Single Nuclei Sequencing Reveals Novel Insights Into the Regulation of Cellular Signatures in Children With Dilated Cardiomyopathy.

BACKGROUND: Dilated cardiomyopathy (DCM) is a leading cause of death in children with heart failure. The outcome of pediatric heart failure treatment is inconsistent, and large cohort studies are lacking. Progress may be achieved through personalized therapy that takes age- and disease-related pathophysiology, pathology, and molecular fingerprints into account. We present single nuclei RNA sequencing from pediatric patients with DCM as the next step in identifying cellular signatures. METHODS: We performed single nuclei RNA sequencing with heart tissues from 6 children with DCM with an age of 0.5, 0.75, 5, 6, 12, and 13 years. Unsupervised clustering of 18 211 nuclei led to the identification of 14 distinct clusters with 6 major cell types. RESULTS: The number of nuclei in fibroblast clusters increased with age in patients with DCM, a finding that was confirmed by histological analysis and was consistent with an age-related increase in cardiac fibrosis quantified by cardiac magnetic resonance imaging. Fibroblasts of patients with DCM >6 years of age showed a profoundly altered gene expression pattern with enrichment of genes encoding fibrillary collagens, modulation of proteoglycans, switch in thrombospondin isoforms, and signatures of fibroblast activation. In addition, a population of cardiomyocytes with a high proregenerative profile was identified in infant patients with DCM but was absent in children >6 years of age. This cluster showed high expression of cell cycle activators such as cyclin D family members, increased glycolytic metabolism and antioxidative genes, and alterations in ß-adrenergic signaling genes. CONCLUSIONS: Novel insights into the cellular transcriptomes of hearts from pediatric patients with DCM provide remarkable age-dependent changes in the expression patterns of fibroblast and cardiomyocyte genes with less fibrotic but enriched proregenerative signatures in infants.

Interrelations of Intraoperative Changes in Cerebral Tissue Oxygen Saturation with Brain Volumes and Neurodevelopment Outcome After the Comprehensive Stage II Procedure in Infants With Hypoplastic Left Heart Syndrome: A Retrospective Cohort Study.

OBJECTIVES: The monitoring of cerebral tissue oxygen saturation by near-infrared spectroscopy (ScerebO2) is used widely in pediatric cardiac anesthesia. However, little information is available on the effects of changes in perioperative ScerebO2 on brain morphology and neurologic outcome. The primary hypothesis tested in this study was that intraoperative ScerebO2 during the comprehensive stage II procedure correlated with brain volumes assessed by magnetic resonance imaging and neurodevelopmental scores. DESIGN: Retrospective observational cohort study. SETTING: University Hospital, Pediatric Heart Centre. PATIENTS AND MEASUREMENTS: In 19 infants, the intraoperative course of ScerebO2 during the comprehensive stage II procedure was examined. Minimal ScerebO2 and integrated ScerebO2 below 45% (AUC) during surgery, as well as cerebral magnetic resonance imaging (MRI) examinations and Bayley III test at the ages of two-to-three years, were analyzed. MAIN RESULTS: A positive correlation between minimal ScerebO2 and intracranial volume (p = 0.0243), total brain volume (p = 0.0243), and white matter volume (p = 0.0276) was observed, as was a negative correlation between AUC and intracranial volume (p = 0.0454) and white matter volume (p = 0.0381), respectively. No association was found between ScerebO2 and Bayley-III Score. CONCLUSION: The correlation between ScerebO2 and brain volumes measured by MRI pointed out a possible importance of neuroprotective strategies aimed at optimizing ScerebO2 during complex congenital heart surgery. That no correlation between ScerebO2 and Bayley III Score was found suggested multifactorial causes for neurologic outcome in children with congenital heart defects.

Hypoplastic Left Heart: Stage-I Will be Performed Interventionally, Soon.

The hypoplasia of left-sided heart structures shows great variability and complexity. What the many variants have in common is that their heart structures are neither fully developed before nor after birth. Fetuses and newborns require an individual therapy depending on anatomy and function of the heart. Fetal interventions focus on improving left heart structures by catheter-based interventions and maternal hyperoxygenation which promotes growth as the left ventricular preload and blood flow within the cavity increase. Stage-I management of newborns with single ventricle physiology is usually based on the Norwood/Sano surgery or the Hybrid approach. Two more steps are required to ultimately achieve a Fontan circulation. Some centers also use the Hybrid approach for subsequent Norwood operation beyond the neonatal period. After the Hybrid approach, a comprehensive stage-II or corrective surgery is performed, the latter if a bi-ventricular circulation is possible. With progressively improved catheter-based interventions, particularly ductal stenting and manipulations of the atrial septum, the next advance is to develop a bespoke flow restrictor that can be easily inserted into the branches of the pulmonary artery. The main goal is to avoid complex heart operations under general anesthesia, followed by substantial intensive care in the neonatal period, especially for patients with complex heart defects. Based on the current state of the art of surgical treatment of hypoplastic left heart syndrome and variants with the Norwood surgery or the Hybrid approach, our main focus is on an alternative percutaneous transcatheter technique in the sense of a completely non-surgical stage-I approach.

Anesthesia for bilateral pulmonary banding as part of hybrid stage I approach palliating neonates with hypoplastic left heart syndrome.

BACKGROUND: Neonatal management of patients with hypoplastic left heart syndrome and complex remains a challenging task, whereby the "hybrid" palliation is often reserved for high-risk patients as a "rescue" procedure. AIM: This study documents the anesthetic challenges and potential complications associated with the Giessen hybrid stage I approach. METHODS: The Giessen hybrid stage I approach is focused on surgical bilateral pulmonary artery banding. Retrospective perioperative data were analyzed. Contrary to a stable group A, inotropic treatment before surgery for treatment of postnatal shock classified patients as unstable (Group B). Clinical outcomes considered were inhospital mortality, duration of postoperative mechanical ventilation, postoperative time at the intensive care unit, perioperative vasoactive medication requirements, and red blood cell transfusion. RESULTS: From June 1998 to December 2015, 185 patients were allocated to Group A (n = 165) and Group B (n = 20). The inhospital mortality was 2.2% with no difference between the groups. There was also no difference in the postoperative time on mechanical ventilation and the time in the intensive care unit. Vasoactive medication was more often required in Group B (100%) compared to Group A (19%). In Group B, more red blood cells were transfused 6.0 ± 8.3 vs 2.0 ± 5.8 mL/kg in Group A (P < .05, 95% CI 0.0 - 2.6). CONCLUSION: Considering a learning curve, anesthesia for surgical bilateral pulmonary artery banding palliating patients with hypoplastic left heart syndrome and complex can safely be performed, independent from the preoperative clinical status.

Transcatheter left atrial decompression in patients with dilated cardiomyopathy: bridging to cardiac transplantation or recovery.

BACKGROUND: Left atrial congestion results from backward failure in dilated cardiomyopathy. We aimed to evaluate feasibility and efficacy of percutaneous atrioseptostomy to create a restrictive atrial septum defect in management of dilated cardiomyopathy.Methods and resultsFrom June 2009 to December 2016, 27 interventions comprised left atria decompressions in 22 dilated cardiomyopathy patients; 9 females; age: 24 days to 36.9 years; weight: 3-50 kg; NYHA-/Ross class IV (n=16). Mean left ventricular ejection fraction was 21.5±9.7% and brain natriuretic peptide was 2291±1992 pg/ml. Dilated cardiomyopathy was classified as chronic (n=9); acute (n=1) myocarditis; idiopathic (n=5); left ventricular non-compaction (n=4); mitochondriopathy, pacemaker induced, and arrhythmogenic (n=3). Atrioseptostomy was concomitantly performed with myocardial biopsies 6.5 days (±11.7) after admission (n=11). Trans-septal puncture was used in 18 patients; foramen ovale dilatation was done in four patients. Mean balloon size was 11 mm (range 7-14 mm); total procedure time was 133±38 minutes. No procedural complications were observed. Mean left atrial pressure decreased from 15.8±6.8 to 12.2±4.8 mmHg (p=0.005), left/right atrial pressure gradient from 9.6±5.6 to 5±3.5 mmHg; brain natriuretic peptide (n=18) decreased from 1968±1606 to 830±1083 pg/ml (p=0.01). One patient unsuitable for heart transplantation died at home despite additionally performed pulmonary artery banding and three further left atrial decompressions; five patients were bridged to transplantation, two died afterwards. Functional recovery occurred in the remaining 14 patients and in six after additional pulmonary artery banding. No patient required assist device. CONCLUSIONS: Percutaneous left atrial decompression is an age-independent, effective palliation treating patients with dilated cardiomyopathy.

Percutaneous pulmonary valve implantation for reconstruction of a patch-repaired right ventricular outflow tract.

Percutaneous pulmonary valve implantation (PPVI) is nowadays an accepted treatment option to repair post-surgical conduit dysfunction of the right ventricular outflow tract (RVOT). In addition, many patients need a pulmonary valve to reconstruct a hemodynamically incompetent native or conduit free outflow tract. Based on our experience with percutaneous stent-valve placement in a cohort of 125 patients, we report here transvenous reconstruction of a conduit-free, patch repaired outflow tract by utilizing balloon-expandable stent-valves in 23 patients with a median age of 22 years (5-60 years). In 20 patients, the step-by-step procedure was performed uneventful with the aimed success. Severe RVOT dysfunction in term of a clinical relevant regurgitation could be changed to mild, as it was confirmed by follow-up color Doppler echocardiography. In a 5-year-old girl a Melody® valve was placed as a surgical-interventional hybrid approach. In one patient, the procedure was complicated by stent embolization during preparation of the RVOT for stent-valve implantation. Reposition of the embolized stent was nevertheless successful for finishing percutaneous valve-implantation. In one patient, surgical approach became necessary because of the inability to advance the balloon-mounted stent-valve through a pre-stented RVOT. Considering the current available balloon-expandable stent-valves, transvenous pulmonary valve implantation is feasible to treat even an incompetent conduit-free RVOT. However, preparation of the RVOT by pre-stenting, in most patients with more than two stents in telescope technique remains challenging. Reconstruction of RVOT by the current available valves is promising only for a carefully selected group of patients.

Two patients with the heterozygous R189H mutation in ACTA2 and Complex congenital heart defects expands the cardiac phenotype of multisystemic smooth muscle dysfunction syndrome.

De novo heterozygous mutations changing R179 to histidine, leucine, or cysteine in the ACTA2 gene are associated with Multisystemic Smooth Muscle Dysfunction Syndrome (MSMDS). Characteristic hallmarks of this condition, caused only by these specific ACTA2 mutations, are congenital mydriasis (mid-dilated, non-reactive pupils), a large persistent ductus arteriosus (PDA), aortic aneurysms evolving during childhood, and cerebrovascular anomalies. We describe two patients, a 3-day-old newborn and a 26-year-old woman, with this unique mutation in association with a huge PDA and an aorto-pulmonary window. In addition, one showed a coarctation of the aortic arch and the other a complete interruption of the aortic arch type A; thereby expanding the spectrum of cardiac congenital heart defect of this syndrome. Each patient displayed a huge PDA and an extra-cardiovascular phenotype consistent with MSMDS. These observations exemplify that a functional alpha 2 smooth muscle actin is necessary for proper cardiovascular organ development, and demonstrate that a very exceptional congenital heart defect (aortopulmonary window) can be caused by a mutation in a gene encoding a contractile protein of vascular smooth muscle cells. © 2017 Wiley Periodicals, Inc.

Creation of a transcatheter fenestration in children with failure of Fontan circulation: Focus on extracardiac conduit connection.

OBJECTIVES: We report our experience with a transcatheter technique to bypass the lung and to thus improve single-ventricle preload and reduce venous congestion in Fontan patients. BACKGROUND: In the absence of a dedicated power source to serve the pulmonary circulation and a significantly elevated transpulmonary pressure gradient, fenestration of the Fontan circulation is an option to improve hemodynamics in patients by relieving excessive systemic venous pressure. METHODS AND RESULTS: From 2005 to 2011, 22 transcatheter fenestrations were performed without any major complications in 19 patients (median age 3.2 years, interquartile range (IQR) 2.7-3.7 years)) with failing Fontan circulation and exceeding systemic venous pressure. In 16 patients, the procedure was performed for acute postoperative failure 1-24 days after surgery. After perforation of the conduit and atrial wall by a Brockenbrough needle and gradual balloon dilation, premounted stents were expanded to create a diabolo configuration with flaring stent edges, leaving a slight but definitive central waist. The procedure resulted in regression of pleural effusions and a significant decrease in systemic venous pressure. Clinical improvement was observed in 16 of the 19 treated patients. Follow-up demonstrated sustained fenestration in 85% of treated patients for at least 24 months. CONCLUSION: Transcatheter creation of a Fontan fenestration is a safe approach despite the anatomic gap between the extracardiac conduit cavity and the atrial wall. Stent implantation allows defining the diameter of the fenestration, reduces spontaneous occlusion, and ensures sustained clinical improvement.

Cardiovascular magnetic resonance assessment of ventricular function and myocardial scarring before and early after repair of anomalous left coronary artery from the pulmonary artery.

BACKGROUND: In patients with anomalous left coronary artery from the pulmonary artery (ALCAPA) left ventricular (LV) dilatation and dysfunction evolves due to diminished myocardial perfusion caused by coronary steal phenomenon. Using late gadolinium enhanced cardiovascular magnetic resonance (LGE-CMR) imaging, myocardial scarring has been shown in ALCAPA patients late after repair, however the incidence of scarring before surgery and its impact on postoperative course after surgical repair remained unknown. METHODS: 8 ALCAPA-patients (mean age 10.0 ± 5.8 months) underwent CMR before and early after (mean 4.9 ± 2.5 months) coronary reimplantation procedures. CMR included functional analysis and LGE for detection of myocardial scars. RESULTS: LV dilatation (mean LVEDVI 171 ± 94 ml/m2) and dysfunction (mean LV-EF 22 ± 10 %) was present in all patients and improved significantly after surgery (mean LVEDV 68 ± 42 ml/m2, p=0.02; mean LV-EF 58 ± 19 %, p<0.001). Preoperative CMR revealed myocardial scarring in 2 of the 8 patients and did not predict postoperative course. At follow-up CMR, one LGE-positive patient showed delayed recovery of LV function while myocardial scarring was still present in both patients. In two patients new-onset transmural scarring was found, although functional recovery after operation was sufficient. One of them showed a stenosis of the left coronary artery and required resurgery. CONCLUSIONS: Despite diminished myocardial perfusion and severely compromised LV function, myocardial scarring was preoperatively only infrequently present. Improvement of myocardial function was independent of new-onset scarring while the impact of preoperative scarring still needs to be defined.

Novel catheter-interventional strategy for intracardiac connecting of total anomalous pulmonary venous return in newborns with hypoplastic left heart-syndrome prior to hybrid approach.

Total anomalous pulmonary venous return (TAPVR) associated with hypoplastic left heart-syndrome (HLHS) is a rare condition, and from the therapeutical point of view associated with a high Aristotle score and thus increased mortality. We report two newborns with HLHS, one with a supracardiac type of TAPVR and mildly obstructed left vertical vein, and the other with a supracardiac type of TAPVR in association with cor triatriatum and severely obstructed left-sided vertical vein. In both patients, radio frequency perforation from the pulmonary venous confluence to the systemic venous atrium was performed with consecutive gradual balloon dilatation, followed by stent placement in one. Hybrid stage I, and comprehensive stage II were successfully performed thereafter. Currently, both are awaiting their Fontan completion. Transcatheter intracardiac connecting of supracardiac type of TAPVR in newborns with HLHS is feasible and might render these children suitable candidates for further hybrid approach.

Beneficial effects of residual right ventricular outflow tract obstruction on right ventricular volume and function in patients after repair of tetralogy of Fallot.

Preservation of the pulmonary valve, even at the expense of a mild residual stenosis, is the current surgical policy for the management of patients with tetralogy of Fallot (TOF). This study aimed to assess the long-term effect of a residual right ventricular outflow tract obstruction (RVOTO) on RV dimension and function. This study prospectively assessed 53 children (mean age, 13.4 ± 6.4 years) after repair of TOF using cardiovascular magnetic resonance imaging. Residual RVOTO on echocardiography was defined as a peak systolic RVOT gradient of 25 mmHg or higher. Patients with RVOTO (n = 29) had significantly less pulmonary regurgitation (25.2 ± 10.6 %) than patients without RVOTO (30.8 ± 9.3 %; p = 0.05) (n = 24). Compared with patients who had no RVOTO, children with RVOTO had significantly smaller RV end-diastolic volume (94.0 ± 2.6 vs 104.0 ± 20.7 ml/m(2); p < 0.05) and end-systolic volume (42.9 ± 20.0 vs 48.9 ± 13.2 ml/m(2); p < 0.05), whereas RV ejection fraction did not differ significantly between the two groups (55.5 ± 8.4 vs 54.0 ± 6.6 %). Restrictive physiology, assessed by late diastolic forward flow in the main pulmonary artery, was equally distributed within the two groups (31 vs 25 %; nonsignificant difference). According to the study data, residual RVOTO after repair of TOF does not affect RV function, whereas RV dimensions and the degree of pulmonary regurgitation are more favorable in the long-term follow-up evaluation of those patients. These results confirm the beneficial effects of the current strategy for repair of TOF.

Two Melodies in concert: transcatheter double-valve replacement.

Percutaneous pulmonary valve implantation has been established as a valuable treatment option for elder children and adolescents with conduit failure in the right ventricular outflow tract. Transcatheter valve implantation in the tricuspid position is restricted to single case reports. A 26-year-old male initially diagnosed with tetralogy of Fallot and hypoplastic pulmonary arteries hitherto underwent a total of five open chest procedures including tricuspid valve replacement with a bioprosthesis and a pulmonary homograft exchange. He now presented with severe right heart failure due to a degenerated pulmonary homograft and calcified, severely stenotic tricuspid bioprosthesis with markedly dilated and reduced right ventricular function. We report on the first successful percutaneous transcatheter double-valve replacement using two Melody valves in the pulmonary and tricuspid position, respectively.

Sox2 transduction enhances cardiovascular repair capacity of blood-derived mesoangioblasts.

RATIONALE: Complementation of pluripotency genes may improve adult stem cell functions. OBJECTIVES: Here we show that clonally expandable, telomerase expressing progenitor cells can be isolated from peripheral blood of children. The surface marker profile of the clonally expanded cells is distinct from hematopoietic or mesenchymal stromal cells, and resembles that of embryonic multipotent mesoangioblasts. Cell numbers and proliferative capacity correlated with donor age. Isolated circulating mesoangioblasts (cMABs) express the pluripotency markers Klf4, c-Myc, as well as low levels of Oct3/4, but lack Sox2. Therefore, we tested whether overexpression of Sox2 enhances pluripotency and facilitates differentiation of cMABs in cardiovascular lineages. METHODS AND RESULTS: Lentiviral transduction of Sox2 (Sox-MABs) enhanced the capacity of cMABs to differentiate into endothelial cells and cardiomyocytes in vitro. Furthermore, the number of smooth muscle actin positive cells was higher in Sox-MABs. In addition, pluripotency of Sox-MABs was shown by demonstrating the generation of endodermal and ectodermal progenies. To test whether Sox-MABs may exhibit improved therapeutic potential, we injected Sox-MABs into nude mice after acute myocardial infarction. Four weeks after cell therapy with Sox-MABs, cardiac function was significantly improved compared to mice treated with control cMABs. Furthermore, cell therapy with Sox-MABs resulted in increased number of differentiated cardiomyocytes, endothelial cells, and smooth muscle cells in vivo. CONCLUSIONS: The complementation of Sox2 in Oct3/4-, Klf4-, and c-Myc-expressing cMABs enhanced the differentiation into all 3 cardiovascular lineages and improved the functional recovery after acute myocardial infarction.

Modified repair of interrupted aortic arch utilizing retroesophageal right subclavian artery based on a neonatal hybrid approach in hypoplastic left heart complex.

OBJECTIVE: Interrupted aortic arch (IAA) combined with an aberrant right subclavian artery (ARSA) is frequently associated with a hypoplastic ascending aorta. Neonatal surgical therapy carries a high risk particularly for aortic arch obstructions during the further follow-up. METHODS: We performed a modified reconstruction of the aortic arch utilizing the ARSA as a natural substitute in a staged surgical approach. In a novel approach, the distal part of the ARSA is reimplanted into the brachiocephalic trunk. RESULTS: In three patients, a novel arch reconstruction was successfully performed during complete biventricular repair. In a follow-up of 60 to 87 months, the reconstructed aortic arch has grown without any signs of obstruction in all three patients. CONCLUSION: Utilizing the ARSA for surgical aortic arch repair is a satisfactory solution, when postnatal borderline left heart obstruction associated with IAA and ARSA is postponed by an initial hybrid approach.

Renal function in children with heart transplantation after switching to CNI-free immunosuppression with everolimus.

Renal impairment because of CNI contributes to long-term morbidity. Therefore, CNI avoiding or sparing treatment strategies are important. In this article, we describe the results of a CNI-free treatment protocol with regard to recovery of renal function. Twenty-eight patients with heart transplantation were switched from CNI regimen to everolimus and mycophenolate, when cGFR was <75 mL/min/1.73 m(2). In all patients, CNI was stopped, when everolimus trough levels of 5-8 ng/L were achieved. Serum creatinine and cGFR were determined before and after 6 and 12 months. Median serum creatinine decreased from 1.2 mg/dL (range 0.7-3.7) before everolimus to 1.0 (range 0.6-1.8) and 1.0 (range 0.5-1.9) mg/dL after 6 and 12 months. Median cGFR was 47.81 (range 18.3-72.6) mL/min/1.73 m(2) before everolimus and 63.1 (range 37.8-108.7) mL/min/1.73 m(2) at six months and 64.8 (range 37.7-106.6) mL/min/1.73 m(2) after 12 months. All changes from baseline to six and 12 months were statistically significant (p < 0.05). Adverse events were infections (n = 3) and rejections (n = 3). Therapy was discontinued in four patients. Conversion to CNI-free immunosuppression resulted in significant improvements of renal function within six months of CNI withdrawal. Side effects are common. However, more studies are required to demonstrate the effectiveness in children.

Heart failure therapy based on interventricular mechanics and cardio-vascular communications.

The heart should not be divided in right and left, whether in health nor in disease. However, the morphological and functional differences between the right and left ventricle should be known and the impact of the ventricle's position considered. Further, the parameters beyond heart rate, contractility, pre- and afterload guaranteeing a sufficient systemic cardiac output have to be integrated in therapeutic measures; preferentially the influence of interventricular mechanics. Despite of recent developments of specific drug therapies, heart failure is associated with a high rate of morbidity and mortality in children. During the progression of heart failure, pulmonary vascular disease is the consequence or the reason for further failing. Clinical symptoms are associated with congestion and low cardiac output at rest or exercise. Improved understanding of the pathophysiological mechanisms particularly of ventricular failure has resulted in the development of innovative therapies that target atrial/ventricular/arterial interactions. Recent advances in interventional and surgical approaches provide promising new strategies to deal with right and left ventricular deterioration. These techniques may delay listing for heart and (heart-) lung transplantation or even make redundant in individual cases. The beneficial effects of these ventricular interaction strategies are mainly based on the mechanics of the interventricular septum and improvement of systolic and diastolic ventricular performance.

Cardiovascular Drug Therapy during Interstage After Hybrid Approach: A Single-Center Experience in 51 Newborns with Hypoplastic Left Heart.

BACKGROUND: Newborns with hypoplastic left heart (HLH) are usually palliated with the Norwood procedure or a hybrid stage I procedure. Hybrid is our preferred approach. Given the critical relationship between stage I, interstage, and comprehensive stage II or advanced biventricular repair, we hypothesized that appropriate drug treatment is a significant therapeutic cornerstone, especially for the management of the high-risk interstage. METHODS: We report a single-center observational study addressing the cardiovascular effects of, in particular, oral ß-blockers and the additional use of angiotensin-converting enzyme (ACE) and mineralocorticoid inhibitors. RESULTS: In total, 51 newborns-30 with HLH syndrome (HLHS) and 21 with HLH complex (HLHC)-with a median bodyweight of 3.0 kg (range 1.9-4.4; nine with bodyweight ≤ 2500 g) underwent an uneventful "Giessen hybrid approach" using a newly approved duct stent. All patients were discharged home with a single, double or triple therapy consisting of ß-blockers, ACE and mineralocorticoid inhibitors; 90% of the patients received bisoprolol, 10% received propranolol, 72% received lisinopril, and 78% received spironolactone. Resting heart rate decreased from 138 bpm (range 112-172; n = 51) at admission to 123 bpm (range 99-139; n = 51) at discharge and 110 bpm before stage II/biventricular repair/heart transplantation (range 90-140; n = 37) accompanied by favorable bodyweight gain. No side effects were evident. CONCLUSION: In view of drug risk/benefit profiles, as well as the variable morphology and hemodynamics, the highly selective ß1-adrenoceptor blocker bisoprolol is our preferred drug for treatment of HLHS/HLHC in the interstage. We avoid using ACE inhibitor monotherapy and exclude potential risks for coronary and cerebral perfusion pressure beforehand.