Assessment of right ventricular volumes in hypoplastic left heart syndrome by real-time three-dimensional echocardiography: comparison with cardiac magnetic resonance imaging.

BACKGROUND: Accurate assessment of right ventricular (RV) volumes and function is important in patients with hypoplastic left heart syndrome (HLHS). We prospectively sought to determine the reproducibility of three-dimensional (3D) echocardiography and its agreement with cardiac magnetic resonance imaging (CMR) in HLHS. METHODS AND RESULTS: Twenty-eight patients underwent CMR followed immediately by transthoracic 3D echocardiography under general anaesthesia. Semi-automated border detection software was used to determine echocardiographic RV volumes. Inter- and intra-observer variability, correlation and levels of agreement between techniques were determined. The median age was 0.37 years (0.18-9.28 years) and weight 6.24 kg (3.42-32.50 kg). Intra- and inter-observer variability was excellent for both techniques. Median (range) measurements for 3D echocardiography and CMR were; end-diastolic volume (EDV) 23.6 mL (6.5-63.2) and 30.6 mL (11.8-87.9), end-systolic volume (ESV) 12.6 mL (3.7-37.0) and 14.9 mL (5.8-33.9), stroke volume (SV) 11.2 mL (2.8-33.0) and 17.1 mL (6.0-54.1), ejection fraction (EF) 48.2% (31.2-64.9), and 56.5% (42.7-72.2). Correlation coefficients were r = 0.85, 0.84, 0.83, and 0.74, respectively (P < 0.01 for all). Volumetric data were expressed as a percentage of the echocardiographic volume to CMR volume. When compared with CMR, 3D echocardiography underestimated EDV, ESV and SV by 26.7% (SD ± 20.2), 10.6% (±28.1), and 37.5% (±20.1), respectively. The difference in volume appeared largest at low ventricular volumes. EF was 8.3% (±7.3) lower by 3D echocardiography compared with CMR. CONCLUSION: Both 3D echocardiography and CMR volumes appear highly reproducible. Measurements obtained by 3D echocardiography are significantly lower than those obtained by CMR, with wide limits of agreement such that these two methods cannot be used interchangeably.

Systolic and diastolic ventricular function assessed by tissue Doppler imaging in children with chronic kidney disease.

Chronic kidney disease (CKD) is associated with elevated cardiovascular risk even during childhood. Tissue Doppler is a sensitive technique for the assessment of ventricular dysfunction with relatively little data available in children with CKD. We report a prospective cross-sectional echocardiographic study at a tertiary center. Forty-nine patients with median (range) age 11.2 years (6.9-17.9), weight 39.6 kg (23.6-99.7) and height 146 cm (122-185). Thirty-one patients were male. Median duration of follow-up for CKD was 7.1 years (range 0.13-16.9). Patients were in CKD stage 3 (n = 37) or 4 (n = 12). Mitral valve E-wave, A-wave, and E/A ratio showed mean (SD) z-scores of 0.08 (0.93), 0.12 (0.82) and -0.13 (0.84), respectively. Tissue Doppler imaging (TDI) at the lateral mitral valve annulus showed e', a', s', and E/e' z-scores mean (SD) -1.10 (0.76), -0.29 (0.92), -1.2 (0.7), and 0.86 (1.1), respectively. There was a significant negative correlation of e' and s' z-score with patient age. E/e' ratio correlated positively with patient age. Blood pressure, left ventricular mass, and relative wall thickness did not correlate with tissue Doppler measurements. The e' and s' velocities correlated significantly with each other, suggesting an interaction of systolic and diastolic dysfunction. Children with CKD may have abnormalities of systolic and diastolic ventricular function on TDI, which are not evident on blood pool Doppler. The tissue Doppler results are consistent with worsening ventricular function in older patients.

Investigating the role of cardiovascular biomarkers in children with pre-dialysis chronic kidney disease: a substitute to echocardiography to detect increased left ventricular mass?

BACKGROUND: Children with chronic kidney disease (CKD) are at increased risk of future cardiovascular (CV) events. Our aim in this prospective single-centre cross-sectional analysis was to assess the relationship of a novel panel of CV biomarkers with left ventricular hypertrophy (LVH). METHODS: A panel of five CV biomarkers (asymmetric dimethyl arginine, high sensitivity C-reactive protein, homocysteine, N-terminal pro-B type natriuretic peptide and uric acid) were measured on the same day as an echocardiogram assessment, in paediatric patients with pre-dialysis stages 3-5 of CKD. RESULTS: Of 73 children aged 5-18 years, LVH, all eccentric, was identified in 38%. Systolic blood pressure (BP), glomerular filtration rate (GFR) and higher intake of calcium-based phosphate binders were significantly worse in children with LVH. In multivariate models analysing each biomarker one at a time with confounders [GFR, systolic BP z-score, anti-hypertensive medication (yes/no) and elemental calcium intake], clinic systolic BP z-score and elemental calcium intake consistently displayed a significant relationship with indexed left ventricular mass (LVMI). None of the evaluated CV biomarkers displayed a significant relationship with LVMI. CONCLUSIONS: In our cohort of children with moderately severe pre-dialysis CKD we have identified no suitable biomarkers to detect LVH. We would therefore recommend that echocardiographic determination of LVMI remains the technique of choice for detection of LVH in children with CKD.

Clinical application of a micro multiplane transoesophageal probe in congenital cardiac disease.

AIM: To assess the quality of imaging modalities of a new micro multiplane transoesophageal echocardiogram probe. METHOD: This is a prospective study of micro transoesophageal echocardiogram S8-3t probe used at a single institution between 15 December, 2009 and 15 March, 2010. The images were compared with standard paediatric or adult probes where possible. Assessors prospectively rated imaging quality - two dimensional, colour flow imaging, pulse wave, and continuous wave Doppler - with a subjective 4-point scale (1 = poor to 4 = excellent). RESULTS: A total of 24 studies were performed on 23 patients, with a median weight = 11.7 kilograms (2.6-72 kilograms) and a median age of 3 years (0.16-60 years). Of the 23 patients, one neonate (2.8 kilograms) had transient bradycardia on probe insertion. Imaging in patients less than 10 kilograms was of full diagnostic value and new information was obtained in eight out of ten patients. Pulse wave and continuous wave Doppler was consistently good across all weight groups. There were high frame rates and good imaging quality to a depth of 4-6 centimetres in all studies. A comparison with a larger alternative probe was available for 12 studies (weight 11.9-72 kilograms). The median micro transoesophageal two-dimensional image quality score was 3 (2-4) and 4 (3-4) with the comparative probe. For the 10- to 30-kilogram group, image quality with the micro transoesophageal echocardiogram probe was judged as inferior to larger standard probes. Adult sized patients had good imaging of near the field, allowing guidance for percutaneous device closure of the atrial septum. CONCLUSION: The micro multiplane transoesophageal echocardiogram probe provides imaging of diagnostic quality in neonates. In larger patients, it offers good imaging of near field structures. In the intermediate-sized child (10-30 kilograms), standard paediatric probes provide better imaging.

Blood pressure control and left ventricular mass in children with chronic kidney disease.

BACKGROUND AND OBJECTIVES: Heart disease is a major cause of death in young adults with chronic kidney disease (CKD). Left ventricular hypertrophy (LVH) is common and is associated with hypertension. The aims of this study were to evaluate whether there is a relationship between LVH and BP in children with CKD and whether current targets for BP control are appropriate. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: In this single-center cross-sectional study, 49 nonhypertensive children, (12.6 ± 3.0 years, mean GFR 26.1 ± 12.9 ml/min per 1.73 m²) underwent echocardiographic evaluation and clinic and 24-hour ambulatory BP monitoring. LVH was defined using age-specific reference intervals for left ventricular mass index (LVMI). Biochemical data and clinic BP for 18 months preceding study entry were also analyzed. RESULTS: The mean LVMI was 37.8 ± 9.1 g/m²·7, with 24 children (49%) exhibiting LVH. Clinic BP values were stable over the 18 months preceding echocardiography. Patients with LVH had consistently higher BP values than those without, although none were overtly hypertensive (> 95th percentile). Multiple linear regression demonstrated a strong relationship between systolic BP and LVMI. Clinic systolic BP showed a stronger relationship than ambulatory measures. Of the confounders evaluated, only elemental calcium intake yielded a consistent, positive relationship with LVMI. CONCLUSIONS: LVMI was associated with systolic BP in the absence of overt hypertension, suggesting that current targets for BP control should be re-evaluated. The association of LVMI with elemental calcium intake questions the appropriateness of calcium-based phosphate binders in this population.

Electrocardiography is a poor screening test to detect left ventricular hypertrophy in children.

BACKGROUND: Detection of left ventricular hypertrophy (LVH) is clinically important because it can be predictive of adverse clinical outcome. However, the best method for detecting LVH in clinical practice is unclear. The aim of this study was to evaluate electrocardiography (ECG) compared with echocardiography (ECHO) as a screening test to detect LVH in a high risk population. METHOD: In a prospective, double-blinded, single centre analysis of a population of children with chronic kidney disease, LVH detected using standard 12-lead ECG (ECG-LVH) was compared with that detected with 2D-guided M-mode ECHO (ECHO-LVH). Two electrocardiographic methods (A and B) were used to diagnose ECG-LVH and compared with three different indexation methods to define ECHO-LVH. RESULTS: 70 consecutively enrolled participants had 107 ECG and ECHO studies performed on the same day. The prevalence of ECHO-LVH ranged from 17% to 55% using different indexation methods. Increased R wave amplitude using recent age and gender specific voltage criteria (ECG method B) demonstrated the highest sensitivity (68-76%) and specificity (43-77%) for detecting ECHO-LVH. The negative predictive value (NPV) for R waves using ECG method B was 52.4% (range 40-68.6%). For all other ECG criteria, sensitivity did not exceed 13% irrespective of the ECG or ECHO method used. CONCLUSIONS: In children, the standard 12-lead electrocardiogram has low sensitivity and low NPV for detecting LVH. These findings are relevant for physiological LVH and should not be extrapolated to detection of hypertrophic cardiomyopathy. In clinical practice, ECHO alone should be used to exclude LVH.

Incidence of left ventricular hypertrophy in children with kidney disease: impact of method of indexation of left ventricular mass.

AIMS: Patients with chronic kidney disease are at high risk of cardiovascular morbidity and mortality. Increased left ventricular mass (LVM) has been shown to be an adverse prognostic factor. LVM may be indexed for body size by different methods related to height, weight, or body surface area (BSA). Our Null hypothesis was that different methods of indexation would not influence categorization as to whether LVM was within normal limits or increased. METHODS AND RESULTS: Prospective study in children with renal disease. M-mode echocardiography assessed by single investigator blinded to medical therapy. Three different partition values and two different published z-scores were used: Method 1: indexation of LVM to the allometric height in metres raised to the power of 2.7 (m(2.7)), value of 38.6 g/m(2.7) denotes 95th percentile. Method 2: indexation of LVM by body weight, ratio of LVM in gm/kg of >3.0 indicating LVH. Method 3: indexation by BSA, 88.9 g/m(2) represents 95th percentile. Z-score based methods from recent studies with z-score >1.65 denoting LVH, Method 4: z-score indexed either for BSA or Method 5, z-score indexed for height(2.7). One hundred and twenty-three echocardiograms were performed in 80 patients with a mean +/- SD age of 13.1 +/- 3.1 years, height 147.2 +/- 15.3 cm, weight 46.4 +/- 15.8 kg, and body mass index 20.8 +/- 4.1 kg/m(2). Method 1, LVH was observed in 68 (55.3%) studies. Method 2, 32 (26%) studies had LVM/kg >3.0. Method 3, 51 studies (41.5%) demonstrated LVH. Method 4, 22 (17.9%) studies demonstrated LVH and Method 5, 25 studies (20%) demonstrated LVH (chi(2) test, P < 0.001). CONCLUSION: Different methods of indexation have a profound influence on the categorization of children with respect to LVH. This will have a major impact on the number of patients who are treated as per current guidelines especially in high-risk groups.