therefore anticipated to yield precise and accurate LV volumetry.     

In Vitro Feasibility and Accuracy of Three-Dimensional Echocardiography for Ventricular Volume Assessment in Very Small Hearts

To evaluate the in vitro accuracy of three-dimensional echocardiography (3-DE) for estimation of ventricular volume in very small hearts, left ventricular (LV) volume was determined by 3-DE in the excised hearts of 10 guinea pigs and 10 rabbits, and right ventricular (RV) volume was determined in 20 rabbits. The effect of edge enhancement, Sigma filter, and slice distance (1 mm versus 0.5 mm) was assessed in each heart. True volumes were obtained from ventricular casts. Mean cast volume was 1.38 ± 0.83 mL for LVs and 1.63 ± 1.01 mL for RVs. Correlations between 3-DE and true volumes were r > 0.99 (P < 0.0001) for both ventricles. Accuracy was not affected by ventricular type, slice distance, or Sigma filter. Mean percent difference from true volume was significantly less (P = 0.03) with edge enhancement. Ventricular volume can be assessed reliably by 3-DE in very small hearts. The edge enhancement feature improved the accuracy of the measurements.     

Quantification of left ventricular myocardial mass in humans by nuclear magnetic resonance imaging

The ability of NMRI to assess LV mass was studied in 20 normal males. By means of a 1.5 Tesla GE superconducting magnet and a standard spin-echo pulse sequence, multiple gated short-axis and axial slices of the entire left ventricle were obtained. LV mass was determined by Simpson's rule with the use of a previous experimentally validated method. The weight of the LV apex (subject to partial volume effect in the short-axis images) was derived from axial slices and that of the remaining left ventricle from short-axis slices. The weight of each slice was calculated by multiplying the planimetered surface area of the LV myocardium by slice thickness and by myocardial specific gravity (1.05). Mean +/- standard deviation of LV mass and LV mass index were 146 +/- 23.1 gm (range 92.3 to 190.4 gm) and 78.4 +/- 7.8 gm/m2 (range 57.7 to 89.4 gm/m2), respectively. Interobserver agreement as assessed by ICC was high for determining 161 individual slice masses (ICC = 0.99) and for total LV mass (ICC = 0.97). Intraobserver agreement for total LV mass was also high (ICC = 0.96). NMRI-determined LV mass correlated with body surface area: LV mass = 55 + 108 body surface area, r = 0.83; with body weight: LV mass = 26 + 0.77 body weight, r = 0.82; and with body height: LV mass = 262 +/- 5.9 body height, r = 0.75. Normal limits were developed for these relationships. NMRI-determined LV mass as related to body weight was in agreement with normal limits derived from autopsy literature data.(ABSTRACT TRUNCATED AT 250 WORDS)     

Cross-sectional multiplane transesophageal echocardiographic measurements: comparison with standard transthoracic values obtained in the same setting

BACKGROUND: Several algorithms developed for cost-effective use of transesophageal echocardiography (TEE) propose elimination of "screening" transthoracic echocardiographic (TTE) studies. Cross-sectional measurements obtained by TTE (left atrial diameter [LAD], left ventricular internal dimensions in diastole and systole [LVIDd, LVIDs], septal and posterior wall thickness in diastole [VSTd, PWTd], LV end-diastolic and end-systolic volumes [LVEDV and LVESV], and LV ejection fraction [LVEF]) have not been standardized for TEE. METHODS: Forty-six patients (age 27 to 85 years, 60 +/- 13 years, 25 [54%] women) underwent TEE and TTE studies. TTE was performed while the TEE probe was in place and the patient was still sedated. Standard TTE measurements were compared with corresponding TEE values obtained from mid-esophageal and transgastric views. RESULTS: Standard TTE measurements compared favorably with those obtained by TEE at the mid-esophageal three-chamber view for LAD (3.9 +/- 0.6 cm vs 4.0 +/- 0.7 cm, P = NS) and at the transgastric long-axis view for LVIDd (4.6 +/- 0.8 cm vs 4.7 +/- 0.8 cm, P = NS), LVIDs (3.1 +/- 0.9 cm vs 3.1 +/- 0.9 cm, P = NS), and VSTd (0.95 +/- 0.18 cm vs 0.98 +/- 0.19 cm, P = NS). Biplane TTE and TEE measurements of LVEDV (106 +/- 35 ml vs 112 +/- 38 ml, P = NS), LVESV (37 +/- 23 ml vs 37 +/- 25 ml, P = NS), and LVEF (67 +/- 14% vs 69 +/- 14%, P = NS) also correlated closely. The negative predictive values of TEE measurements for excluding abnormal LAD, LVIDd, VSTd, PWTd, and LVEF as defined by TTE were 83%, 94%, 95%, 97%, and 97%, respectively. CONCLUSION: Cross-sectional TEE measurements as obtained in this study are equivalent to standard TTE dimensions and provide reliable information that may facilitate interpretation of TEE studies in the absence of TTE information.     

Usefulness of three-dimensional echocardiography for the evaluation of mitral valve prolapse: an intraoperative study

BACKGROUND AND AIM OF THE STUDY: The study aim was to evaluate the feasibility of intraoperative three-dimensional (3D) transesophageal echocardiography (TEE) in patients referred for mitral valve prolapse (MVP) repair and to compare two-dimensional (2D) TEE and 3D TEE and surgical findings. METHODS: Forty-six patients (mean age 67 +/- 11 years) underwent 3D TEE intraoperatively. Measurements were made of the posterior part of mitral annulus circumference (PMAC), and the width of mitral valve surgical resection on the mitral annulus (WMVR). Using 3D TEE, MVP topography was described, and PMAC in diastole and the width of implantation of MVP on the mitral annulus (WMVP) in systole were measured. RESULTS: 3D TEE was successful in 42 patients (91%). 2D and 3DTEE correctly predicted MVP localization in 38 (90%) and 36 (86%) patients, respectively (p = NS). 3D TEE and surgical PMAC were 89 +/- 13 and 93 +/- 21 mm, respectively (p = 0.01, R = 0.42). WMVR and WMVP were 28 +/- 11 mm and 26 +/- 11 mm, respectively (p <0.0001, R = 0.82). WMVR/anatomic PMAC (0.29 +/- 0.11) and WMVP/3D echo PMAC (0.32 +/- 0.11) were correlated (p <0.0001, R= 0.69). CONCLUSION: Intraoperative 3D TEE evaluation of MVP is feasible. MVP width and its ratio to the mitral annulus were assessed, and found to correlate with surgical findings. These 3D data may be of value to the surgeon when performing mitral valve repair.     

X线心室造影单平面Simpson方法计算右心室容积的可行性研究

目的　探讨X线心室造影单平面Simpson法计算右心室容积的可行性,为计算右心室容积、评价右心室功能提供一个实用的临床方法。方法　对 15枚人的右心室铸型逐个进行相当于体内右前斜位 30°的电影摄影,依据右心室形态的半月模型采用单平面Simpson法计算右心室铸型容积。采用阿基米德原理计算右心室铸型的实际容积。结果　右心室铸型的实际容积为 ( 64 23±24 51)ml, X线心室造影单平面Simpson法计算得出的右心室容积为(58 04±24 45)ml。采用本模型计算得出的右心室容积值低估右心室实际容积值为 (6 19±12 38)ml,但二者差异无统计学意义(t=1 936, P=0 073)。直线相关与回归分析表明,X线心室造影单平面Simpson法计算右心室容积与右心室铸型的实际容积呈显著正相关 (r=0 983,P<0 01 )。回归方程为:右心室铸型的实际容积=1 074×(X线心室造影单平面Simpson法右心室容积)。结论　采用单平面Simpson法计算右心室容积有较高准确性,值得临床进一步研究。     

Clinical Determinations of Volumes of Normal and Aneurysmatic Left Ventricles by Three-Dimensional Transesophageal Echocardiography

Biplane methods of determining left ventricular volumes are inaccurate in the presence of aneurysmal distortions. Multiplane transesophageal echocardiography, which provides multiple, unobstructed cross-sectional views of the heart from a single, stable position, has the potential for more accurate determinations of volumes of irregular cavity forms than the biplane methods. The aim of the study was to determine the feasibility of three-dimensional measurements of ventricular volumes in patients with normal and aneurysmatic left ventricles by using multiplane transesophageal echocardiography. With the echotransducer in the mid-esophageal (transesophageal) position, nine echo cross-sectional images of the left ventricle in approximately 20 degrees angular increments were obtained from each of 29 patients with coronary artery disease who had undergone biplane ventriculography during diagnostic cardiac catheterization. In 17 of these 29 patients, echo cross-sectional images of the left ventricle with the echotransducer in transgastric position were also obtained. End-diastolic volume, end-systolic volume, and ejection fraction were determined from multiplane transesophageal echocardiographic images and biplane ventriculographic images by the disc-summation method and compared with each other. In another ten patients with indwelling pulmonary artery catheters, stroke volumes calculated from multiplane transesophageal echocardiographic images were compared with those derived from thermodilution cardiac output measurements. Correlations between biplane ventriculographic and multiplane transesophageal echocardiographic measurements were higher in the ten patients with normal ventricular shape [for end-diastolic volumes, r = 0.91, SEE = 19 ml; for end-systolic volumes, r = 0.98, SEE = 9.3 ml; for ejection fractions (EFs), r = 0.91, SEE = 5.4%] than in the 19 patients with ventricular aneurysms (for end-diastolic volumes, r = 0.61, SEE = 31.5 ml; for end-systolic volumes, r = 0.66, SEE = 32.5 ml; for EFs, r = 0.79, SEE = 8%). Correlations between echocardiographic volumes from the transesophageal and transgastric transducer positions were high independent of left ventricular geometry (for end-diastolic volumes, r = 0.84, SEE = 13.1 ml; for end-systolic volumes, r = 0.98, SEE = 9.6 ml; for EFs, r = 0.97, SEE = 3.4%). In 12 observations (4 normal and 8 aneurysmal) from the ten patients with indwelling pulmonary artery catheters, correlation between stroke volumes determined from thermodilution cardiac output measurements and those derived from multiplane transesophageal echocardiographic images was high (r = 0.91, SEE = 6 ml). The results indicate that three-dimensional measurements of volumes of irregular and distorted left ventricles are feasible with multiplane transesophageal echocardiography. This method may be more accurate than biplane methods, especially in the presence of left ventricular aneurysms.     

Comparison of transthoracic and intraoperative transesophageal color flow Doppler assessment of mitral and aortic regurgitation

BACKGROUND: We examined the agreement between transthoracic echocardiography (TTE) and intraoperative prepump transesophageal echocardiography (TEE) in the assessment of left-sided regurgitant lesions and echocardiographic variables associated with grading discrepancies. METHODS: The TTE and prepump TEE studies of 54 patients undergoing aortic-valve replacement for aortic stenosis were reviewed. Agreement and correlation in assessment of aortic (AR) and mitral regurgitation (MR) severity were evaluated. RESULTS: There was no significant difference between mean TTE and prepump TEE grading of MR (0.23 +/- 0.19 vs. 0.21 +/- 0.15 jet area/area of the left atrium, p = 0.49), but the correlation between the two methods was weak (r = 0.40, p = 0.003), with an exact agreement of 54%. Prepump TEE tended to grade AR as more severe (mean grade 1.43 +/- 0.94 vs. 1.24 +/- 0.75, p = 0.058). The correlation between the two methods in AR assessment was fair (r = 0.70, p = 0.0001) with an agreement of 59%. For MR and AR grading, no significant correlations between valvular regurgitation severity and blood pressure differences between preoperative TTE and prepump TEE were found. In 17% of cases, discrepancies in identifying severe mitral or aortic valve regurgitation could have affected patient management. CONCLUSIONS: There is modest agreement in MR and AR assessment between TTE and prepump TEE. Cardiologists, cardiac surgeons, and anesthesiologists must be aware of differences between these methods when using prepump TEE to guide intraoperative decisions.     

Quantitation of right ventricular volumes and ejection fraction by three-dimensional echocardiography in patients: comparison with magnetic resonance imaging and radionuclide ventriculography

Three-dimensional echocardiography (3DE) provides volumetric measurements without geometric assumptions. Volume-rendered 3DE has been shown to be accurate for the measurement of right ventricular (RV) volumes in vitro and in animal studies; however, few data are available regarding its accuracy in patients. This study examined the accuracy of 3DE for quantitation of RV volumes and ejection fraction (EF) in patients, compared to magnetic resonance imaging (MRI) and radionuclide ventriculography (RNV). Twenty patients underwent MRI, gated equilibrium RNV, and 3DE using rotational acquisition from both the transesophageal and transthoracic approaches. RV volumes and EF were calculated from the 3DE data using multislice analysis (true Simpson's rule). RV volumes calculated by MRI (end-diastolic volume (EDV) 109.4 +/- 34.3 mls, end-systolic volume (ESV) 59.6 +/- 31.0 mls, and EF 47.7 +/- 17.1%) agreed closely with 3DE. For transesophageal echocardiography, EDV was 108.1 +/- 29.7 mls (r = 0.86, mean difference 1.3 +/- 17.8 mls); ESV was 62.5 +/- 23.8 mls (r = 0.85, mean difference 2.8 +/- 15.1 mls); and EF was 43.2 +/- 11.7% (r = 0.84, mean difference 4.5 +/- 9.7%). For transthoracic echocardiography, EDV was 107.7 +/- 27.5 mls (r = 0.85, mean difference 1.6 +/- 18.2 mls); ESV was 59.7 +/- 22.1 mls (r = 0.93, mean difference 3.2 +/- 19.6 mls); and EF was 45.2 +/- 11.5% (r = 0.86, mean difference 2.0 +/- 9.4%). There were close correlations, small mean differences and narrow limits of agreement between RNV-derived EF (43.4 +/- 12.1%) and both transesophageal (r = 0.95 mean difference 0.2 +/- 3.7%) and transthoracic 3DE (r = 0.95, mean difference 1.8 +/- 5.4%). Three-dimensional echocardiography is a promising new method of calculating RV volumes and EF, comparing well with MRI and RNV. The accuracy of transthoracic 3DE was comparable to that of the transesophageal approach. Three-dimensional echocardiography has the potential to be useful in the clinical assessment of RV disorders.     

实时三维超声心动图与磁共振对比评价左心室射血分数≥45%患者的左心室容量

目的:评价实时三维超声心动图(RT3D)测量左心室射血分数(LVEF)≥45% 成年人左心室容量的准确性和重复性.方法:选取因各种不同原因进行心脏磁共振(MRI)检查显示 LVEF ≥45%的患者37例,同时进行RT3D检查.RT3D检查采用Philips iE-33型超声心动图仪,左心室容量及左心室功能的分析通过TomTec工作站用人工描记法完成,并与MRI所得结果相比较.结果:MRI测量的左心室舒张末期容量(EDV)为:60～208.76(110.48±33.50)ml,左心室收缩末期容量(ESV)为:19～102.4(45.80±17.84 )ml,LVEF为:45.40～71.10(59.13±7.24)%.RT3D测量的EDV为:42.8～ 211.9(100.64±34.48)ml,ESV为:14.30 ～94.54(44.08 ±17.62)ml,LVEF为:35.1～73.4(56.70±7.02)%.与MRI相比,RT3D低估EDV(P＜0.01,r=0.842,y=0.867x+4.88,SEE=18.86ml),二者平均相差(-9.84±38.26) ml.RT3D同时低估ESV,二者相比差异无统计学意义(P＞0.05,r=0.846,y=0.835x+5.82,SEE=9.53 ml),二者平均相差(-1.71±19.68)ml.RT3D所测的LVEF稍小于MRI所测得的LVEF,二者相比差异有统计学意义(P＜0.05,r=0.616,y=0.597x+21.38,SEE=5.61%),平均相差(-2.42±12.5 )%.在不同观察者间及观察者自身不同时间内测量的RT3D,结果显示良好的重复性.结论:与MRI相比,RT3D测量成人患者的左心室容量及LVEF有较好的准确性和重复性.     

Accurate, simplified and rapid three-dimensional echocardiographic volume quantifications: Comparison of different algorithms in symmetric and asymmetric left ventricular geometry

OBJECTIVE: A comparative investigation of dynamic three-dimensional freehand echocardiography (D3DFE) and magnetic resonance imaging (MRI) was conducted to determine the accuracy and rapidity of the average rotation method (ARM) and the disk summation method (DSM) for volumetric analysis. METHODS: In 15 patients with an asymmetric left ventricle and 12 normal subjects, end-diastolic and end-systolic left ventricular volumes were assessed by D3DFE and by MRI. Both DSM and ARM were used for volume determination. All echocardiographic readings were performed by two examiners blinded to each other and to the MRI results. The times needed for echocardiographic data acquisition and volumetric analysis with either algorithm were determined. RESULTS: Correlation between ARM and MRI measurements was tighter than between DSM and MRI measurements (end-diastolic volume: r=0.95, P<0.0001 versus r=0.94, P<0.0001 in asymmetric ventricles; and r=0.97, P<0.0001 versus r=0.96, P<0.0001 in symmetric ventricles; end-systolic volume: r=0.94, P<0.0001 versus r=0.93, P<0.0001 in asymmetric ventricles and r=0.96, P<0.0001 versus r=0.94, P<0.0001 in symmetric ventricles). In addition, ARM analysis was less time-consuming than DSM (6.4+/-0.4 min versus 7.6+/-0.3 min, P<0.05). CONCLUSIONS: For D3DFE, ARM is the most accurate and rapid approach to left ventricular volume determination. ARM benefits from advanced two-dimensional imaging and can be easily added to any standard transthoracic echocardiographic examination.