Heleen B. van der Zwaan

Clinical value of real-time three-dimensional echocardiography for right ventricular quantification in congenital heart disease: validation with cardiac magnetic resonance imaging.

BACKGROUND The objective of this study was to test the feasibility, accuracy, and reproducibility of the assessment of right ventricular (RV) volumes and ejection fraction (EF) using real-time three-dimensional echocardiographic (RT3DE) imaging in patients with congenital heart disease (CHD), using cardiac magnetic resonance (CMR) as a reference. METHODS RT3DE data sets and short-axis cine CMR images were obtained in 62 consecutive patients (mean age, 26.9 +/- 10.4 years; 65% men) with various CHDs. RV volumetric quantification was done using semiautomated 3-dimensional border detection for RT3DE images and manual tracing of contours in multiple slices for CMR images. RESULTS Adequate RV RT3DE data sets could be analyzed in 50 of 62 patients (81%). The time needed for RV acquisition and analysis was less for RT3DE imaging than for CMR (P < .001). Compared with CMR, RT3DE imaging underestimated RV end-diastolic and end-systolic volumes and EF by 34 +/- 65 mL, 11 +/- 55 mL, and 4 +/- 13% (P < .05) with 95% limits of agreement of +/-131 mL, +/-109 mL, and +/-27%, as shown by Bland-Altman analyses, with highly significant correlations (r = 0.93, r = 0.91, and r = 0.74, respectively, P < .001). Interobserver variability was 1 +/- 15%, 6 +/- 17%, and 8 +/- 13% for end-diastolic and end-systolic volumes and EF, respectively. CONCLUSION In the majority of unselected patients with complex CHD, RT3DE imaging provides a fast and reproducible assessment of RV volumes and EF with fair to good accuracy compared with CMR reference data when using current commercially available hardware and software. Further studies are warranted to confirm our data in similar and other patient populations to establish its use in clinical practice.

Right ventricular quantification in clinical practice: two-dimensional vs. three-dimensional echocardiography compared with cardiac magnetic resonance imaging.

AIMS To establish the additional value of three-dimensional echocardiography (3D echo) for assessment of right ventricular (RV) size and function in patients with congenital heart disease (CHD) in everyday clinical practice, the accuracy and reproducibility of 3D echo were compared with conventional two-dimensional echocardiography (2D echo) and cardiac magnetic resonance (CMR) imaging as reference. METHODS AND RESULTS Patients with CHD and primarily affected right ventricles (n = 62), patients with CHD and primarily affected left ventricles (LV group, n = 27), and healthy controls (n = 31) were studied. 2D echo-, 3D echo- and CMR data sets were obtained. Moderate correlations were found between RV dimensions by 2D echo and CMR-derived RV end-diastolic volumes (r = 0.32-0.77). The correlations between RV volumes obtained by 3D echo and CMR imaging were better (r = 0.71-0.97) than the 2D echo-derived correlations (P < 0.001). Only the 2D echo-derived RV inlet diameter correlated better in healthy controls than in the RV group. Receiver operating characteristic curve analysis revealed that 3D echo-derived end-diastolic volume best identified RV dysfunction (sensitivity 95% and specificity 100%). The 3D echo-derived measurements were as reproducible as the 2D echo-derived measurements (n = 37, coefficients of variation ranging from 5 to 19%), with tricuspid annular plane systolic excursion being the most reproducible measurement (coefficient of variation of 6%). CONCLUSION 3D echo improved quantitative RV size and function assessment compared with 2D echo in patients as well as in healthy controls. Everyday clinical use of 3D echo for RV assessment can be reality with the currently available software and provides incremental benefit in assessment of the right ventricle.

Accuracy and Reproducibility of Quantitation of Left Ventricular Function by Real-Time Three-Dimensional Echocardiography Versus Cardiac Magnetic Resonance

The aim of this study was to investigate the accuracy and reproducibility of the quantification of left ventricular (LV) function by real-time 3-dimensional echocardiography (RT3DE) using current state-of-the-art hardware and software. Compared with cardiac magnetic resonance (CMR), previous generations of hardware and software for RT3DE significantly underestimated LV volumes partly because of inherent factors such as limited spatial and temporal resolution. Also, RT3DE volumes were compared with short-axis CMR data, whereas a combined short-axis and long-axis analysis is known to be superior. Twenty-four subjects (mean age 51 +/- 12 years, 17 men) in sinus rhythm and with good to excellent 2-dimensional image quality underwent RT3DE and CMR within 1 day. The acquisition of RT3DE data was done with current state-of-the-art hardware and software. Two blinded experts performed off-line LV volume analysis. Global LV volumes were determined from semiautomated border detection on the basis of endocardial speckle tracking with biplane projections using QLAB version 6.0. Volumes derived by magnetic resonance imaging were quantified from combined short-axis and long-axis series. The volume-rate on RT3DE was 33 +/- 8 Hz (range 19 to 42). Excellent correlations were found (R2 > or = 0.97) between CMR and RT3DE for global LV end-diastolic volume, LV end-systolic volume, the LV ejection fraction, and LV phase volumes (24 phases/cardiac cycle). Bland-Altman analyses showed mean differences of -7.1 ml, -4.2 ml, 0.2%, and -5.8 ml and 95% limits of agreement of +/-19.7 ml, +/-8.3 ml, +/-6.2%, and +/-15.4 ml for global LV end-diastolic volume, LV end-systolic volume, the LV ejection fraction, and LV phase volumes, respectively. Interobserver variability was 5.2% for global LV end-diastolic volume, 6.4% for LV end-systolic volume, and 7.6% for the LV ejection fraction. In conclusion, in patients with good acoustic windows, RT3DE using state-of-the-art technology provides accurate and reproducible measurements of global LV volumes, LV volume changes over time, and the LV ejection fraction.

Quantification of Left Ventricular Systolic Dyssynchrony by Real-Time Three-Dimensional Echocardiography

OBJECTIVE To assess real-time 3-dimensional echocardiography (RT3DE)-derived left ventricular (LV) systolic dyssynchrony parameters: (1) normal values, (2) characteristics in patients with heart failure (HF) and a wide or narrow QRS complex, (3) interobserver and intraobserver variability with current state of the art RT3DE hardware and software technology, and (4) incremental value in patients with HF who receive cardiac resynchronization therapy (CRT). METHODS The study involved 84 patients with HF (mean age 54 +/- 15 years, 50 men) and 60 healthy volunteers (mean age 41 +/- 15 years, 36 men). Semiautomated LV endocardial border tracking was used to calculate regional time-to-minimum systolic volume and to generate parametric maps and the systolic dyssynchrony index (SDI), defined as the standard deviation of time-to-minimum systolic volume of the 16 LV segments expressed in percentage of R-R duration. RESULTS The volume rate of the RT3DE datasets in patients with HF was 31 +/- 9 Hz (range 15-42 Hz). The normal value of the SDI was 4.1% +/- 2.2% (range <1.0%-8.9%). Patients with HF had a larger SDI (13.4% +/- 8.1%, P < .001). There was only a weak correlation (r2 = 0.07, P < .05) between the QRS duration and the SDI. Interobserver interclass correlation and variability of the SDI depended on image quality (good: 0.993 and 9%, moderate: 0.907 and 16%, respectively). Interobserver agreement for the identification of the most delayed LV segment depended on image quality (good: 90%, moderate: 76%). Thirty-nine patients underwent CRT. At the 12-month follow-up, LV volumetric responders had a significant reduction in the SDI (16.3% +/- 3.3% to 7.7% +/- 2.4%, P < .001). CONCLUSION With state of the art technology, RT3DE allows reproducible assessment of LV systolic dyssynchrony, which may be useful to identify potential responders to CRT.

Influence of cardiac shape on left ventricular twist

The dynamic interaction between subendocardial and subepicardial fibre helices in the left ventricle (LV) leads to a twisting deformation, which has an important role in LV function. This study sought to assess the influence of cardiac shape on LV twist in the normal and dilated human heart. The study comprised 45 dilated cardiomyopathy (DCM) patients and 60 for age- and gender-matched healthy volunteers. Speckle tracking echocardiography was used to determine basal and apical LV peak systolic rotation (Rot(max)) and instantaneous LV peak systolic twist (Twist(max)). LV sphericity index was calculated by dividing the LV maximal long-axis internal dimension by the maximal short-axis internal dimension at end-diastole. A parabolic relation between the sphericity index and apical Rot(max) or Twist(max) was identified in the total study population (R(2) = 0.56 and R(2) = 0.54, respectively; both P < 0.001) and healthy volunteers (R(2) = 0.39 and R(2) = 0.25, respectively; both P < 0.001), whereas these relations were linear in DCM patients (R(2) = 0.40 and R(2) = 0.43, respectively; both P < 0.001). In a multivariate analysis, LV sphericity index was the strongest independent predictor of apical Rot(max) and Twist(max). In conclusion, LV apical rotation and twist are significantly influenced by LV configuration. Taking the important function of LV twist into account, this finding highlights the vital influence of cardiac shape on LV systolic function.

Feasibility and reproducibility of left ventricular rotation parameters measured by speckle tracking echocardiography

AIMS This study sought to find the most robust method for left ventricular (LV) rotation measurement by speckle tracking echocardiography (STE) with the new QLAB Advanced Quantification Software (version 6.0, Philips, Best, The Netherlands). METHODS AND RESULTS The study population consisted of 40 non-selected patients (mean age 48 +/- 18 year, 20 men) and 50 non-selected healthy volunteers (mean age 34 +/- 12 year, 21 men). Feasibility and intra-observer reproducibility of the measurement of LV rotation parameters by STE were assessed for two different methods (Method A: six tracking points placed mid-myocardial and Method B: six tracking points placed endocardial and epicardial forming six myocardial segments). Subsequently, inter-observer and temporal reproducibility of the most robust method were assessed. Complete LV rotation assessment was more feasible with Method A (60 out of 90 subjects, 67% vs. 50 out of 90 subjects, 56%). In the 49 subjects in whom both Methods A and B were feasible, intra-observer reproducibility of LV rotation parameters was better with Method A (variabilities 2 +/- 3 to 10 +/- 9% vs. 2 +/- 4 to 21 +/- 18%). With this method, inter-observer variability varied from 4 +/- 4 to 13 +/- 9% and temporal variability from 4 +/- 6 to 19 +/- 15%. CONCLUSION The most robust method to assess LV rotation with QLAB software is from the mid-myocardium. This method is feasible in approximately two-thirds of subjects and has good intra-observer, inter-observer, and temporal reproducibility, allowing to study changes over time in LV rotation in an individual patient.

Usefulness of real-time three-dimensional echocardiography to identify right ventricular dysfunction in patients with congenital heart disease.

Because right ventricular (RV) dysfunction predicts a poor outcome in patients with congenital heart disease (CHD), regular monitoring of RV function is indicated. To date, cardiac magnetic resonance (CMR) imaging has been the reference method. A more practical, more accessible, and accurate tool would be preferred. We defined normality regarding RV systolic function using healthy controls and tested the ability of real-time 3-dimensional echocardiographic (RT3DE) findings to identify patients with CHD with RV dysfunction. The cutoff values for the RV volumes and ejection fraction (EF) were derived from the CMR imaging findings from 41 healthy controls (mean age 27 +/- 8 years, 56% men). In 100 patients with varying CHDs (mean age 27 +/- 11 years, 65% men), both RT3DE data sets (iE33) and short-axis CMR imaging (1.5 T) were obtained within 2 hours. The RT3DE and CMR RV volumes and EF were calculated using commercially available software. Receiver operating characteristic curves were created to obtain the sensitivity and specificity of the RT3DE data to identify RV dysfunction. Applying the cutoff values derived from the healthy controls using the CMR data of patients with CHD, we identified 23 patients with an enlarged indexed end-diastolic volume, 29 patients with an enlarged indexed end-systolic volume, and 21 patients with an impaired RVEF. The best cutoff values predicting RV dysfunction using the RT3DE findings were identified (indexed end-diastolic volume >105 ml/m(2), indexed end-systolic volume >54 ml/m(2), and EF <43%). The RT3DE findings revealed 23 patients with impaired RVEF, with 95% sensitivity, 89% specificity, and a negative predictive value of 99%. In conclusion, real-time 3-dimensional echocardiography is a very sensitive tool to identify RV dysfunction in patients with CHD and could be applied clinically to rule out RV dysfunction or to indicate additional quantitative analysis of RV function.

Delayed Left Ventricular Untwisting in Hypertrophic Cardiomyopathy

BACKGROUND Almost all patients with hypertrophic cardiomyopathy (HCM) have some degree of left ventricular (LV) diastolic dysfunction. Nevertheless, the pathophysiology remains incompletely characterized. Conceptually, an ideal therapeutic agent should target the underlying mechanisms that cause LV diastolic dysfunction. Assessment of diastolic LV untwisting could potentially be helpful to gain insight into the mechanism of diastolic dysfunction. The purpose of this study was to investigate LV untwisting in patients with HCM and control subjects. METHODS LV untwisting parameters were assessed using speckle-tracking echocardiography in 75 consecutive patients with HCM and compared with those from 75 healthy control subjects. RESULTS Untwisting at 5%, 10%, and 15% of diastole was lower in patients with HCM (all P values < .001) compared with control subjects. Peak diastolic untwisting velocity (-92 +/- 32 degrees/s vs -104 +/- 39 degrees/s, P < .05) and untwisting rate from peak systolic twist to mitral valve opening (MVO) (-37 +/- 20 degrees/s vs -46 +/- 22 degrees/s, P < .01) were lower, while the for diastolic duration normalized time-to-peak diastolic untwisting velocity (17 +/- 9% vs 13 +/- 9%, P < .05) was higher in patients with HCM. Untwisting rate from peak systolic twist to MVO was negatively correlated with the E/A ratio (R(2) = 0.15, P < .01). Peak diastolic untwisting velocity and untwisting rate from peak systolic twist to MVO were increased in mild but decreased in moderate and severe diastolic dysfunction compared with control subjects. CONCLUSION LV untwisting is delayed in HCM, which probably significantly contributes to diastolic dysfunction.

Long-term Outcome and Quality of Life after Arterial Switch Operation: A Prospective Study with a Historical Comparison

AIM.: The study aims to describe the long-term cardiological and psychological results of our first surgical cohort of arterial switch operation (ASO) patients and compare the results with our earlier series of Mustard patients. METHODS.: Twenty-four survivors of ASO operated in our center (1985-1990) were evaluated by electrocardiography, echocardiography, magnetic resonance imaging, exercise testing, 24-hour Holter-monitoring, and health-related quality of life questionnaire. The results were compared with 58 adult Mustard patients who were evaluated in 2001 using the same study protocol. RESULTS.: Arterial switch operation was performed at a median age of 13 days and Mustard operation at 2 years. Median follow-up was 22 years (range 20-25) and 25 years (22-29), respectively. After ASO, survival was better (P =.04). The event-free survival after 22 years was 77% after ASO vs. 44% after Mustard (P =.03). Good systemic ventricular function was present in 93% after ASO vs. 6% after Mustard (P <.01). Exercise capacity in ASO was 85% of predicted, compared with 72% in Mustard patients (P =.01). Aortic regurgitation was found in 21% of ASO patients vs. 16% in Mustard patients. Arterial switch patients vs. Mustard patients reported significantly better quality of life and less somatic complaints. CONCLUSION.: The progression made in surgical treatment for transposition of the great arteries from Mustard to ASO has had a positive impact on survival, cardiac function, exercise capacity, and also self-reported quality of life and somatic complaints. Longer follow-up is warranted to monitor aortic regurgitation.

Multiframe registration of real-time three-dimensional echocardiography time series

Abstract. Mosaicing of real-time three-dimensional echocardiography (RT3-DE) images aims at extending the field-of-view of overlapping images. Currently available methods discard most of the temporal information available in the time series. We investigate the added value of simultaneous registration of multiple temporal frames using common similarity metrics. We combine RT3-DE images of the left and right ventricles by registration and fusion. The standard approach of registering single frames, either end-diastolic (ED) or end-systolic (ES), is compared with simultaneous registration of multiple time frames, to evaluate the effect of using the information from all images in the metric. A transformation estimating the protocol-specific misalignment is used to initialize the registration. It is shown that multiframe registration can be as accurate as alignment of the images based on manual annotations. Multiframe registration using normalized cross-correlation outperforms any of the single-frame methods. As opposed to expectations, extending the multiframe registration beyond simultaneous use of ED and ES frames does not further improve registration results.