volume, and ejection fraction are feasible in children.14 Most data come from the semiautomated method outlined above; the technique has proved highly repeatable The measurements of volume obtained by 3DE tend to underestimate those obtained using MRI, particularly in patients with congenital heart disease.15 Interestingly, estimates of ejection fraction are in closer agreement In addition to evaluating the feasibility of performing LV volumetrics, studies have addressed the use of resources, the learning curve and inter- and intraobserver reproducibility.16,17 Observers were able to obtain, in almost all cases, 3DE LV ejection fraction in less than 3 minutes, with the median time being less than 1.5 minutes They demonstrated a steep but negotiable learning curve with excellent interobserver and intraobserver reproducibility Left Ventricle Mass Studies in adults have validated the accuracy of 3DE for measuring LV mass.18 While studies in children have been limited in number and scope, excellent correlations have been shown between LV mass measured by 3DE and MRI.19 In young patients, when 3DE has been compared to M-mode derived estimation of LV mass, end-systolic 3DE LV mass has agreed more closely than has enddiastolic mass.17 One of the difficulties in using 3DE derived LV mass in children is the absence of normal values Left Ventricle Dyssynchrony The 3DE approach to measuring LV systolic dyssynchrony uses the LV model that is endorsed by the American Society of Echocardiography, which divides the ventricle into 16 segments.20 The software automatically measures the time taken for each subvolume to go from maximal (end-diastolic) volume to minimal (end-systolic) volume, and the standard deviation of these 16 time intervals The larger the standard deviation, the greater the implied degree of LV dyssynchrony To control for the wide range of heart rates in children, the time intervals are represented as a percentage of heart rate Consistent with adult data, the repeatability of this technique is highest when all 16 segments are included.17 The association between LV dysfunction and LV dyssynchrony in children has been explored.21 Normal children had 3DE LV dyssynchrony indexes that were below 3%; this has been corroborated in other studies.22 Among children with dilated cardiomyopathy, an ejection fraction below 35% was the rule among those with LV dyssynchrony In contrast, patients whose ejection fraction was higher than 35% had indexes of dyssynchrony that did not differ from the normal children who were studied Right Ventricular Volumetrics The accuracy of 3DE measurement of RV volume and ejection fraction has been the subject of several studies in patients with congenital heart disease due to the importance of volumetry in the clinical management of large cohorts of patients —notably those with repaired tetralogy of Fallot or a systemic RV There are major challenges in the application of such techniques to the RV due to its geometric shape and difficult anterior location, which impedes the entire volume being incorporated into the dataset The agreement among methods has been reviewed recently.9 Virtually all studies show a high correlation between 3DE and MRI methods This is of limited clinical value because in studies covering a wide range of ages and sizes, it is inevitable that smaller and younger patients will have lower volumes than larger and older patients In terms of agreement of methods in its stricter sense, semiautomated software designed for the RV still produces lower values of end-diastolic volume, end-systolic volume, and ejection fraction than MRI In tetralogy of Fallot, the difference is largest in the bigger ventricles, and in hypoplastic left heart syndrome, the difference is most pronounced in smaller patients.23 Methods utilizing “knowledge-based reconstruction” have closer agreement with MRI, but utilization of this technique is limited.24 The method of discs has the best agreement with MRI but remains time consuming and dependent on the appropriate analytic package.25,26 In current clinical practice, MRI-derived values and 3DE-derived RV volumes cannot be used interchangeably Recent work has coregistered MRI and echocardiographic data done in the same patient to identify the portions of the RV in which 3DE and MRI volumes differ the most.27 This type of approach is necessary to inform the development of software in the future to ensure improved agreement between these techniques The situation becomes even more complex in defects in which the ventricle approximates neither RV or LV morphology In such patients, the modeling of semiautomated analysis is usually invalid, and atlases of similar patient for a knowledge-based approach are not available In such cases, the method of discs approach would have to be used to avoid inappropriate geometric assumptions.28 Unfortunately, that approach is no longer available Nevertheless, as these tools become more widely available, user friendly, and accurate, we anticipate the development of new paradigms in the use of quantitative echocardiographic parameters as surrogate measures of outcome in clinical trials in patients with congenitally malformed hearts Three-Dimensional Color Flow Three-dimensional color flow Doppler information (superimposed onto 3D grayscale images) has been adopted into clinical practice, particularly to assess atrioventricular valves and the outflow tracts Tools for multiplanar reconstruction provide the ability to visualize and measure the areas of valvar regurgitant orifices at their narrowest point Thus the size, shape, and number of regurgitant jets can be assessed using 3DE This has translated into effective “mapping” of regions of atrioventricular valve regurgitation; this is integrated with visualization of valvar morphology to assist in the approach to valve repair.9,29 However, in pediatric and congenital practice, measurements of effective regurgitant orifice areas and vena contracta jets by 3DE have not been validated against other quantitative methods such as MRI This is true for both atrioventricular and arterial valves Additional challenges that are specific to childhood relate to indexation of the size of regions of regurgitation or stenosis to the size of the patient There is an urgent need for such validation work in an analogous manner to that which has been adopted to functional mitral valve regurgitation in adult patients.30 In recent years, the understanding of blood flow patterns within ventricles has progressed dramatically, including an understanding of the “vortex” of inflow to the ventricles.31 This vortex assists in minimizing dissipation of energy, preservation of blood flow momentum and redirection of blood from the inflow to the outlets of the heart A number of techniques have been used to assess this phenomenon including MRI and more recently 2DE tracking of the speckle pattern of the blood.32 3DE techniques using multiple different sonographic views have been applied to assessment of intracardiac vortices in a research setting and future applications may include 3D tracking of the blood pool.33 Such work is highly relevant to patients with congenital heart disease, where conservation of kinetic energy is crucial to several settings including the Fontan circulation and cardiomyopathies.34 ... with visualization of valvar morphology to assist in the approach to valve repair.9,29 However, in pediatric and congenital practice, measurements of effective regurgitant orifice areas and vena contracta jets by 3DE have not been