Pulmonary artery banding in complete atrioventricular septal defect.

OBJECTIVES: To analyze outcomes after pulmonary artery banding (PAB) in complete atrioventricular septal defect (AVSD), with a focus on surgical pathway outcome and timing, survival, and atrioventricular valve function. METHODS: PAB was performed in 50 of 474 infants (11%) from 28 institutions between 2012 and 2018 at a median age of 1.1 months. The median duration of follow-up was 2.1 years. Atrioventricular valve function was assessed by review of pre-PAB and predischarge echocardiograms (median, 9 days postoperatively). Competing-risks methodology was used to analyze the risks for biventricular repair, univentricular repair, and death. RESULTS: At 2 years, the proportions of patients who underwent biventricular repair, univentricular repair, and death were 68%, 13%, and 12%, respectively, with 8% awaiting definitive repair. After PAB, atrioventricular valve regurgitation decreased in 14 infants and increased in 10, but the distribution of regurgitation severity did not change significantly in the total cohort or subgroups. The intended management plan at PAB was deferred biventricular/univentricular decision (23 infants), 2-stage biventricular repair (24 infants), and univentricular repair (3 infants). Among the 24 infants intended for biventricular repair, 23 achieved biventricular repair and 1 died before repair. Survival at 4 years after biventricular repair among patients with previous PAB (93%) was similar to the 4-year survival of the patients who underwent primary biventricular repair (91%; n = 333). CONCLUSIONS: PAB is a successful strategy in complete AVSD to bridge to biventricular repair and has similar post-biventricular repair survival to primary biventricular repair. Changes in atrioventricular valve regurgitation after PAB were variable.

Echocardiographic Assessment of Cardiac Function in Pediatric Survivors of Anthracycline-Treated Childhood Cancer.

BACKGROUND: Anthracycline-induced cardiotoxicity is a major cause of morbidity and mortality in childhood cancer survivors (CCSs). Echocardiographic myocardial strain imaging is recommended in adult patients with cancer, but its role in pediatric CCSs has not been well established. Aims of this study were to determine the prevalence of abnormalities in left ventricular strain in pediatric CCSs, to compare strain with other echocardiographic measurements and blood biomarkers, and to explore risk factors for reduced strain. METHODS: CCSs ≥3 years from their last anthracycline treatment were enrolled in this multicenter study and underwent a standardized functional echocardiogram and biomarker collection. Regression analysis was used to identify factors associated with longitudinal strain (LS). RESULTS: Five hundred forty-six pediatric CCSs were compared with 134 healthy controls. Abnormal left ventricular ejection fraction (<50%) and mean LS (Z score, <-2) was found in 0.8% and 7.7% of the CCSs, respectively. LS was significantly lower in CCSs than in controls, but the absolute difference was small (0.7%). Lower LS in CCSs was associated with older current age and higher body surface area. Sex, cumulative anthracycline dose, radiotherapy, and biomarkers were not independently associated with LS. Circumferential strain, diastolic parameters, and biomarkers were not significantly different in pediatric CCSs. CONCLUSIONS: Global systolic function and LS are only mildly reduced in pediatric CCSs, and most LS values are within normal range. This makes single LS measurements of limited added value in identifying CCSs at risk for cardiac dysfunction. The utility of strain imaging in the long-term follow-up of CCS remains to be demonstrated.

The Congenital Heart Surgeon's Society Complete Atrioventricular Septal Defect Cohort: Baseline, Preintervention Echocardiographic Characteristics.

Quantifying unbalance, the threshold for single ventricle palliation vs biventricular repair in patients with unbalanced complete atrioventricular septal defect (AVSD), is challenging. Using a core laboratory review of baseline echocardiograms, we sought to assess the correlations among commonly used measures of unbalance and common atrioventricular valve (AVV) and ventricular sizes. A single reviewer evaluated baseline echocardiograms from an inception cohort of babies age < 1 year with complete AVSD admitted to 1 of 25 Congenital Heart Surgeon's Society institutions. A standardized echo review protocol of 111 quantitative and qualitative measures was used. Descriptive statistics were computed and Pearson correlation coefficients were calculated to assess correlation among unbalance indices with valvar and ventricular dimensions. Two-hundred fifty-seven baseline echocardiograms of infants with complete AVSD were included. Median age at baseline echocardiogram was 11 days (interquartile range 1-79) and mean atrioventricular valve index was 0.45 ± 0.1. Mean right ventricle/left ventricle inflow angle was 90.2 ± 15.6° and median left ventricular inflow index was 0.46 (interquartile range 0.4-0.5). There are weak or moderate correlations between the measures of unbalance. Correlations between the measures of unbalance with common AVV leaflet or ventricular sizes are also weak to moderate, when statistically significant. Measures of unbalance in common clinical use correlate poorly, or not at all, with one another, common AVV, and ventricular dimensions. The concept of "unbalance" is difficult to define using baseline echocardiographic indices. These findings suggest that the indices may describe different morphologic and functional characteristics. Further analysis is necessary to quantify the contributions of unbalance indices to patient outcome.

Relation of right ventricular mechanics to exercise tolerance in children after tetralogy of Fallot repair.

BACKGROUND: Progressive right ventricular (RV) dysfunction and exercise intolerance are common problems after tetralogy of Fallot (TOF) repair. We investigated RV myocardial deformation and dyssynchrony in children after TOF repair and their association with exercise capacity. METHODS: Asymptomatic children after TOF repair were investigated by 2-dimensional speckle tracking echocardiography, magnetic resonance, and metabolic exercise study. Patients with RV outflow obstruction were excluded. Peak RV longitudinal strain and strain rate (SR) and dyssynchrony (RV intraventricular delay) were compared with healthy controls. Associations between RV strain, dyssynchrony, and exercise capacity were analyzed. RESULTS: Thirty-nine (81%) of 48 TOF patients and 40 healthy controls had adequate RV strain imaging. The TOF patients had moderately dilated RVs and normal RV ejection fraction. Right ventricular peak systolic strain (-23.2% ± 5.1% vs -28.5% ± 8.5%, P < .001) and SR (-1.46 ± 0.68 vs -2.1 ± 0.8, P < .001) were reduced in TOF patients compared with controls. Right ventricular intraventricular delay was higher in TOF patients (146.0 ± 159 vs 71.0 ± 92 milliseconds, P = .008). Decreased RV strain and SR were associated with increased RV dyssynchrony (strain parameter estimate [PE] 6.31 [2.30], P = .007; SR [PE] 11.32 [3.84], P = .004). Increased RV-left ventricular delay was associated with prolonged QRS duration (PE 0.13 [0.058], P = .03) and reduced RV ejection fraction (PE -2.95 [1.275], P = .02). Reduced RV peak SR was associated with decreased exercise peak oxygen uptake (PE 0.14 [0.07], P = .04). CONCLUSIONS: After repair of TOF, asymptomatic children have reduced RV deformation in association with RV dyssynchrony and reduced exercise tolerance.

Impaired right and left ventricular diastolic myocardial mechanics and filling in asymptomatic children and adolescents after repair of tetralogy of Fallot.

AIMS: After tetralogy of Fallot (TOF) repair patients have right ventricular (RV) dysfunction and reduced exercise tolerance. Diastolic dysfunction may be important but is as yet poorly characterized. The early diastolic strain rate (SR) is a measure of ventricular relaxation, and may be useful to assess diastolic mechanics in TOF. We hypothesized that children after TOF repair have diastolic dysfunction and dyssynchrony by this measure, and sought to determine their relationship with pulmonary regurgitation (PR), RV enlargement, and aerobic exercise capacity. METHODS AND RESULTS: We prospectively recruited asymptomatic children after TOF repair. RV and PR volumes were measured by magnetic resonance imaging; Doppler and tissue Doppler indices by echocardiography and RV and left ventricular (LV) early diastolic SR by two-dimensional speckle tracking. Exercise peak oxygen consumption (VO(2)) was determined using bicycle ergometry. Results were compared with healthy controls. We studied 53 TOF patients and 49 age-matched controls. TOF patients had significant PR (2.05 ± 1 L/m(2)) with moderate RV dilatation (157 ± 39 mL/m(2)), low-normal RV ejection fraction (49 ± 8.8%), and moderate QRS prolongation (141 ± 23 ms). The RV outflow gradient was 21.7 ± 16.0 mmHg. Patients had RV diastolic dysfunction vs. controls [reduced tricuspid valve (TV) E/A ratio, E' velocity, and longitudinal diastolic SR; increased right atrial volume and TV E/E' ratio]. LV early diastolic radial and circumferential SR were lower in TOF patients in association with more PR [parameter estimate (PE) 0.177 standard error (SE) (0.08) mL/m(2), P = 0.02] and higher RV volumes [(PE) 0.005 (0.002)mL/m(2), P = 0.01]. Diastolic dyssynchrony was not different in TOF patients vs. controls. CONCLUSION: TOF patients have RV and LV diastolic dysfunction associated with RV enlargement and reduced early filling. SR imaging may be useful to quantify early myocardial diastolic dysfunction in these children.

Echocardiographic assessment of right ventricular volumes: a comparison of different techniques in children after surgical repair of tetralogy of Fallot.

AIMS: Different echocardiographic techniques are available for assessing right ventricular (RV) volumes but their clinical validity has not been well established. We compared the feasibility, reproducibility and accuracy of three different echocardiographic techniques for measuring RV volumes and ejection fraction (EF) in children after tetralogy of Fallot (TOF) repair. METHODS AND RESULTS: Seventy patients (age 14.2 ± 7.3 years) were studied using three-dimensional (3D) volume acquisition analysis (Tomtec, Germany), 2D echo with knowledge-based 3D reconstruction (3DR) (Ventripoint, USA) and the four-chamber area (4C area) methods. Parameters analysed were RV end-diastolic volume (EDV), end-systolic volume and EF. Magnetic resonance imaging (MRI) data were available in 41 patients. Intra- and inter-observer as well as inter-technique variability was assessed using Pearson's correlation analysis (R), coefficient of variance, and Bland-Altman analysis. Feasibility was good for all echo techniques (91% for the 3D, 98% for the 3DR, and 100% for the 4C area method). Intra- and inter-observer variability was low for both 3DR and the 3D echo, while more variability was observed for the 4C method. Compared with MRI volumes, 3DR and 3D underestimated EDV by 6.6 ± 10 and 18.2 ± 17.8 mL, respectively, (P < 0.001), while the 4C area method overestimated the EDV by 9.6 ± 33 mL, not significant due to a wide range. CONCLUSION: Current echocardiographic techniques to assess RV volumes are highly feasible and reproducible in paediatric post-operative TOF patients. When compared with MRI measurements, 3DR was the most accurate technique but requires extra equipment that is not readily available.

Echocardiographic assessment of right ventricular volumes after surgical repair of tetralogy of Fallot: clinical validation of a new echocardiographic method.

BACKGROUND: Assessment of right ventricular (RV) volumes and function is important in patients after tetralogy of Fallot (TOF) repair. Currently, cardiac magnetic resonance imaging (MRI) is considered the clinical reference method for RV volume and function measurements. Three-dimensional (3D) knowledge-based reconstruction derived from two-dimensional echocardiographic imaging with magnetic tracking is a novel approach to RV volumetrics. The aim of this study was to assess the feasibility and reliability of this novel echocardiographic technique in patients after TOF repair. The accuracy of the method was assessed by comparison with measurements obtained by cardiac MRI. METHODS: Thirty patients (mean age, 13.7 ± 2.8 years) after TOF repair, referred for cardiac MRI, were included. Immediately after MRI, echocardiographic image acquisition was performed using a standard ultrasound scanner linked to a Ventripoint Medical Systems unit. Echocardiographic and MRI measurements were performed offline. Parameters analyzed were end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction. Intraobserver, interobserver, and intertechnique variability was assessed using Pearson's correlation analysis, coefficients of variation, and Bland-Altman analysis. RESULTS: Echocardiographic two-dimensionally based 3D reconstruction was highly feasible, with low intraobserver and interobserver variability for EDV and slightly higher variability for ESV and ejection fraction. The 3D reconstruction values for EDV, ESV, and ejection fraction were correlated highly with MRI values, with low coefficients of variation. The agreement between both methods was high. Three-dimensional reconstruction slightly underestimated RV volumes, by 2.5% for EDV and 4.6% for ESV compared with MRI volumes. CONCLUSIONS: In patients after TOF repair, echocardiographic 3D reconstruction is highly feasible, with good reproducibility for measurements of RV EDV. There is good agreement with MRI measurements, with a small underestimation of RV volumes. The use of this method in clinical practice warrants further investigation.

Isovolumic acceleration at rest and during exercise in children normal values for the left ventricle and first noninvasive demonstration of exercise-induced force-frequency relationships.

OBJECTIVES: This study aimed to determine the normal variation of left ventricular (LV) isovolumic acceleration (IVA) in healthy children and to assess the feasibility of an entirely noninvasive method for demonstration of the LV force-frequency relationship (FFR). BACKGROUND: Pediatric cardiologists continue to seek noninvasive, load-independent indexes for the assessment of LV contractility and myocardial reserve. METHODS: Resting LV IVA was measured by echocardiogram in 236 healthy children and compared with their clinical characteristics. Further measurements were made in 51 children at incremental heart rates during semi-recumbent exercise. For these, FFRs were constructed by plotting LV IVA against heart rate. To assess potential clinical applications, pilot FFR data were collected from 16 children previously treated with anthracyclines. RESULTS: In healthy children, median resting LV IVA was 1.2 m/s(2), interquartile range 0.9 to 1.6 m/s(2). Resting LV IVA was unaffected by age, sex, weight, height, and body surface area but associated with baseline heart rate (r = 0.18, p = 0.0006). Noninvasive evaluation of the LV FFR was possible in 98% of subjects. Positive FFRs were confirmed in all the healthy children. By comparison, several of the children with anthracycline exposure demonstrated flattened force-frequency curves that were largely independent of resting LV ejection fraction and suggest reduced contractile reserve. CONCLUSIONS: In children over 7 years, it is possible to demonstrate the LV FFR by interval measurement of IVA during exercise. The availability of pediatric normal values for both this relation and resting LV IVA might facilitate future investigation of LV contractility and myocardial contractile reserve during childhood.

Evaluation of mechanical dyssynchrony in children with idiopathic dilated cardiomyopathy and associated clinical outcomes.

We studied mechanical dyssynchrony and its association with clinical status in children with idiopathic dilated cardiomyopathy (IDC). The SD of QRS to peak systolic velocity interval by tissue Doppler was measured in 12 left ventricular segments, as a dyssynchrony index (DI), in each child with IDC during a 12-month period. Results were compared with a control cohort. We used the adult-defined DI cutpoint of 32.6 ms to define patients with IDC as "dyssynchronous" or "synchronous" and compared clinical status and outcomes (transplantation listing/death) between these groups. Patients with IDC (n = 23) and controls (n = 14) had similar age, gender, and QRS duration. Patients with IDC had a higher DI than controls (44.8 +/- 23.7 vs 19.9 +/- 8 ms, p <0.0001). A DI >32.6 ms defined mechanical dyssynchrony in 65% of patients with IDC. Dyssynchronous and synchronous patients had similar QRS durations. Age at diagnosis, at dyssynchrony evaluation, and duration of clinical illness were similar in the 2 groups. New York Heart Association score was better in dyssynchronous than in synchronous patients (2 vs 3.1, p <0.05). Number of synchronous and dyssynchronous patients reaching the end point of death or transplantation was similar, although synchronous patients had poorer actuarial survival from the time of diagnosis (hazard ratio 3.25, p = .04). In conclusion, left ventricular mechanical dyssynchrony is prevalent in pediatric IDC. QRS duration alone is inadequate to define dyssynchrony in pediatric IDC, whereas the adult-derived DI of >32.6 ms seems applicable to the pediatric population. In this cohort, the presence of mechanical dyssynchrony was not associated with more severe clinical status or adverse outcomes.