Quantitative three dimensional echocardiography in patients with pulmonary hypertension and compressed left ventricles: comparison with cross sectional echocardiography and magnetic resonance imaging

Clinical features of pulmonary arterial hypertension in patients receiving dasatinib

The prognosis of most leukemia patients treated with BCR-ABL tyrosine kinase inhibitors (TKIs) is favorable, and a more precise understanding of serious and potentially irreversible treatment-related toxicities is essential to properly inform treatment choice. Few cases of pulmonary arterial hypertension (PAH) have been reported in patients with leukemia treated with dasatinib, a second-generation BCR-ABL TKI. To better understand characteristics and outcomes of dasatinib-treated patients with PAH, all clinical cases of PAH confirmed by right-heart catheterization in the Bristol-Myers Squibb pharmacovigilance database (N = 41), including 22 previously unpublished cases, were examined for previous treatments for leukemia, patient characteristics, time to PAH onset, and outcomes. Our analysis shows that compared with PAH due to other etiologies, dasatinib-related PAH is atypical, in that it is associated with partial to complete reversibility upon treatment discontinuation. The incidence of dasatinib-related PAH appears to be low. Most PAH cases were observed in patients who had received prior treatments for leukemia. No specific patient attributes appear to be associated with an increased risk of developing PAH while receiving dasatinib. Symptoms of PAH in dasatinib-treated leukemia patients should prompt a thorough workup, including consideration of confirmatory right-heart catheterization. In cases of confirmed PAH, dasatinib should be discontinued.

Echocardiography in pediatric pulmonary hypertension

Pulmonary hypertension (PH) can be a rapidly progressive and fatal disease. Although right heart catheterization remains the gold standard in evaluation of PH, echocardiography remains an important tool in screening, diagnosing, evaluating, and following these patients. In this article, we will review the important echocardiographic parameters of the right heart in evaluating its anatomy, hemodynamic assessment, systolic, and diastolic function in children with PH.

Today's and tomorrow's imaging and circulating biomarkers for pulmonary arterial hypertension

The pathobiology of pulmonary arterial hypertension (PAH) involves a remodeling process in distal pulmonary arteries, as well as vasoconstriction and in situ thrombosis, leading to an increase in pulmonary vascular resistance, right heart failure and death. Its etiology may be idiopathic, but PAH is also frequently associated with underlying conditions such as connective tissue diseases. During the past decade, more than welcome novel therapies have been developed and are in development, including those increasingly targeting the remodeling process. These therapeutic options modestly increase the patients' long-term survival, now approaching 60% at 5 years. However, non-invasive tools for confirming PAH diagnosis, and assessing disease severity and response to therapy, are tragically lacking and would help to select the best treatment. After exclusion of other causes of pulmonary hypertension, a final diagnosis still relies on right heart catheterization, an invasive technique which cannot be repeated as often as an optimal follow-up might require. Similarly, other techniques and biomarkers used for assessing disease severity and response to treatment generally lack specificity and have significant limitations. In this review, imaging as well as current and future circulating biomarkers for diagnosis, prognosis, and follow-up are discussed.

Continuous and less invasive central hemodynamic monitoring by blood pressure waveform analysis

Blood pressure waveform analysis may permit continuous (i.e., automated) and less invasive (i.e., safer and simpler) central hemodynamic monitoring in the intensive care unit and other clinical settings without requiring any instrumentation beyond what is already in use or available. This practical approach has been a topic of intense investigation for decades and may garner even more interest henceforth due to the evolving demographics as well as recent trends in clinical hemodynamic monitoring. Here, we review techniques that have appeared in the literature for mathematically estimating clinically significant central hemodynamic variables, such as cardiac output, from different blood pressure waveforms. We begin by providing the rationale for pursuing such techniques. We then summarize earlier techniques and thereafter overview recent techniques by our collaborators and us in greater depth while pinpointing both their strengths and weaknesses. We conclude with suggestions for future research directions in the field and a description of some potential clinical applications of the techniques.

Computed axial tomography evidence of left atrial enlargement: a predictor of elevated pulmonary capillary wedge pressure in pulmonary hypertension

BACKGROUND

One of the commonest causes of pulmonary hypertension (PH) is left heart dysfunction associated with elevated pulmonary capillary wedge pressure (PCWP). In contrast, the pathology of pulmonary arterial hypertension (PAH) originates in the pulmonary vascular bed. Accurate diagnosis of PAH requires right heart catheterization (RHC) with normal PCWP. This study examines the role of computed tomography of the chest (CT chest) in evaluating left atrial (LA) size as an indicator of elevated PCWP in patients undergoing PH evaluation.

METHODS

CT chest and RHC data were reviewed in 37 subjects at the Baylor PH Center. Both subjective estimates and objective measurements of left atrial size from the CT chest were recorded separately by 3 investigators. Patients were categorized as Group I (small-normal LA) and Group II (large LA) and RHC results compared.The objective and subjective measurements were compared by receiver operator characteristic (ROC).

RESULTS

The mean PCWP was 12 +/- 6 mmHg in Group I and 21 +/- 7 mmHg in Group II (P = 0.001). The estimated LA area was 19.4 +/- 4.9 cm(2) in Group I and 39.9 +/- 7.6 cm(2) in Group II (mean +/- SD; P < 0.001). The estimated LA area, corrected for the chest wall length, was 0.78 +/- 0.19 cm(2) and 1.65 +/- 0.26 cm(2) in Groups I and II, respectively (P < 0.001). Significant correlations were found between uncorrected PCWP and LA area (R = 0.45, P = 0.005), corrected PCWP and LA area (R = 0.47, P = 0.003), and the subjective observer impression of LA enlargement and measured PCWP (R = 0.51, P = 0.001).

CONCLUSION

In this pilot study, enlarged LA area on the CT chest was associated with an elevated PCWP on RHC. For patients undergoing PH evaluation, increased LA area on CT chest could suggest left heart dysfunction in patients as a possible cause of PH.

Diagnostic strategies for acute presentation of pulmonary hypertension in children: particular focus on use of echocardiography, cardiac catheterization, magnetic resonance imaging, chest computed tomography, and lung biopsy

Determining the etiology of pediatric pulmonary hypertension is essential to appropriate management. Assessment of the patient requires complete history and physical examination as well as the use of investigative modalities including echocardiography, cardiac catheterization, cardiac magnetic resonance imaging (MRI), chest computed tomography, and lung biopsy. This review summarizes recommendations for diagnostic work-up and includes a clinical algorithm for evaluation of the patient with acute pulmonary hypertension in the pediatric intensive care unit.

Assessment of mitral valve volume by quantitative three-dimensional echocardiography in patients with rheumatic mitral valve stenosis

BACKGROUND

Thickening of mitral leaflets in rheumatic mitral valve stenosis is well described in necropsy studies; however, volume computation of the thickening mitral leaflets has not been attempted. 4trial fibrillation is one of the complications of rheumatic mitral stenosis. Quantitative assessment of thickened mitral valve and its relation to clinical complications is clinically desirable.

HYPOTHESIS

The study was undertaken to compare measurement of mitral valve volume in normal subjects and in patients with rheumatic mitral valve stenosis.

METHODS

An HP Sonos 2500 echocardiographic system with 5 MHz multiplane transesophageal transducer was used for data acquisition, and TomTec Echoscan computer setup was used to off-line volume computation. Study subjects included 10 normal subjects (mean age 44.8 years) and 36 patients with rheumatic mitral valve stenosis (22 female, 14 male) with an age range of 25 to 69 years (mean age 47 +/- 9.6 years). Mitral valve volumes were compared between the normal subjects and patients with mitral valve stenosis, and further comparison was made between the sinus rhythm (SR) and atrial fibrillation (AF) groups in patients with mitral valve stenosis. In all study subjects, the mitral valve area (MVA) was determined by two-dimensional echocardiography.

RESULTS

Quantitative three-dimensional (3-D) echocardiography showed that mitral valve volume was significantly larger in patients with mitral valve stenosis than in normal subjects (9.0 +/- 2.2 and 4.5 +/- 0.7 ml, respectively, p < 0.001). When patients with mitral valve stenosis were divided into the SR and AF groups, mitral valve volume was found to be significantly larger in the AF group than in the SR group (9.76 +/- 2.2 ml. and 7.72 +/- 1.5 ml, respectively, p < 0.01) and patients in the AF group tended to be older (p < 0.05) with larger left atrial diameter (LAD) (p < 0.01). However, MVA between the two groups showed no statistical significance (1.1 +/- 0.43 and 1.0 +/- 0.34 cm2, respectively, p > 0.2). When the study subjects were divided into two groups (< 50 and > or = 50 years) according to age, the comparison of mitral valve volume between these two groups (9.37 +/- 2.18 and 8.56 +/- 2.14 ml, p > 0.2) showed no statistical significance.

CONCLUSIONS

Quantitative 3-D echocardiography can be applied for the measurement of mitral valve volume in vivo. Patients with rheumatic mitral valve stenosis with atrial fibrillation have a propensity to have a larger mitral valve volume and are older than the patients with sinus rhythm; however, the age per se does not seem to be a cause for larger mitral valve volume.

Right heart function and haemodynamics in pulmonary hypertension

The primary challenge in the care of the patient with advanced pulmonary arterial hypertension (PAH) is right ventricular dysfunction with concomitant right heart failure. Right heart function is closely tied to survival in this disease, and there is a growing interest in the study of this unique structure. While echocardiography and cardiac magnetic resonance (CMR) have augmented our ability to image the right ventricle (RV), the primary means of assessing right heart function remains right heart catheterisation. Several of the currently available treatments for PAH have been shown to have effects on the RV, not just the pulmonary vasculature, and, in future, therapies aimed at optimizing right ventricular function may allow better outcomes in this challenging disease. New directions in right ventricular assessment including measurement of pulmonary vascular impedance and more widespread availability of CMR may allow greater knowledge about this little studied, yet highly important, right side of the heart.

Imaging of the heart in pulmonary hypertension

Pulmonary hypertension (PH) is a disease of the pulmonary arteries resulting in a progressive increase in pulmonary vascular resistance, ultimately leading to right ventricular failure and death. It is a rare disease with a poor prognosis. The functional capacity of the right ventricle (RV) is a major prognostic determinant in PH. Our understanding of RV performance in PH has been hindered by the lack of techniques that give a reliable picture of right ventricular morphology and function. There have been recent major advances in our understanding of the mechanism of disease development, in the diagnostic process and in the treatment of PH. There are now three classes of medications that are effective in the treatment of PH: prostanoids, endothelin receptor antagonists and phosphodiesterase-5 inhibitors. Therapeutic advances in the management of PH have reinforced the requirement for non-invasive, accurate and reproducible methods of assessment to act as 'end-points' to measure the effects of treatment. It is our opinion that the most useful 'end-point' would be one that evaluates right heart morphology and function. We introduce and discuss the techniques currently used to image the heart in patients with PH. Imaging modalities discussed include echocardiography, radionuclide ventriculography, cardiac computed tomography and cardiac magnetic resonance (CMR) imaging focusing on the rapidly evolving technique of CMR imaging.

Three-dimensional echocardiography: research toy or clinical tool?

Conventional 2D echocardiography is an excellent qualitative imaging method, but its use for quantitation is limited by test-retest reproducibility of image planes. The increasing sophistication of medical treatments for left ventricular dysfunction, hypertension and valvular heart disease has created the need for accurate and reproducible measurements of chamber dimensions. Similarly, improvements in valve repair and catheter-based interventions for valve lesions and septal defects have created the need for better visualisation of cardiac structures. The use of 31) echocardiography may decrease variability both in the quality and interpretation of complex pathology among investigators. Three-dimensional echocardiography is achieved by using a 3D spatial registration device with a conventional 21) scanner, or by using a high-speed, phased-array real-time scanner. The latter are still developmental, so that the technique currently requires use of a 21) scanner, combined with a 31) spatial coordinate system, which may be external or internal to the scanning transducer. An external system permits data acquired from several cardiac windows to be integrated and reconstructed. Image reconstruction is performed using a wire-frame model or surface rendering. Wire-frame models are formed by manual or automatic connection of boundary data points; this approach uses fewer data points than rendering, can be rapidly processed and is sufficient for quantitative analysis. Surface-rendering uses lighting and shading applied to a wire-frame model to produce a realistic 31) display, which may be useful for surgical planning and increasing understanding of anatomic relations. Three-dimensional echocardiography yields more accurate measurements of ventricular volume and function, as well as new measurements such as infarct area. With increased reproducibility and reliability, 3D echocardiography may well prove to be the essential tool required for the serial follow up of left ventricular mass and volume.

Segmentation of real-time three-dimensional ultrasound for quantification of ventricular function: a clinical study on right and left ventricles

Among screening modalities, echocardiography is the fastest, least expensive and least invasive method for imaging the heart. A new generation of three-dimensional (3-D) ultrasound (US) technology has been developed with real-time 3-D (RT3-D) matrix phased-array transducers. These transducers allow interactive 3-D visualization of cardiac anatomy and fast ventricular volume estimation without tomographic interpolation as required with earlier 3-D US acquisition systems. However, real-time acquisition speed is performed at the cost of decreasing spatial resolution, leading to echocardiographic data with poor definition of anatomical structures and high levels of speckle noise. The poor quality of the US signal has limited the acceptance of RT3-D US technology in clinical practice, despite the wealth of information acquired by this system, far greater than with any other existing echocardiography screening modality. We present, in this work, a clinical study for segmentation of right and left ventricular volumes using RT3-D US. A preprocessing of the volumetric data sets was performed using spatiotemporal brushlet denoising, as presented in previous articles Two deformable-model segmentation methods were implemented in 2-D using a parametric formulation and in 3-D using an implicit formulation with a level set implementation for extraction of endocardial surfaces on denoised RT3-D US data. A complete and rigorous validation of the segmentation methods was carried out for quantification of left and right ventricular volumes and ejection fraction, including comparison of measurements with cardiac magnetic resonance imaging as the reference. Results for volume and ejection fraction measurements report good performance of quantification of cardiac function on RT3-D data compared with magnetic resonance imaging with better performance of semiautomatic segmentation methods than with manual tracing on the US data.

Fetal ventricular mass determination on three-dimensional echocardiography: studies in normal fetuses and validation experiments

BACKGROUND

Estimation of ventricular volume and mass is important for baseline and serial evaluation of fetuses with normal or abnormal hearts. Direct measurement of chamber wall volumes and mass can be made without geometric assumptions by 3D fetal echocardiography. Our goals were to determine the feasibility of using fast nongated 3D echocardiography for fetal volumetric and mass assessments, to validate the accuracy of the ultrasound system and the measurement technique, and if satisfactory, to develop normal values for fetal ventricular mass during the second and third trimesters.

METHODS AND RESULTS

This was a prospective outpatient study of 90 consecutive normal pregnancies during routine obstetric services at Oregon Health & Science University (Portland). Optimized 3D volumes of the fetal thorax and cardiac chambers were rapidly acquired and later analyzed for right and left ventricular mass by radial summation technique from manual epicardial and endocardial traces. Experiments to validate the ultrasound system and measurement technique were performed with modified small balloon models and in vivo and ex vivo small animal experiments. Our study established the feasibility of fetal ventricular mass measurements with 3D ultrasound technology and developed normal values for right and left ventricular mass from 15 weeks' gestation to term.

CONCLUSIONS

Nongated fast 3D fetal echocardiography is an acceptable modality for determination of cardiac chamber wall volume and mass with good accuracy and acceptable interobserver variability. The method should be especially valuable as an objective serial measurement in clinical fetal studies with structurally or functionally abnormal hearts.

Noncompressibility of myocardium during systole with freehand three-dimensional echocardiography

BACKGROUND

Measures of ventricular performance, such as the ejection fraction, assume that myocardium is noncompressible and does not change volume significantly from end diastole to end systole. Although this principle is widely accepted as true, little data exist in the literature to support it. Freehand 3-dimensional (3D) echocardiography has previously been shown to be highly accurate for measurement of myocardial mass and volume. Therefore, we hypothesized that it has sufficient accuracy to test the validity of this assumption. We measured myocardial volume at end diastole and end systole in 2 groups of subjects with hypertrophy.

METHODS

Forty-one healthy young adult athletes and 17 adult patients with hypertension, hypertrophy, normal ejection fraction, and heart failure symptoms underwent examination with freehand 3D echocardiography. Endocardial and epicardial surfaces at end diastole and end systole were reconstructed, and their volumes were computed. From these surface volumes, myocardial volume at end diastole and end systole and epicardial stroke volume and endocardial stroke volume were calculated. These volumes were compared with the 2 sample paired t test.

RESULTS

Myocardial volume was constant from diastole to systole (174.7 +/- 45.3 mL versus 174.6 +/- 45.8 mL; P = not significant), and endocardial and epicardial stroke volumes were identical (76.0 +/- 17.4 mL versus 76.0 +/- 17.1 mL; P = not significant). The average absolute difference between the end-diastolic and end-systolic myocardial volumes was 1.9 mL, or less than 1.1% of end-diastolic volume.

CONCLUSION

Myocardial volume measured with freehand 3D echocardiography does not change significantly during systole. Myocardial volume may be considered noncompressible for purposes of measurement of ventricular function with freehand 3D echocardiography. Comparison of end-diastolic and end-systolic myocardial volumes may be used for quality assurance in performing 3D reconstructions.

Myocardial contraction fraction: a volumetric index of myocardial shortening by freehand three-dimensional echocardiography

OBJECTIVES

This study sought to evaluate myocardial contraction fraction (MCF) as an index of myocardial shortening by comparison to conventional shortening indices in patients with hypertensive hypertrophy, athletes with physiologic hypertrophy and sedentary normal adult subjects.

BACKGROUND

A significant percentage of patients with hypertensive hypertrophy have "normal" or "preserved" left ventricular (LV) systolic function by conventional echocardiographic measures whereas their systolic function is depressed when measured by the two-dimensional echocardiographic mid-wall shortening fraction (MWSF). A three-dimensional echocardiographic measure of myocardial shortening analogous to MWSF has been lacking. We describe a volumetric measure of myocardial shortening, the MCF, as the ratio of stroke volume (SV) to myocardial volume (MV), and hypothesize that it may be useful to compare myocardial performance in patients with different degrees and types of hypertrophy.

METHODS

We compared the MCF using freehand three-dimensional echocardiographic reconstruction of the LV to conventional measures of LV function (ejection fraction [EF], endocardial shortening fraction [SF] and MWSF) in subjects with pathologic hypertensive hypertrophy, heart failure symptoms and preserved EF (n = 17), athletes with physiologic hypertrophy (n = 41) and normal sedentary adults (n = 80).

RESULTS

The EF was in the normal range for all three groups. The MCF was lower in hypertensive hypertrophy compared with normal subjects (0.33 +/- 0.05 vs. 0.44 +/- 0.07, p < 0.01). It also successfully differentiated physiologic hypertrophy from normal subjects (0.50 +/- 0.05 vs. 0.44 +/- 0.07, p < 0.01). The endocardial SF did not distinguish athletes from normal subjects and the MWSF did not distinguish hypertensive from physiologic hypertrophy.

CONCLUSIONS

The MCF, a volumetric measure of myocardial shortening, demonstrates that myocardial shortening is decreased in hypertensive hypertrophy and increased in physiologic hypertrophy. The MCF may be useful in assessing differences in myocardial performance in patients with similar degrees of hypertrophy.

Measurement of left ventricular dimensions and function in patients with dilated cardiomyopathy

Studies on medical therapy in heart failure are focused on changes of left ventricular (LV) dimensions and function. These changes may be small, requiring a large study group. We measured LV parameters (LV volumes, LV ejection fraction (LV-EF), and left ventricular mass (LVM)) with two-dimensional echocardiography (2D-echo) and magnetic resonance imaging (MRI) in 50 patients. Based on the difference between the measurements, we determined the variance of the results and calculated the sample sizes needed to detect changes of baseline values. For the calculated and measured parameters we found significant differences between the two techniques: LV-EF and LVM were higher in 2D-echo, and LV dimensions were comparable. The sample size to detect relevant changes from baseline with MRI was significantly (P < 0.01) smaller than in 2D-echo. We conclude that MRI is superior in clinical studies on left ventricular dimensional and functional changes, since measurements are more reproducible and the required sample size is substantially smaller, thereby reducing costs.

MR imaging of adult patients with congenital heart disease

Although the incidence of congenital heart disease remains constant among newborns, improved medical and surgical techniques have dramatically prolonged life expectancy and produced a new, growing group of patients harboring these lesions: adults with congenital heart disease. Conventional imaging techniques in these patients may be limited because of patient size, chest configuration, or poor ventricular function. MR imaging provides a noninvasive means of directly demonstrating their developmental abnormalities and the sequelae of pathophysiologic changes caused by these lesions. Combined use of spin echo and gradient reversal echo acquisition techniques allows complete evaluation of cardiac morphology and function in these patients. An new medical and surgical therapies prolong the lives of these patients, the role of MR imaging for physiologic assessment and surgical planning will expand further.

Tomographic three-dimensional echocardiographic determination of chamber size and systolic function in patients with left ventricular aneurysm: comparison to magnetic resonance imaging, cineventriculography, and two-dimensional echocardiography

BACKGROUND

Two-dimensional (2D) echocardiographic approaches based on geometric assumptions face the greatest limitations and inaccuracies in patients with left ventricular (LV) aneurysms. Three-dimensional (3D) echocardiographic techniques can potentially overcome these limitations; to date, however, although tested in experimental models of aneurysms, they have not been applied to a series of patients with such distortion. The purpose of this study was therefore to validate the clinical application of tomographic 3D echocardiography (3DE) by the routine transthoracic approach to determine LV chamber size and systolic function without geometric assumptions in patients with LV aneurysms.

METHODS AND RESULTS

In 23 patients with chronic stable LV aneurysms, LV end-systolic and end-diastolic volumes (LVEDV, LVESV) and ejection fraction (LVEF) by tomographic 3DE were compared with results from 3D magnetic resonance tomography (3DMRT) as an independent reference as well as with the conventional techniques of single plane and biplane 2D echocardiography and biplane cineventriculography. Dynamic 3DE image data sets were obtained from a transthoracic apical view with the use of a rotating probe with acquisition gated to control for ECG and respiration (Echoscan, TomTec). Volumes were calculated from the 3D data sets by summating the volumes of multiple parallel disks. 3DE results correlated and agreed well with those by 3DMRT, with better correlation and agreement than provided by other techniques for LVEDV (3DE: r=.97, SEE=14.7 mL, SD of differences from 3DMRT=14.5 mL; other techniques: r=.84 to .93, SEE=30.7 to 41.6 mL [P<.001 versus 3DE by F test], SD of differences=31.5 to 40.7 mL [P<.001 versus 3DE by F test]). The same also pertained to LVESV (3DE: r=.97, SEE=12.4 mL, SD of differences=12.9 mL; other techniques: r=.81 to .90, SEE=24.7 to 37.2 mL [P<.001], SD of differences=27.6 to 36.8 mL [P<.005]) and LVEF (3DE: r=.74, SEE=5.6%, SD of differences=6.7%; other techniques: r=.14 to .59, SEE=9.5% to 10.1% [P<.01], SD of differences=9.5% to 12.6% [P<.05]). Compared with 3DMRT, 3DE was less time consuming and patient discomfort was less.

CONCLUSIONS

Tomographic 3DE is an accurate noninvasive technique for calculating LV volumes and systolic function in patients with LV aneurysm. Unlike current 2D methods, tomographic 3DE requires no geometric assumptions that limit accuracy.

Hemodynamic evaluation of the heart with a nonfluoroscopic electromechanical mapping technique

BACKGROUND

Clinical cardiac volumetric measurement techniques are essential for assessing cardiac performance but produce significant inaccuracies in extrapolation of the volume of a three-dimensional (3D) object from two-dimensional images and lack the ability to associate cardiac electrical and mechanical activities. In this study, we tested the accuracy of cardiac volumetric measurements using a new catheter-based system.

METHODS AND RESULTS

The system uses magnetic technology to accurately locate a special catheter at a frequency of 125 Hz and is currently used in the field of electrophysiology, in which activation maps are superimposed on the 3D geometry of the cardiac chamber. The mapping procedure is based on sequentially acquiring the location of the tip and local electrogram while in contact with the endocardium. The 3D geometry of the chamber is reconstructed in real time, and its volume could be calculated at every time step (8 ms). The volumetric measurements of the system were found to be highly accurate for simple phantoms (mean+/-SEM deviation, 2.3+/-1.1%), left ventricular casts (9.6+/-1.3%), and a dynamic test jig. In addition, left ventricular volumes of 12 swine were measured. Intraobserver and interobserver variabilities were found to be minimal (ejection fraction, 6.5+/-1.9% and 7.1+/-2.0%; stroke volume, 4.5+/-1.0% and 11.3+/-2.4%). Comparison with the thermodilution method for measuring stroke volume showed an average deviation of 8.1+/-2.2%. Typical pressure-volume loops were also obtained.

CONCLUSIONS

The new mapping image provides, for the first time, simultaneous information regarding cardiac mechanics, hemodynamics, and electrical properties. Furthermore, all this information is achieved without the use of fluoroscopy, contrast medium, or complicated image processing.

Comparison of three-dimensional echocardiographic assessment of volume, mass, and function in children with functionally single left ventricles with two-dimensional echocardiography and magnetic resonance imaging

Diminished systolic function or inappropriate hypertrophy are considered risk factors for outcome following the Fontan procedure. These parameters are difficult to assess in univentricular hearts that do not conform to the uniform shapes prescribed by conventional 2-dimensional imaging volume algorithms. Three-dimensional echocardiography requires no geometric assumptions and has been validated in both normal and distorted left ventricles. To assess the feasibility and accuracy of this technique in patients with univentricular hearts, we compared 2- and 3-dimensional echocardiographic estimates of ventricular volume, ejection fraction, and mass in patients with functionally single left ventricles with results obtained by magnetic resonance imaging (MRI). Twelve patients with functionally single left ventricles (6 months to 22 years) underwent examination by all 3 modalities. Correlation and agreement with MRI were calculated for volumes, ejection fraction, and mass. Three-dimensional echocardiographic comparison with MRI yielded a bias of 3.4 +/- 5.5 ml and 14.2 +/- 8.3 ml for systolic and diastolic volumes, respectively. Agreement analysis for mass showed a bias of 5.8 +/- 8.4 grams. Two-dimensional echocardiography showed less agreement for both volumes and mass (bias of -2.9 +/- 8.1, 2.9 +/- 10.4 ml and -8.3 +/- 12.0 g for volume and mass, respectively, p >0.05). Ejection fraction by 3-dimensional echocardiography showed significantly closer agreement with MRI (bias of 4.4 +/- 5.3%) than 2-dimensional echocardiography (bias of 8.5 +/- 10.3%, p = 0.04). Thus, 3-dimensional echocardiography provides estimates of ventricular volumes, ejection fraction, and mass that are comparable to MRI in this select group of patients with single ventricles of left ventricular morphology.