Evaluation of left atrial size in patients with atrial arrhythmias: comparison of standard 2D versus real time 3D echocardiography

AIM: Two-dimensional echocardiography may not correctly indicate size in nonspherical atria. The present study compares different parameters of left atrial size evaluated by standard two-dimensional echocardiography with left atrial volume measured using three-dimensional echocardiography (3DE). METHODS AND RESULTS: One hundred seventy consecutive patients with a history of atrial arrhythmias were studied by standard two-dimensional and by real time 3DE. Of these 166 (98%) recordings were of sufficient quality for interpretation by both imaging techniques. The following parameters of left atrial size were measured: parasternal long axis diameter (PLAX), apical 4-chamber short-axis diameter (4CH short axis), apical 4-chamber (4CH long axis), and 2-chamber long-axis diameters and planimetry areas. Two-dimensional-derived left atrial volumes were calculated by using both single plane (4CH area-length) and biplane area-length methods. The 2D parameters were then correlated with left atrial volume measured by 3D echocardiography. Linear regression analysis showed moderate correlation for 4-chamber planimetry area (r = 0.76, P < 0.0001) and 2D-derived volume calculations (r of 4CH single plane area-length LA volume = 0.74 and biplane area-length LA volume = 0.78, P < 0.0001). Diameters correlated less well with 3DE volume (r of PLAX = 0.67, 4CH short axis = 0.68, 4CH long axis = 0.63, P < 0.0001 respectively). CONCLUSION: The results demonstrate that measurements of dimensions using standard echocardiography are of limited accuracy to assess left atrial volume. If 3DE is not available, 4-chamber planimetry area is a valid simple parameter for evaluating left atrial size in clinical practice. Two-dimensional-derived volume by biplane area-length method was only slightly better correlated with 3DE volume than 4-chamber planimetry area.     

Left and right atrial volume by freehand three-dimensional echocardiography: in vivo validation using magnetic resonance imaging.

INTRODUCTION: Measurement of left and right atrial size is important for the management of arrhythmias, valvular and congenital heart disease. We have demonstrated that freehand three-dimensional (3D) echocardiography is more accurate and reproducible than two-dimensional (2D) echocardiography for measurement of left ventricular mass and volume. However, no prior study has validated the accuracy of freehand 3D for the determination of left or right atrial volume. METHODS: End-systolic (maximum) left and right atrial volumes were determined in 21 volunteer patients and normal subjects by one, two, and freehand 3D transthoracic echocardiography and compared to volumes obtained by gradient recalled magnetic resonance imaging. Three-dimensional echocardiographic determination of atrial volume was obtained using an acoustic spatial locator, a line-of-intersection display, and a surface reconstruction algorithm. Two-dimensional echocardiographic atrial volumes were obtained from apical biplane images of the left atrium and an apical single plane image of the right atrium using a summation of disks method. One-dimensional (ID) estimates of left atrial volume were determined by cubing the M-mode ID antero-posterior dimension obtained on the parasternal long axis view. RESULTS: An excellent correlation was Obtained between freedhand 3D echocardiography and magnetic resonce imaging (MRI) for the left atrium (r = 0.90, SEE=9.6 ml) and for the right atrium (r = 0.91, SEE = 8.8 ml) with a small bias (left atrium 5.25 ml, right atrium 12.06 ml) and narrow limits of agreement (left atrium 22.14 ml, right atrium 25.54 ml). Two-dimensional echocardiography correlated less well (left atrium r = 0.87, SEE = 10.23 ml, right atrium r = 0.79, SEE = 19.74 ml), and had a higher bias (left atrium 14.46 ml, right atrium 8.99 ml) and larger limits of agreement (left atrium 24.37 ml, right atrium 41.16 ml). One-dimensional estimates of left atrial volume correlated poorly with magnetic resonance determined left atrial volume (r = 0.80, SEE = 6.61 ml) and had unacceptably high bias (45.09 ml) and limits of agreement (35.52 ml). Interobserver variability was lowest for 3D echocardiography (left atrium 7.2 ml, 11%, right atrium 8.7 ml, 16%). CONCLUSIONS: Freehand 3D echocardiography using the line of intersection display for guidance of image positioning and a polyhedral surface reconstruction algorithm is a valid, accurate, reproducible method for determining left and right atrial volume in humans that is comparable to magnetic resonance imaging and is superior to current ID and 2D echocardiographic techniques.     

Left ventricular volume from paired biplane two-dimensional echocardiography.

To evaluate the applicability of two-dimensional echocardiography to left ventricular volume determination, 30 consecutive patients undergoing biplane left ventricular cineangiography were studied with a wide-angle (84 degrees), phased-array, two-dimensional echocardiographic system. Two echographic projections were used to obtain paired, biplane, tomographic images of the left ventricle. We used the short-axis view (from the precordial window) as an anolog of the left anterior oblique angiogram, and the long-axis, two-chamber view (from the apex impulse window) as a right anterior oblique angiographic equivalent. A modified Simpson's rule formula was used to calculate systolic and diastolic left ventricular volumes from the biplane echogram and the biplane angiogram. These methods correlated well for ejection fraction (r = 0.87) and systolic volume (r = 0.90), but only modestly for diastolic volume (r = 0.80). These correlations are noteworthy because 65% of the patients had significant segmental wall motion abnormalities. The volumes determined from the minor-axis dimensions of M-mode echograms in 23 of the same patients correlated poorly with angiography.     

Two-dimensional echocardiographic evaluation of the size, function and shape of the left ventricle in chronic aortic regurgitation: comparison with radionuclide angiography

To evaluate the usefulness of two-dimensional echocardiography in asymptomatic or minimally symptomatic patients with significant aortic regurgitation and left ventricular enlargement, left ventricular size and function measurements obtained by a nongeometric technique, gated blood pool radionuclide angiography, were compared with measurements made by several two-dimensional echocardiographic methods in 20 patients. Left ventricular size was best assessed by an apical biplane modified Simpson's rule algorithm obtained by computer-assisted planimetry. For end-diastolic volume, r = 0.95 and standard error of the estimate = 25 ml; for end-systolic volume, r = 0.94 and standard error of the estimate = 16 ml. A newly introduced simplified two-dimensional method obviating the need for planimetry and using multiple axis measurements yielded satisfactory results, although volumes larger than 300 ml were markedly underestimated. Evaluation of volumes from a single minor axis measured directly from two-dimensional images and M-mode tracings obtained under two-dimensional echocardiographic control was inadequate for clinical use. Ejection fraction was correctly assessed by the modified Simpson's rule method as well as by the simplified two-dimensional method (r = 0.81 to 0.83, standard error of the estimate = 7%). However, when methods without planimetry were further simplified, a satisfactory correlation was no longer obtained. The M-mode approach using a corrected cube formula also provided an accurate estimation of ejection fraction, a finding that is attributed to the absence of regional wall motion abnormalities in this group of patients, the ability to locate the M-mode beam more adequately under two-dimensional control and the persistence of an ellipsoidal configuration and a circular cross section in the left ventricular chamber. The data indicate that two-dimensional echocardiography is a valuable approach to the assessment of left ventricular size and function in these patients. Moreover, this approach provides a practical and convenient way of improving M-mode evaluation of function and of determining left ventricular shape, thus permitting adequate selection of geometric algorithms for volume calculations.     

Left atrial volume determination by echocardiography

To validate echocardiographic left atrial volume measurements, 25 patients with mitral stenosis were studied before and after mitral balloon valvuloplasty. Seven normals served as controls. The modified Simpson's rule was used for echocardiographic and angiographic left atrial volume determination from two orthogonal planes. Left atrial antero-posterior diameter was measured from parasternal long axis view and supero-inferior and medio-lateral diameters from apical four-chamber view. Transthoracic echocardiographic left atrial volume correlated well, but systematically underestimated angiographic left atrial volume (y=0.4x+27, r=0.92). Monoplane transesophageal echocardiography did not improve correlation, nor the underestimation. Out of the several left atrial diameters, antero-posterior dimension showed the closest correlation with angiographic volume (r=0.91), which persisted after exclusion of patients with atria >400 ml (r=0.84). Futhermore, relative changes of antero-posterior diameter after mitral valvuloplasty were closely related to the relative changes observed in left atrial volume (r=0.82). Our results suggest that, in spite of a consistent underestimation, bidimensional, transthoracic echocardiographic and angiographic left atrial assessment correlate closely. Moreover, it is suggested that the mere antero-posterior diameter from transthoracic two-dimensional image is sufficient in clinical practice for routine follow-op of left atrial volume.     

Best method in clinical practice and in research studies to determine left atrial size.

Although the anteroposterior dimension of the left atrium is universally used in clinical practice and research, we hypothesized that it may be an inaccurate surrogate for volume because its use is based on the unlikely assumption that there is a constant relation among atrial dimensions. The following measurements of the left atrium were made at end ventricular systole: (1) M-mode-derived anteroposterior linear dimension from the parasternal long-axis view; (2) digitized planimetry of the left atrial (LA) cavity from the apical 4-chamber view; and (3) digitized planimetry of the LA cavity from the apical 2-chamber view. The following volume calculations were obtained from these digital measurements: (1) volume derived from the M-mode dimension assuming a spherical shape; (2) volume derived from the single plane area-length of apical 4-chamber view, which assumes that LA geometry can be generalized from a single 2-dimensional plane; and (3) volume derived from the biplane method of discs. The correlation coefficient between the M-mode and biplane methods of determining LA volume was r = 0.76. The mean difference (+/-2 SDs) between these methods is -25 +/- 33 ml. The correlation coefficient between the single plane apical 4-chamber and biplane methods of determining LA volume is r = 0.97. The mean difference (+/-2 SDs) between these methods was -5.0 +/- 12 ml, indicating good agreement. The M-mode measure of the left atrium is an inaccurate representation of its size. Two-dimensional-derived LA volumes provide a more accurate measure of the true size of the left atrium and are more sensitive to changes in LA size. When an echocardiographic measure of LA size is made either in an individual patient or as a variable in a research study, the M-mode measure should be avoided.     

Evaluation of right atrial size in patients with atrial arrhythmias: comparison of 2D versus real time 3D echocardiography

Aim: This study compares different parameters of right atrial size evaluated by two-dimensional (2D) echocardiography with right atrial volume measured using three-dimensional echocardiography (3DE). Methods and Results: One hundred sixty-three consecutive patients with a history of atrial arrhythmias were studied by standard two-dimensional and by real time 3DE. Of these 142 (87%) recordings were of sufficient quality for interpretation of the right atrium by both imaging techniques. The following parameters of right atrial size were measured: apical four-chamber short-axis diameter (4CH short axis), apical four-chamber long axis diameter (4CH long axis), and apical four-chamber planimetry area. The 2D-derived right atrial volume was calculated by using the single plane area-length method (4CH area-length). The 2D parameters were then correlated with right atrial volume measured by real time 3DE. Linear regression analysis showed moderate correlation for four-chamber planimetry area (r = 0.72, P < 0.001) and 2D-derived volume calculation (r of 4CH single plane area-length RA volume = 0.70, P < 0.001). Diameters correlated clearly less well with 3DE volume (r of 4CH short axis = 0.61, 4CH long axis = 0.59, P < 0.001 respectively). Conclusion: Real time 3DE is highly feasible for right atrial volume determination. The results demonstrate that measurements of dimensions using 2D echocardiography may not accurately assess right atrial size. If 3DE is not available, apical 4CH planimetry area is a simple alternative that may be used for evaluating right atrial size in clinical practice. The 2D-derived right atrial volume by single plane area-length method was not better correlated with 3DE volume than four-chamber planimetry area.     

Approaches to determination of left ventricular volume and ejection fraction by real-time two-dimensional echocardiography.

Left ventricular volumes and ejection fraction were derived from real time two-dimensional echocardiographic images (2 DE) and single plane (RAO) left ventricular cineangiograms in a series of 50 patients. Prospective application of a series of 6 alternate algorithms showed that a modified Simpson's rule approach using mitral and papillary muscle cross sections and an apical four chamber view provided the best 2 DE - angiographic correlations: for end-diastolic volume r = 0.82, SEE = 39 ml; for end-systolic volume r = 0.90, SEE = 29 ml and for ejection fraction r = 0.80, SEE = 0.09. The large SEE for volume determination indicates that further refinements are necessary to predict left ventricular volumes adequately; however, ejection fraction can be derived with an accuracy which allows practical clinical decisions in patients with satisfactory 2 DE images.     

Right ventricular volumes and ejection fraction estimated by two-dimensional echocardiography

The right ventricular volumes and ejection fraction (RVEF) obtained from two-dimensional echocardiography and from right ventricular angiography were compared in 20 patients with congenital heart disease. Single plane area-length method of apical four-chamber view was used to estimate echocardiographic right ventricular volumes and single plane right anterior oblique projection was used to calculate angiographic right ventricular volumes. The results showed that right ventricular volumes estimated by echocardiography correlated highly with that calculated by angiography, the correlation coefficients of end-diastolic volume, end-systolic volume and stroke volume were 0.983, 0.976, 0.973 respectively. Echocardiographic RVEF also correlated strongly with angiographic RVEF (r = 0.992, P less than 0.001), and there were no significant difference between the two methods (P greater than 0.05). Conclusion: two-dimensional echocardiography can be used to accurately estimate right ventricular volumes and ejection fraction.     

Relationship between echocardiography, cardiac output, and abnormally contracting segments in patients with ischemic heart disease.

Twenty-four patients with proven coronary artery disease and abnormally-contracting segments were studied by both echocardiography and biplane angiographic techniques. Comparison was made between the left ventricular biplane angiographic volumes and those obtained from echocardiographic measurements which were calculated from cubed function and regression equaltion methods. The percent abnormally contracting segment (ACS) was obtained from biplane left ventricular angiography and was calculated from the diastolic and systolic anteroposterior and lateral angiocardiograms. The angiographic end-diastolic volume correlated with that calculated from the echocardiographic dimensions with an r value of 0.865 and SEE of +/- 22.64 ml. The angiographic end-systolic volume and echo end-systolic volume did not correlate as well, with an r = 0.7063. The difference in stroke volume predicted by the diastolic and systolic echocardiographic dimensions and the actual stroke volume determined by Fick technique was related to the percent abnormally contracting segment of the left ventricle (r = 0.8967). The percent ACS could be estimated from echo and Fick stroke volume measurements by the cube function and regression equations. Echo ventricular volume determinations were analyzed for the cube function method and the regression equations of Fortuin et al. and Teichholz and coworkers, with the method of Fortuin et al. producing the most sensitive relationship: % ACS = 0.32 (SVecho - SVFick) % + 8.9%. The correlation coefficient for the estimate was 0.8967 with a SEE of +/- 4.78%. In patients with coronary artery disease and abnormally contracting segments, echocardiography can provide reliable measurements of left ventricular end-diastolic volume but estimates of end-systolic volume are less accurate. If mitral regurgitation or a ventricular aneurysm can be excluded, the difference in echocardiographic and forward stroke volume by an independent method is related to the angiographic and forward stroke volume by an independent method is related to the angiographic abnormally contracting segment, and this relationship permits estimation of the size of the abnormally, contracting segment.     

Left atrial volumes assessed by three- and two-dimensional echocardiography compared to MRI estimates

Objectives: The aim of the present study was to establish the accuracy and reproducibility of left atrial volume measurements by three-dimensional (3D) echocardiography compared to 2D biplane and monoplane measurements. Background: No echocardiographic technique is generally accepted as optimal for estimation of left atrial size. Methods: Left atrial volumes of 18 unselected cardiac patients were obtained with magnetic resonance imaging (MRI) (volumes 145 ± 58ml). These volumes were compared with those obtained with different echocardiographic methods: a multiplane 3D method based on 90 images acquired by apical probe rotation, a simplified 3D method using only the three standard apical views, and 2D biplane and monoplane methods based on area-length, disc summation and spherical formulas. Results: The echocardiographic methods significantly underestimated maximum left atrial volumes as obtained by MRI by 14–37% (p < 0.001). Accuracy, expressed as 1 SD of individual estimates around this systematic underestimation, was 25 to 27% for all methods, except for the 2D 2-chamber monoplane method (37%). Interobserver coefficient of variation was between 14 and 20% for all methods (n.s.). Conclusion: All echocardiographic methods significantly underestimated left atrial volumes as obtained by MRI. A minor non-significant improvement in individual echocardiographic estimates by the 3D methods was obtained at the cost of more time consumption. In unselected patients ultrasound image quality precludes significant improvement of left atrial volume measurements by the applied 3D methods.     

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)     

Two-dimensional echocardiographic estimation of right ventricular ejection fraction in patients with coronary artery disease

Two-dimensional echocardiographic determination of right ventricular ejection fraction was compared with right ventricular ejection fraction obtained by first pass radionuclide angiography in 39 patients with coronary artery disease. Apical four chamber and two chamber right ventricular views were obtained in 34 (87%) of the 39 patients, while a subcostal four chamber view was obtained in 31 patients (80%). Right ventricular ejection fraction by two-dimensional echocardiography was calculated by the biplane area-length and Simpson's rule methods using two paired orthogonal views and utilizing a computerized light-pen method for tracing the right ventricular endocardium. A good correlation (r = 0.74 to 0.78) was found between radionuclide angiographic and two-dimensional echocardiographic right ventricular ejection fraction for each method used. Patients with acute inferior myocardial infarction had the lowest right ventricular ejection fraction by radionuclide angiography and two-dimensional echocardiography (p less than 0.05 compared with patients with right coronary artery obstruction and no infarction). There were no differences in right ventricular ejection fraction between patients with acute and old inferior myocardial infarction by both techniques. No correlation was found between left and right ventricular ejection fraction by radionuclide angiography (r = 0.16). It is concluded that 1) right ventricular ejection fraction by two-dimensional echocardiography correlates well with radionuclide angiographic measurements and can reliably evaluate right ventricular function in coronary artery disease, 2) patients with inferior myocardial infarction have reduced right ventricular ejection fraction, and 3) changes in left ventricular ejection fraction do not directly influence right ventricular function.     

Left ventricular volume calculations using a multiplanar transoesophageal echoprobe; in vitro validation and comparison with biplane angiography

BACKGROUND: Biplane angiographic and transthoracic echocardiographic volumecalculations have shown to be sufficiently reliable in synimetrichearts; however, they are unreliable in the presence of aneurysmaticdistortions. Multiplane transoesophageal echocardiography offersunobstructed cross-sectional views of the heart from one stabletransducer position with the potential of imaging irregularcavity forms more accurately. It was the purpose of this invitro study to compare the precision of multiplanar transoesophagealechocardiography to that of biplane angiography in determiningleft ventricular volumes, especially in aneurysmatic models. METHODS: Seven silicon rubber models of the left ventricle from post-mortemspecimens (four with aneurysms) were filled with 30 differentvolumes (range 153–256 ml, 197 ± 30 ml). Echocardiographiccross-sections (20° rotational steps) were obtained fromdifferent transducer positions, utilizing a multiplanar probewith a central rotational axis. Volumes were calculated usingthe discsummation method. For comparison the same volumes weredetermined by standard biplane angiography. The minimum numberof echo cross-sections necessary to optimize precision was analysedby calculating volumes for each increasing equidistant rotationalstep. RESULTS: Linear correlation between measured volume using a multiplanartransoesophageal echoprobe and true volume was high (r=0·97)and significantly better than for biplane angiography (r=0·88,P<0·001). Measurement bias and imprecision were alsosignificantly lower with multiplanar echocardiography than withbiplane angiography (3·9 ± 7·1% vs 11·1± 15·4%, and 2·0 ± 3·7% vs5·9 ± 8·3%; p<0·001). Precisionof biplane angiographic volume measurements was significantlyinfluenced by the presence of aneurysmatic distortions. Multiplanarecho volumes, however, were not influenced by left ventriculargeometry and transducer positions. Nine echo cross-sectionsprovided optimal precision. CONCLUSIONS: Three-dimensional echocardiographic volume calculations usinga multiplanar transoesophageal echoprobe and the disc-summationmethod provide precise measurements unaffected by left ventriculargeometry and transducer position in an in vitro setting. Standardbiplane angiography is significantly less precise.     

Is angiographic ventriculography necessary for the assessment of ischemic patients?

A total of 53 patients with a provisional diagnosis of ischemic heart disease and without any clinical evidence of valvular, congenital, or primary muscle heart disease were studied by echocardiography and biplane left ventricular cineangiography. For angiographic ejection fraction analysis, a program developed in our department for use on an Apple Macintosh computer interfaced to a digitizing tablet was employed. Echocardiographic outlines of systolic and diastolic images were traced with a digitizing system on the screen and ejection fractions were calculated by a program incorporated in the echo machine. Good echo windows allowing ejection fraction calculations were present in 35 patients. There was a good correlation between angiographic and echocardiographic ejection fraction (r = 0.7, SEE = 0.09), and wall motion assessment revealed no significant discrepancies between the two image modalities. The remaining 18 patients had poor echo windows, preventing accurate echocardiographic determination of the ejection fraction. However, limited assessment of left ventricular size and wall motion was possible in all patients and allowed the identification of those who had impaired left ventricular function as judged by angiography (angiographic ejection fraction < 35%). We conclude that even in patients with poor echo windows echocardiographic assessment of left ventricular function provides clinical information similar to angiography which should not be considered mandatory for the investigation of ordinary ischemic patients.     

Left ventricular volume and mass: Comparative study of two-dimensional echocardiography and ultrafast computed tomography

This study was undertaken to define the accuracy of two-dimensional echocardiography in the determination of left ventricular end-diastolic and end-systolic volumes, stroke volume, ejection fraction, and mass when compared to ultrafast cine computed tomography in the same 56 patients. Single-plane and biplane modified Simpson's rule, single-plane and biplane ellipsoidal formula, bullet formula (biplane only), and biapical Simpson's rule methods were utilized. Linear regression analysis showed the strongest correlation with the modified biplane Simpson's rule (mean r = 0.897). In valvular heart disease (n = 12) and dilated cardiomyopathy (n = 6), the mean correlation coefficients for all methods were high (r = 0.894 and 0.911, respectively). The mean correlation coefficient for all methods in patients with prior myocardial infarction (n = 25) was relatively poor (r = 0.643). Intraobserver and interobserver variabilities for all methods were low (r = 0.980 and 0.965, respectively). It is concluded that calculations of left ventricular volumes and mass by two-dimensional echocardiography are accurate and reproducible in patients with a global effect on the left ventricle and were less acceptable in patients with segmental (ischemic) left ventricular involvement. The best measurement technique is a modified biplane Simpson's rule.     

Rapid, semiautomated technique for estimating left ventricular volume

A new system for rapidly quantitating left ventricular volume using two-dimensional echocardiography is tested. This system relies on a microprocessor built into a sector scanner that immediately calculates the length, area, and volume of the chamber being imaged using the mathematical model of an ellipsoid of revolution. The calculations are made after the observer superimposes a smooth calibrated ellipse outline on the endocardium imaged with the sector scanner. We report our experience with this system in 50 patients with a variety of cardiac disorders and compare the left ventricular volumes measured with those obtained using cineangiography, M-mode, and more detailed light pen tracing techniques. Correlations between volumes measured with the elliptical calipers and angiography were good (r = 0.820, SEE +/- 38.8 ml) (n = 100), but not as good as that between light pen tracing of the echo images and angiography (r = 0.847, SEE +/- 27.8 ml) (n = 22). M-mode correlated less well with angiography (r = 0.789; SEE +/- 42.1 ml) (n = 90). We conclude that the calibrated ellipse system is rapid and simple to use, while its accuracy matches previous studies using two-dimensional echocardiography to quantitate left ventricular volume.     

Three echocardiographic methods in right ventricular function evaluation

We employed two-dimensional echocardiography for the assessment of right ventricular (RV) volumes and/or function in a series of 44 patients. The results of three different echocardiographic approaches were compared with the data obtained from single-plane RV angiography following ultrasound within a 7-day interval. Only the echocardiographic area length method with two orthogonal imaging planes employed (apical 4-chamber and subcostal projections) yielded the beneficial results. The correlations between echocardiographic and angiographic RV volume estimates were rather high (end-diastolic volume: r = 0.83, end-systolic volume: r = 0.82, stroke volume: r = 0.81) and satisfactory in ejection fraction (r = 0.75). Using the method mentioned, the differentiation of patients with an angiographic evidence of RV failure (echocardiographic ejection fraction less than 0.55) from those without it was possible with a sensitivity of 0.68 and a specificity of 0.82. Concerning the clinical impact of the presented study, we can recommend the technique in question as a screening procedure for the detection of changes in RV function exceeding 12% (95% confidence limits).     

Determination of left atrial area and volume by cross-sectional echocardiography in healthy infants and children

Part 1 of the study measured the end-systolic and end-diastolic left atrial (LA) areas and volumes in 30 children through sector echocardiography, and compared these values with those obtained with biplane angiocardiography. A strong correlation exists between the LA area in the frontal plane as determined by apical (r greater than 0.91) and subcostal (r greater than 0.98) echocardiography on the one hand and by angiocardiography on the other. However, there is a slight underestimation of the LA area by the apical 4-chamber view. LA volume as determined by subcostal sector echocardiography in the frontal and sagittal plane also correlated well with LA volume calculated with biplane angiocardiography (r greater than 0.97). Part 2 of the study determined LA areas and volumes in 74 healthy newborns and infants by echocardiography and related them to body weight and body surface area, thus obtaining normal values for this age group. The relation of the LA area and volume measurements in newborns and infants to body weight or surface area was best described by a linear function. The mean of the percentage of systolic-diastolic area diminution was 53 +/- 6% for the apical 4-chamber view and 50 +/- 4% for the subcostal 4-chamber view. LA ejection fraction determined by the subcostal biplane volume measurements was 62 +/- 7% (mean +/- standard deviation). These values were independent of body weight or surface area.     

Left ventricular volumes assessed by different new three-dimensional echocardiographic methods and ordinary biplane technique

Three-dimensional (3D) echocardiography may overcome the problems with inadequate accuracy and reproducibility of 2D volume measurements of the left ventricle. Aims: To establish the in vitro accuracy and reproducibility of two new methods for 3D echocardiographic volume determination as compared to biplane measurements. Methods: Validation of volume measurements by a multiplane 3D method was performed on asymmetric latex phantoms (n=8, true volumes 45-304 ml) using rotational acquisition of 90 image planes. Porcine agarose-filled asymmetrical left ventricles (n=7, true volumes 34 – 280 ml) were measured by the same multiplane 3D method based on images acquired by probe rotation axis perpendicular (A) and parallel (B) to the ventricular long axis. Ventricular volumes were also obtained by a simplified 3D system using only the three standard apical views (C) and by the ordinary biplane Simpsons method (D). Results: On latex phantoms systematic deviation from true volumes by multiplane 3D was less than 2%, and 95% variability of individual measurements from this mean was ± 4,9%. For accuracy on left ventricles, systematic bias was small with all the methods (<5%), but 95% variability of individual measurements was ±9,0%, 15.4%, 18.8% and 41.3% of true volumes for methods A-D respectively. Corresponding results in the same range were obtained for inter- and intraobserver variability. Conclusion: Individual in vitro volume estimates of left ventricles are of similar quality using apical multiplane or apical triplane 3D echocardiography. Both methods were superior to the ordinary apical biplane method, but inferior to multiplane 3D method with the probe directed perpendicular to the ventricular long axis.