Pediatric vascular ring outcomes for surgically repaired vs. unoperated children: a single-center experience.

Background: Vascular rings represent 1% of congenital cardiovascular abnormalities. Phenotypic expression varies from asymptomatic to severe forms related to either oesophageal or tracheal compression. While refinement in prenatal screening led to an increase in fetal diagnosis, optimal management in asymptomatic neonates and infants is currently a matter of debate. We report our center experience of vascular ring management over three decades. Methods: In this single-center retrospective study, data were extracted from patient medical records. To obtain information on symptoms/medication at follow-up, clinical records from pediatric clinics were reviewed. For patients followed in other institutions, a web-based questionnaire was sent to referring pediatricians. Results: Out of 82 patients, 69 were symptomatic (84%). Common symptoms included recurrent respiratory tract infections (43%), stridor (32%), gastro-esophageal reflux (33%), and dysphagia (26%). Diagnosis relied on cardiac ultrasound, barium swallow studies, and chest computerized tomography scan. Surgical repair (thoracotomy 91%) was performed in 79 patients (96%). Median age at repair was 13 [interquartile range (IQR), 4.4-48] months. There was no mortality. Minor complications occurred in 14 patients (18%). Median hospital length of stay was 7 (IQR, 6-9) days. In total, 24% of patients remained symptomatic (median follow-up 54 months). Half of those were asthma-related, with nearly 90% freedom from ring-related symptoms. Conclusions: Most patients were symptomatic at the time of diagnosis. Vascular rings such as pulmonary slings or tracheal compression syndromes require prompt management. Despite surgery, 24% of patients were not symptom-free at follow-up. Finally, surgery in asymptomatic patients resulted in low morbidity supporting the current recommendation of early surgical repair. Level of Evidence: III.

Assessment of left ventricular dyssynchrony by speckle tracking echocardiography in children with duchenne muscular dystrophy.

Prognosis of Duchenne muscular dystrophy (DMD) is related to cardiac dysfunction. Two dimensional-speckle tracking echocardiography (2D-STE) has recently emerged as a non-invasive functional biomarker for early detection of DMD-related cardiomyopathy. This study aimed to determine, in DMD children, the existence of left ventricle (LV) dyssynchrony using 2D-STE analysis. This prospective controlled study enrolled 25 boys with DMD (mean age 11.0 ± 3.5 years) with normal LV ejection fraction and 50 age-matched controls. Three measures were performed to assess LV mechanical dyssynchrony: the opposing-wall delays (longitudinal and radial analyses), the modified Yu index, and the time-to-peak delays of each segment. Feasibility and reproducibility of 2D-STE dyssynchrony were evaluated. All three mechanical dyssynchrony criteria were significantly higher in the DMD group than in healthy subjects: (1) opposing-wall delays in basal inferoseptal to basal anterolateral segments (61.4 ± 45.3 ms vs. 18.3 ± 50.4 ms, P < 0.001, respectively) and in mid inferoseptal to mid anterolateral segments (58.6 ± 35.3 ms vs. 42.4 ± 36.4 ms, P < 0.05, respectively), (2) modified Yu index (33.3 ± 10.1 ms vs. 28.5 ± 8.1 ms, P < 0.05, respectively), and (3) most of time-to-peak values, especially in basal and mid anterolateral segments. Feasibility was excellent and reliability was moderate to excellent, with ICC values ranging from 0.49 to 0.97. Detection of LV mechanical dyssynchrony using 2D-STE analysis is an easily and reproducible method in paediatric DMD. The existence of an early LV mechanical dyssynchrony visualized using 2D-STE analysis in children with DMD before the onset of cardiomyopathy represents a perspective for future paediatric drug trials in the DMD-related cardiomyopathy prevention.Clinical Trial Registration Clinicaltrials.gov NCT02418338. Post-hoc study, registered on April 16, 2015.

Antenatal diagnosis of CHARGE syndrome: Prenatal ultrasound findings and crucial role of fetal dysmorphic signs. About a series of 10 cases and review of literature.

Although the prognosis of CHARGE syndrome can be highly variable from mild until severe, final diagnosis is difficult to establish in utero. The aim of our study is to compare antenatal and postnatal findings in a retrospective cohort of 10 successive patients with a positive CHD7 gene variant in order to identify the specific prenatal features for CHARGE syndrome diagnosis. Fetal ultrasound, follow-up and supplementary investigations are collected and compared to postnatal findings. Congenital heart defect (7/10), choanal atresia (7/10) and tracheoesophageal atresia (4/10) are the most frequent fetal anomalies found. Inner and external ear anomalies appear as the keystone (constant features) for prenatal diagnosis of CHARGE syndrome in fetuses with multiple anomalies and normal microarray karyotype. External ear malformations are identified in all cases by 3D ultrasound when carefully evaluated. MRI and temporal bone CT-Scan are second line useful tools to assess the diagnosis when looking for semicircular canal agenesis, arhinencephaly and/or choanal atresia. Before availability of prenatal exome sequencing in clinical routine, present findings lead to the recommendation that fetuses, with congenital heart defect (mainly septal and conotruncal), cleft lip/palate or unexplained polyhydramnios should carefully be screened for clues suggesting CHARGE syndrome using 2D and 3D ultrasound, MRI and temporal bone CT-Scan. When CHARGE syndrome is suspected with normal molecular karyotype, CHD7 gene sequencing must be offered.

Quality of life assessment in children before and after a successful ablation for supraventricular tachycardia.

BACKGROUND AND OBJECTIVES: Young patients suffering from rhythm disorders have a negative impact in their quality of life. In recent years, ablation has become the first-line therapy for supraventricular arrhythmias in children. In the light of the current expertise and advancement in the field, we decided to evaluate the quality of life in young patients with supraventricular arrhythmias before and after a percutaneous ablation procedure. METHODS: The prospective cohort consisted of patients <18 years with structurally normal hearts and non-pre-excited supraventricular arrhythmias, who had an ablation in our centre from 2013 to 2018. The cohort was evaluated with the PedsQL™ 4.0 Generic Core Scales self-questionnaire prior to and post-ablation. RESULTS: The final cohort included 88 patients consisted of 52 males (59%), with a mean age at ablation of 12.5 ± 3.3 years. Forty-two patients (48%) had a retrograde-only accessory pathway mediating the tachycardia, 38 (43%) had atrio-ventricular nodal re-entrant tachycardia, 7 (8%) had ectopic atrial tachycardia, and 1 (1%) had atrial flutter. The main reason for an ablation was the patient's choice in 53%. There were no severe complications. Comparison between the baseline and post-ablation assessments showed that patients reported significant improvement in the scores for physical health, emotional and social functioning, as well as in the total scores. CONCLUSIONS: The present study demonstrates that the successful treatment of supraventricular arrhythmias by means of an ablation results in a significant improvement in the quality of self-reported life scores in young patients.

Speckle-Tracking Echocardiography in Children With Duchenne Muscular Dystrophy: A Prospective Multicenter Controlled Cross-Sectional Study.

BACKGROUND: Prognosis of Duchenne muscular dystrophy (DMD) is related to cardiac dysfunction. Speckle-tracking echocardiographic (STE) imaging is emerging as a noninvasive functional biomarker to consider in the early detection of DMD-related cardiomyopathy. However, STE analysis has not been assessed in a prospectively controlled study, especially in presymptomatic children with DMD, and no study has used STE analysis in all three displacements (longitudinal, radial, and circumferential) and for both ventricles. METHODS: This prospective controlled study enrolled 108 boys, 36 of whom had DMD (mean age, 11 ± 3.8 years) and 72 of whom were age-matched control subjects in a 1:2 case-control design. Conventional echocardiographic variables were collected for the left and right ventricles. STE analyses were performed in the longitudinal, radial, and circumferential displacements for the left ventricle and in the free wall longitudinal displacement for the right ventricle. The effect of age on the evolution of two-dimensional strain in children with DMD was studied by adding an interaction term, DMD × age, in the models. RESULTS: Conventional echocardiographic measures were normal in both groups. Left ventricular (LV) ejection fraction ranged from 45% to 76% (mean, 63 ± 6%) in the DMD group and from 55% to 76% (mean, 64 ± 5%) in the control group. Global LV strain mean measures were significantly worse in the DMD group for the longitudinal (-16.8 ± 3.9% vs -20.6 ± 2.6%, P < .0001), radial (22.7 ± 11.3% vs 31.7 ± 14%, P = .002), and circumferential (-16.5 ± 3.8% vs -20.3 ± 3.1%, P < .0001) displacements. The decrease of global LV longitudinal strain with age in children with DMD was 0.34% per year more marked than that in control subjects. The LV inferolateral and anterolateral segments were specifically impaired, especially in the basal area. Right ventricular function evaluated using conventional echocardiography and STE analysis was normal and not different between children with DMD and control subjects. CONCLUSIONS: The existence of altered LV strain despite normal LV function in children with DMD represents an important perspective for future pediatric drug trials in DMD-related cardiomyopathy prevention.

Liver and systemic hemodynamics in children with cirrhosis: Impact on the surgical management in pediatric living donor liver transplantation.

Cirrhosis in adults is associated with modifications of systemic and liver hemodynamics, whereas little is known about the pediatric population. The aim of this work was to investigate whether alterations of hepatic and systemic hemodynamics were correlated with cirrhosis severity in children. The impact of hemodynamic findings on surgical management in pediatric living donor liver transplantation (LT) was evaluated. Liver and systemic hemodynamics were studied prospectively in 52 children (median age, 1 year; 33 with biliary atresia [BA]). The hemodynamics of native liver were studied preoperatively by Doppler ultrasound and intraoperatively using invasive flowmetry. Portosystemic gradient was invasively measured. Systemic hemodynamics were studied preoperatively by Doppler transthoracic echocardiography and intraoperatively by using transpulmonary thermodilution. Hemodynamic parameters were correlated with Pediatric End-Stage Liver Disease (PELD) score and the histological degree of fibrosis (collagen proportionate area [CPA]). Cirrhosis was associated with a 60% reduction of pretransplant total liver flow (n = 46; median, 36 mL/minute/100 g of liver) compared with noncirrhotic livers (n = 6; median, 86 mL/minute/100 g; P = 0.002). Total blood flow into the native liver was negatively correlated with PELD (P < 0.001) and liver CPA (P = 0.005). Median portosystemic gradient was 14.5 mm Hg in children with cirrhosis and positively correlated with PELD (P < 0.001). Portal vein (PV) hypoplasia was observed mainly in children with BA (P = 0.02). Systemic hemodynamics were not altered in our children with cirrhosis. Twenty-one children met the intraoperative criteria for PV reconstruction using a portoplasty technique during the LT procedure and had a smaller PV diameter at pretransplant Doppler ultrasound (median = 3.4 mm; P < 0.001). Cirrhosis in children appears also as a hemodynamic disease of the liver, correlated with cirrhosis severity. Surgical technique for PV reconstruction during LT was adapted accordingly. Liver Transplantation 23 1440-1450 2017 AASLD.

Prenatal diagnosis of isolated total anomalous systemic venous connection to the left atrium.

We report the prenatal diagnosis and the neonatal follow-up of a patient with isolated total abnormal systemic venous connection to the left atrium. Right-sided and left-sided superior caval veins and the inferior caval vein were all connected to the left atrium. Pulmonary venous return was normal. This was associated with some right ventricular underdevelopment. To our knowledge, this is the first fetal description of this very rare congenital cardiac malformation.

Evidence of a wide spectrum of cardiac involvement due to ACAD9 mutations: Report on nine patients.

Acyl-CoA dehydrogenase 9 (ACAD9) is a mitochondrial protein involved in oxidative phosphorylation complex I biogenesis. This protein also exhibits acyl-CoA dehydrogenase (ACAD) activity. ACAD9-mutated patients have been reported to suffer from primarily heart, muscle, liver, and nervous system disorders. ACAD9 mutation is suspected in cases of elevated lactic acid levels combined with complex I deficiency, and confirmed by ACAD9 gene analysis. At least 18 ACAD9-mutated patients have previously been reported, usually displaying severe cardiac involvement. We retrospectively studied nine additional patients from three unrelated families with a wide spectrum of cardiac involvement between the families as well as the patients from the same families. All patients exhibited elevated lactate levels. Deleterious ACAD9 mutations were identified in all patients except one for whom it was not possible to recover DNA. To our knowledge, this is one of the first reports on isolated mild ventricular hypertrophy due to ACAD9 mutation in a family with moderate symptoms during adolescence. This report also confirms that dilated cardiomyopathy may occur in conjunction with ACAD9 mutation and that some patients may respond clinically to riboflavin treatment. Of note, several patients suffered from patent ductus arteriosus (PDA), with one exhibiting a complex congenital heart defect. It is yet unknown whether these cardiac manifestations were related to ACAD9 mutation. In conclusion, this disorder should be suspected in the presence of lactic acidosis, complex I deficiency, and any cardiac involvement, even mild.

The diagnostic value of next generation sequencing in familial nonsyndromic congenital heart defects.

To determine the diagnostic value of massive parallel sequencing of a panel of known cardiac genes in familial nonsyndromic congenital heart defects (CHD), targeted sequencing of the coding regions of 57 genes previously implicated in CHD was performed in 36 patients from 13 nonsyndromic CHD families with probable autosomal dominant inheritance. Following variant analysis and Sanger validation, we identified six potential disease causing variants in three genes (MYH6, NOTCH1, and TBX5), which may explain the defects in six families. Several problematic situations were encountered when performing genotype-phenotype correlations in the families to confirm the causality of these variants. In conclusion, by screening known CHD-associated genes in well-selected nonsyndromic CHD families and cautious variant interpretation, potential causative variants were identified in less than half of the families (6 out of 13; 46%). Variant interpretation remains a major challenge reflecting the complex genetic cause of CHD.

Long-Term Results of Balloon Valvuloplasty as Primary Treatment for Congenital Aortic Valve Stenosis: a 20-Year Review.

In the presence of new surgical techniques, the treatment of congenital valvular aortic stenosis is under debate. We reviewed the results and late outcomes of all 93 patients aged 1 day to 18 years, treated with balloon valvuloplasty (BAV) as first-line therapy for congenital aortic valve stenosis in our center from January 1991 to May 2012. Mean age at procedure time was 2.4 years; 37 patients underwent BAV at age ≤30 days (neonates), 29 patients at age ≥1 month and <1 year (infants), and 27 patients were older than 1 year (children). The invasive BAV peak-to-peak aortic valve gradient (mean 59 ± 22 mmHg) was immediately reduced (mean 24 ± 12 mmHg). The observed diminution of gradient was similar for each age group. Four patients had significant post-BAV AI. Mean follow-up after BAV was 11.4 ± 7 years. The last echo peak aortic gradient was 37 ± 18 mmHg and mean gradient was 23 ± 10 mmHg, and two patients had significant AI. Actuarial survival for the whole cohort was 88.2 and 72.9 % for the neonates. All infants, except one, and all children survived. Sixty-six percent of patients were free from surgery, and 58 % were free from any reintervention, with no difference according to age. Freedom from surgery after BAV at 5, 10, and 20 years, respectively, was 82, 72, and 66 %. Our study confirms that BAV as primary treatment for congenital AS is an efficient and low-risk procedure in infants and children. In neonates, the prognosis is more severe and clearly related to "borderline LV."

Twin-to-twin transfusion syndrome: perinatal outcome and recipient heart disease according to treatment strategy.

AIM: The aims of the study were to compare perinatal outcome and assess recipient cardiac disease according to treatment strategy (amnioreduction (AR), laser or selective feticide). METHODS: We retrospectively reviewed 81 consecutive cases of twin-to-twin transfusion syndrome diagnosed before 28 weeks between 1993 and 2007. RESULTS: Although fetuses treated by laser were younger at diagnosis (median 20.4 vs. 22.4 weeks, P = 0.01), they were significantly older at birth (median 33.6 vs. 28.5 weeks, P = 0.004) than those treated by AR. Neonatal morbidity was globally lower after laser than AR, and cardiac insufficiency tended to be less frequent (31% vs. 57%, P = 0.09). There was a trend towards increased perinatal survival after laser treatment (68% vs. 49%, P = 0.1). Heart failure was the cause of death in half (23/46) of the recipients. Fetal heart failure leading to death was 2.7 times more frequent after AR than after laser (n = 11 vs. n = 4), and all four neonatal cardiac deaths occurred after AR. Compared with laser, selective feticide did not further improve the outcome. CONCLUSIONS: Heart failure was an important cause of perinatal morbidity and death. However, laser therapy resulted in a longer diagnosis-delivery interval and lower global neonatal morbidity than AR, with a trend towards increased perinatal survival. Improved outcome after laser treatment compared with AR might be related to its impact on recipient heart disease.

Chemotherapy during pregnancy: effect of anthracyclines on fetal and maternal cardiac function.

Chemotherapy and especially anthracyclines are associated to cardiotoxicity. To assess this potential risk during pregnancy a clinical case-control trial was conducted. Maternal cardiac function, fetal Doppler and fetal cardiac function were evaluated before and after chemotherapy. Maternal cardiac function was assessed by echocardiography before and after the third cycle of anthracyclines and compared with a control group of 10 non-pregnant women matched for age, type of cancer and anthracycline treatment. Ten fetuses exposed to chemotherapy were compared with 10 control fetuses matched for gestational age and gender. Biometry, amniotic fluid index, fetal Doppler and cardiac function were assessed before and after each cycle of chemotherapy. In all, 108 fetal ultrasounds scans were performed before and after 36 cycles of chemotherapy. Anthracycline exposure did not result in acute maternal and fetal cardiac dysfunction in this small cohort study.

Prenatal diagnosis of abnormal cardinal systemic venous return without other heart defects: a case series.

OBJECTIVES: To describe fetal spectrum and echocardiographic characteristics of anomalous systemic venous return (ASVR, cardinal veins) without other structural heart defects (isolated ASVR), evaluate associated extracardiac and genetic anomalies and review neonatal outcome. METHODS: From 2003 to 2009, 369 consecutive fetuses were diagnosed with cardiac malformation, including 27 cases with an isolated ASVR. The following variables were collected: type of ASVR, extracardiac anomalies, karyotype and short-term outcome. RESULTS: The most common forms of ASVR were persistent left superior vena cava (SVC) (n = 15) and interrupted inferior vena cava (IVC) (n = 6). The other ASVR types were a persistent left SVC without a right SVC (n = 4), bilateral agenesis of the SVC with cephalic venous drainage toward the IVC through the azygos system (n = 1) and total ASVR to the coronary sinus (n = 1). Genetic disorders were confirmed in five cases, all with a persistent left SVC, with extracardiac anomalies present in four of them. Ten other patients had extracardiac anomalies detected prenatally or postnatally. When available, ASVR diagnosis was confirmed postnatally in all cases. CONCLUSION: Isolated ASVRs can be accurately diagnosed prenatally and are frequently associated with extracardiac and genetic anomalies. A detailed morphological ultrasound and fetal karyotype should be suggested. Neonatal outcome was mainly related to the associated anomalies.

Considerations for prenatal counselling of patients with cardiac rhabdomyomas based on their cardiac and neurologic outcomes.

Cardiac rhabdomyomas are benign cardiac tumours with few cardiac complications, but with a known association to tuberous sclerosis that affects the neurologic outcome of the patients. We have analysed the long-term cardiac and neurological outcomes of patients with cardiac rhabdomyomas in order to allow comprehensive prenatal counselling, basing our findings on the records of all patients seen prenatally and postnatally with an echocardiographic diagnosis of cardiac rhabdomyoma encountered from August, 1982, to September, 2007. We analysed factors such as the number and the location of the tumours to establish their association with a diagnosis of tuberous sclerosis, predicting the cardiac and neurologic outcomes for the patients.Cardiac complications include arrhythmias, obstruction of the ventricular outflow tracts, and secondary cardiogenic shock. Arrhythmias were encountered most often during the neonatal period, with supraventricular tachycardia being the commonest rhythm disturbance identified. No specific dimension or location of the cardiac rhabdomyomas predicted the disturbances of rhythm.The importance of the diagnosis of tuberous sclerosis is exemplified by the neurodevelopmental complications, with four-fifths of the patients showing epilepsy, and two-thirds having delayed development. The presence of multiple cardiac tumours suggested a higher risk of being affected by tuberous sclerosis. The tumours generally regress after birth, and cardiac-related problems are rare after the perinatal period. Tuberous sclerosis and the associated neurodevelopmental complications dominate the clinical picture, and should form an important aspect of the prenatal counselling of parents.

Huge left ventricular aneurysm in a minimally symptomatic 11-year-old boy.

An 11-year-old boy presented with mild shortness of breath and tachycardia and was diagnosed with a huge left ventricular aneurysm ruptured in a secondary pseudoaneurysm. This report highlights the complementary use of echocardiography and cardiac magnetic resonance imaging in the preoperative assessment of this anomaly.

Right ventricular outflow tract reconstruction with contegra monocuspid transannular patch in tetralogy of Fallot.

BACKGROUND: Pediatric diminutive right ventricular outflow tract (RVOT) reconstruction with homografts or porcine xenografts remains challenging because of limited availability, early degeneration, tissue ingrowth, and child growth. The objective of this study was to assess whether Contegra valved bovine conduit, implanted as monocuspid transannular patch, might be an interesting alternative to overcome these problems. METHODS: We reconstructed the RVOT of 12 patients with tetralogy of Fallot, by the use of a Contegra conduit, tailored as a monocuspid valved transannular patch. The patients were 4 females and 8 males, with a mean age of 12.8 +/- 15.1 months and a mean weight of 7.2 +/- 1.9 kg. The mean pulmonary artery annulus size was 8.2 +/- 1.6 mm. RESULTS: The Contegra tissue was suitable for suturing and for reconstruction of even severely hypoplasic RVOT. We did not observe any sign of conduit or valve degeneration during the follow-up of 28.1 +/- 17.1 months. There were no early or late deaths, and no device-related adverse events. A peak transvalvular gradient of 36.5 +/- 4.7 mm Hg was measured by echocardiography in 4 patients postoperatively, and it decreased during the follow-up to 20 +/- 7.6 mm Hg. Pulmonary valve incompetence was grade 3 in 2 patients and grade 4 in 2 patients. CONCLUSIONS: The Contegra monocuspid transannular patch is widely applicable to RVOT reconstruction with satisfactory midterm results, particularly in patients with small pulmonary annulus. Its main advantage is to reduce the potential risk of supravalvular stenosis due to the narrowing at the distal suture line, as demonstrated when used as conduits, especially in the smaller sizes.

The impact of patch augmentation on left atrioventricular valve dynamics in patients with atrioventricular septal defects: early and midterm follow-up.

OBJECTIVE: Left atrioventricular valve pericardial patch may prevent valve replacement. We assessed patch annular dynamics compared with conventional repair and normal annuli. METHODS: Transesophageal 3-dimensional echocardiography was acquired preoperatively and postoperatively in atrioventricular septal defects (n = 10, 5 patch, 5 conventional repair). Real-time 3-dimensional annular motion at midterm was compared with that of healthy children (n = 10). Parameters were: annular area, perimeter, segmental diameter, bending angle, stenosis, and regurgitation. RESULTS: Regurgitant jet area ratio decreased in both patient groups. Conventional repair reduced annular area (P = .02). Patch repair showed an annular area larger than normal (P = .01). Control subjects had increased systolic area whereas operative groups showed a reduction. Patch repair had segmental diameters similar to normal whereas conventional repair was inhomogeneous. Annular bending angle was maintained after operation. CONCLUSION: Patch repair in pediatrics shows durability without shrinkage or expansion. Improved stenosis and regurgitation does not change by midterm. Operation causes increased annular stiffness and diminished compliance. Neither technique establishes normal annular eccentricity.

Impact of selective laser ablation of placental anastomoses on the cardiovascular pathology of the recipient twin in severe twin-twin transfusion syndrome.

OBJECTIVES: We investigated the impact of selective laser ablation on the cardiovascular pathology of the recipient twin in twin-twin transfusion syndrome. STUDY DESIGN: Fetal echocardiograms and medical records were reviewed from 22 pregnancies with severe twin-twin transfusion syndrome where echocardiography was performed before and after laser. RESULTS: Before laser, cardiomegaly associated with right and/or left ventricular hypertrophy without ventricular dilatation, was observed in most cases. Right ventricular and left ventricular systolic dysfunction (shortening fraction <28%) was present in 59% and 27%, respectively, and diastolic dysfunction (based on inflow and venous Dopplers) in 73%. Shortly after laser, biventricular systolic function improved significantly and diastolic function tended to improve (50%, P = .06). Functional pulmonary atresia, secondary to right ventricular systolic dysfunction, resolved in 2 of 2 cases at post-laser echocardiography. On serial assessment, diastolic function was normal in 7 of 10, hydrops regressed in 4 of 5, and neither progressive myocardial hypertrophy nor anatomical right ventricular outflow obstruction were found. CONCLUSIONS: Selective laser ablation in severe twin-twin transfusion syndrome acutely improves biventricular systolic function and tends to improve diastolic function in the recipient twin.