GATA6 mutations: Characterization of two novel patients and a comprehensive overview of the GATA6 genotypic and phenotypic spectrum.

The first human mutations in GATA6 were described in a cohort of patients with persistent truncus arteriosus, and the phenotypic spectrum has expanded since then. This study underscores the broad phenotypic spectrum by presenting two patients with de novo GATA6 mutations, both exhibiting complex cardiac defects, pancreatic, and other abnormalities. Furthermore, we provided a detailed overview of all published human genetic variation in/near GATA6 published to date and the associated phenotypes (n = 78). We conclude that the most common phenotypes associated with a mutation in GATA6 were structural cardiac and pancreatic abnormalities, with a penetrance of 87 and 60%, respectively. Other common malformations were gallbladder agenesis, congenital diaphragmatic hernia, and neurocognitive abnormalities, mostly developmental delay. Fifty-eight percent of the mutations were de novo, and these patients more often had an anomaly of intracardiac connections, an anomaly of the great arteries, and hypothyroidism, compared with those with inherited mutations. Functional studies mostly support loss-of-function as the pathophysiological mechanism. In conclusion, GATA6 mutations give a wide range of phenotypic defects, most frequently malformations of the heart and pancreas. This highlights the importance of detailed clinical evaluation of identified carriers to evaluate their full phenotypic spectrum.

Distribution of strain patterns in children with dilated cardiomyopathy.

OBJECTIVES: This study aimed to evaluate the predicting value of quantitative and qualitative dyssynchrony parameters as assessed by two-dimensional speckle tracking echocardiography (STE) on outcome in children with dilated cardiomyopathy (DCM). Furthermore, the reproducibility of these parameters was investigated. BACKGROUND: In previous studies in adults with heart failure, several dyssynchrony parameters have been shown to be a valuable predictor of clinical outcome. METHODS: This multicenter, prospective study included 75 children with DCM and 75 healthy age-matched controls. Using STE, quantitative (time to global peak strain and parameters describing intraventricular time differences) and qualitative dyssynchrony parameters (pattern analysis) of the apical four-chamber, three-chamber, two-chamber views, and the short axis of the left ventricle were assessed. Cox regression was used to identify risk factors for the primary endpoints of death or heart transplantation. Inter-observer and intra-observer variability were described. RESULTS: During a median of 21 months follow-up, 10 patients (13%) reached an endpoint. Although quantitative dyssynchrony measures were higher in patients as compared to controls, the inter-observer and intra-observer variability were high. Pattern analysis showed mainly reduced strain, instead of dyssynchronous patterns. CONCLUSIONS: In this study, quantitative dyssynchrony parameters were not reproducible, precluding their use in children. Qualitative pattern analysis showed predominantly reduced strain, suggesting that in children with DCM dyssynchrony may be a minor problem.

Six-Minute Walk Test as a Predictor for Outcome in Children with Dilated Cardiomyopathy and Chronic Stable Heart Failure.

Cardiopulmonary exercise testing is an important tool to predict prognosis in children and adults with heart failure. A much less sophisticated exercise test is the 6 min walk test, which has been shown an independent predictor for morbidity and mortality in adults with heart failure. Therefore, we hypothesized that the 6 min walk test could be predictive for outcome in children with dilated cardiomyopathy. We prospectively included 49 children with dilated cardiomyopathy ≥6 years who performed a 6 min walk test. Median age was 11.9 years (interquartile range [IQR] 7.4-15.1), median time after diagnosis was 3.6 years (IQR 0.6-7.4). The 6 min walk distance was transformed to a percentage of predicted, using age- and gender-specific norm values (6MWD%). For all patients, mean 6MWD% was 70 ± 21%. Median follow-up was 33 months (IQR 14-50). Ten patients reached the combined endpoint of death or heart transplantation. Using univariable Cox regression, a higher 6MWD% resulted in a lower risk of death or transplantation (hazard ratio 0.95 per percentage increase, p = 0.006). A receiver operating characteristic curve was generated to define the optimal threshold to identify patients at highest risk for an endpoint. Patients with a 6MWD% < 63% had a 2 year transplant-free survival of 73%, in contrast to a transplant-free survival of 92% in patients with a 6MWD% ≥ 63% (p = 0.003). In children with dilated cardiomyopathy, the 6 min walk test is a simple and feasible tool to identify children with a higher risk of death or heart transplantation.

Parent reports of health-related quality of life and heart failure severity score independently predict outcome in children with dilated cardiomyopathy.

BACKGROUND: Dilated cardiomyopathy in children causes heart failure and has a poor prognosis. Health-related quality of life in this patient group is unknown. Moreover, results may provide detailed information of parents' sense of their child's functioning. We hypothesised that health-related quality of life, as rated by parents, and the paediatric heart failure score, as assessed by physicians, have both predictive value on outcome. Methods and results In this prospective study, health-related quality of life was assessed by parent reports: the Infant Toddler Quality of Life questionnaire (0-4 years) or Child Health Questionnaire-Parent Form 50 (4-18 years) at 3-6-month intervals. We included 90 children (median age 3.8 years, interquartile range (IQR) 0.9-12.3) whose parents completed 515 questionnaires. At the same visit, physicians completed the New York University Pediatric Heart Failure Index. Compared with Dutch normative data, quality of life was severely impaired at diagnosis (0-4 years: 7/10 subscales and 4-18 years: 8/11 subscales) and ⩾1 year after diagnosis (3/10 and 6/11 subscales). Older children were more impaired (p<0.05). After a median follow-up of 3 years (IQR 2-4), 15 patients underwent transplantation. Using multivariable time-dependent Cox regression, "physical functioning" subscale and the Heart Failure Index were independently predictive of the risk of death and heart transplantation (hazard ratio 1.24 per 10% decrease of predicted, 95% confidence interval (CI) 1.06-1.47 and hazard ratio 1.38 per unit, 95% CI 1.19-1.61, respectively). CONCLUSION: Physical impairment rated by parents and heart failure severity assessed by physicians independently predicted the risk of death or heart transplantation in children with dilated cardiomyopathy.

Prospective Evaluation of Sleep Apnea as Manifestation of Heart Failure in Children.

In adults with heart failure, central sleep apnea (CSA), often manifested as Cheyne-Stokes respiration, is common, and has been associated with adverse outcome. Heart failure in children is commonly caused by dilated cardiomyopathy (DCM). It is unknown whether children with heart failure secondary to DCM have CSA, and whether CSA is related to the severity of heart failure. In this prospective observational study, 37 patients (<18 year) with heart failure secondary to DCM were included. They underwent polysomnography, clinical and laboratory evaluation and echocardiographic assessment. After a median follow-up time of 2 years, eight patients underwent heart transplantation. CSA (apnea-hypopnea index [AHI] ≥1) was found in 19 % of the patients. AHI ranged from 1.2 to 4.5/h. The occurrence of CSA was not related to the severity of heart failure. Three older patients showed a breathing pattern mimicking Cheyne-Stokes respiration, two of whom required heart transplantation. CSA was found in 19 % of the children with heart failure secondary to DCM. No relation was found with the severity of heart failure. In a small subset of children with severe DCM, a pattern mimicking Cheyne-Stokes respiration was registered.

Recessive MYL2 mutations cause infantile type I muscle fibre disease and cardiomyopathy.

A cardioskeletal myopathy with onset and death in infancy, morphological features of muscle type I hypotrophy with myofibrillar disorganization and dilated cardiomyopathy was previously reported in three Dutch families. Here we report the genetic cause of this disorder. Multipoint parametric linkage analysis of six Dutch patients identified a homozygous region of 2.1 Mb on chromosome 12, which was shared between all Dutch patients, with a log of odds score of 10.82. Sequence analysis of the entire linkage region resulted in the identification of a homozygous mutation in the last acceptor splice site of the myosin regulatory light chain 2 gene (MYL2) as the genetic cause. MYL2 encodes a myosin regulatory light chain (MLC-2V). The myosin regulatory light chains bind, together with the essential light chains, to the flexible neck region of the myosin heavy chain in the hexameric myosin complex and have a structural and regulatory role in muscle contraction. The MYL2 mutation results in use of a cryptic splice site upstream of the last exon causing a frameshift and replacement of the last 32 codons by 20 different codons. Whole exome sequencing of an Italian patient with similar clinical features showed compound heterozygosity for two other mutations affecting the same exon of MYL2, also resulting in mutant proteins with altered C-terminal tails. As a consequence of these mutations, the second EF-hand domain is disrupted. EF-hands, assumed to function as calcium sensors, can undergo a conformational change upon binding of calcium that is critical for interactions with downstream targets. Immunohistochemical staining of skeletal muscle tissue of the Dutch patients showed a diffuse and weak expression of the mutant protein without clear fibre specificity, while normal protein was absent. Heterozygous missense mutations in MYL2 are known to cause dominant hypertrophic cardiomyopathy; however, none of the parents showed signs of cardiomyopathy. In conclusion, the mutations in the last exon of MYL2 are responsible for a novel autosomal recessive lethal myosinopathy due to defects changing the C-terminal tail of the ventricular form of the myosin regulatory light chain. We propose 'light chain myopathy' as a name for this MYL2-associated myopathy.

Determinants of clinical right ventricular failure after congenital heart surgery in adults.

OBJECTIVES: Right ventricular (RV) failure after cardiac surgery is a clinical entity with high morbidity and mortality. Patients with congenital heart disease (CHD) often undergo right-sided cardiac surgery. The authors aimed to identify determinants of RV failure after cardiac surgery to differentiate patients with increased risk. DESIGN: A retrospective chart review. SETTING: University hospital. PARTICIPANTS: Adults with CHD operated on between January 2001 and January 2011. INTERVENTIONS: Clinical characteristics, laboratory tests, surgical data, and intensive care unit outcome were obtained from medical records. MEASUREMENTS AND MAIN RESULTS: The diagnosis of clinical RV failure was made by careful review of the medical records by 2 independent physicians. Patients only were identified as having RV failure if (1) they had elevated jugular venous pressure, (2) they had impaired postoperative RV function on transthoracic echocardiography, and (3) a diagnosis of RV failure was documented clearly in the medical charts by the treating physician. Data of 412 consecutive patients (median age 36 [range 18-74] years, 56% male) were studied. Eighteen patients had clinical RV failure (4.4%) postoperatively, of whom 6 patients died. Patients undergoing left- and both-sided surgery had an equal risk of developing clinical RV failure as compared with patients undergoing right-sided surgery. In multivariate logistic regression analysis, preoperative impaired RV function, supraventricular tachycardia, and cardiopulmonary bypass time >150 minutes were the strongest determinants of clinical RV failure (p<0.05, for all). CONCLUSIONS: RV failure after cardiac surgery is a serious complication, and occurs regardless of the side of surgery. A tailored approach in patients with CHD at highest risk of RV failure should be considered.

Peri-operative care in adults with congenital heart disease: room for improvement in after care.

BACKGROUND: Patient satisfaction with care has received little attention within the field of congenital heart disease. Our objective was to examine patient satisfaction with the care received when undergoing open-heart surgery in order to identify the best and worst aspects of peri-operative care. Moreover, we examined whether having contact with a specialised nurse in addition to usual care is associated with higher patient satisfaction levels. METHODS: Patient satisfaction was measured by the Satisfaction with Hospital Care Questionnaire, evaluating nine aspects of care by answering individual items and giving overall grades. A top 10 of the best and worst items was selected. Linear regression analyses were used to examine the relationship between having contact with a specialised nurse and patient satisfaction (9 grades), independent of patient characteristics--sex, age, educational level, and health status. RESULTS: Data were available for 75 patients. Grades ranged from 6.74 for "discharge and after care" to 8.18 for "medical care". In all, 21% of patients were dissatisfied with the clarity of the information about lifestyle adjustments given by the surgeon. However, patients who had contact with a specialised nurse were more satisfied with the provided information (B-coefficient is 0.497, p-value is 0.038), independent of patient characteristics. CONCLUSIONS: Patients were satisfied with the received care, although there is room for improvement, especially in discharge and after care and the clarity of the information provided by the surgeon. This gap in care can be compensated for by specialised nurses, as patients who were counselled by a specialised nurse were more satisfied with the provided information.

Extravascular lung water measurement using transpulmonary thermodilution in children.

OBJECTIVE: Measurement of extravascular lung water (EVLW) may be useful in the treatment of critically ill children and can be performed at the bedside using the transpulmonary thermodilution technique (TPTD). There are currently no data to verify the accuracy of these measurements in (small) children. We compared the results of TPTD measurement with the clinical gold standard transpulmonary double indicator dilution (TPDD) measurement in young children. DESIGN: Prospective clinical study in children. SETTING: Catheterization laboratory of a university hospital. PATIENTS AND METHODS: Twelve children (<2 yrs or <12 kg) under general anesthesia. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Measurements were performed using injections of ice-cold indicator (saline or dye) through a central venous catheter. Mean cardiac index was 3.91 L/min/m, mean intrathoracic blood volume index (ITBVITPDD) was 614.9 mL/m, and mean extravascular lung water index (EVLWITPDD) was 11.7 mL/kg. The correlation coefficient between EVLWITPDD and EVLWITPTD is 0.96 (95% confidence interval: 0.87-0.99; p < 0.0001). Bland-Altman analysis for EVLW measurements showed a mean bias of 2.34 mL/kg (18.13%) and limits of agreement +/-2.97 mL/kg (19.78%). The difference between measurements via the right atrium compared with the femoral vein was 2.8% for cardiac output, 8.2% for global end-diastolic volume, and 0.1% for EVLW. CONCLUSION: Clinical measurement of EVLW in young children can be performed using the TPTD with the injection catheter inserted in the femoral vein. Further studies are needed to clarify the clinical value of these measurements.

Myocardial infarction in a neonate with left-sided congenital diaphragmatic hernia.

We present a case study of a newborn girl with a left-sided congenital diaphragmatic hernia and a myocardial infarction (MI). The occurrence of MI in newborns has been associated with cardiac malformations and abnormalities of the coronary arteries or thromboembolization. In our patient, echocardiography revealed left ventricular dysfunction, persistent pulmonary hypertension and an inferolateral MI. Within 24 hours cardiac function and oxygenation did not improve and the baby died. Autopsy showed massive MI, a small aortic valve and ascending aorta, and hypoplasia of the distal aortic arch and isthmus. An accessory spleen was also present. The present report underlines the importance of cardiac evaluation in patients with congenital diaphragmatic hernia.

Genetics, Clinical Features, and Long-Term Outcome of Noncompaction Cardiomyopathy.

BACKGROUND: The clinical outcomes of noncompaction cardiomyopathy (NCCM) range from asymptomatic to heart failure, arrhythmias, and sudden cardiac death. Genetics play an important role in NCCM. OBJECTIVES: This study investigated the correlations among genetics, clinical features, and outcomes in adults and children diagnosed with NCCM. METHODS: A retrospective multicenter study from 4 cardiogenetic centers in the Netherlands classified 327 unrelated NCCM patients into 3 categories: 1) genetic, with a mutation in 32% (81 adults; 23 children) of patients; 2) probably genetic, familial cardiomyopathy without a mutation in 16% (45 adults; 8 children) of patients; or 3) sporadic, no family history, without mutation in 52% (149 adults; 21 children) of patients. Clinical features and major adverse cardiac events (MACE) during follow-up were compared across the children and adults. RESULTS: MYH7, MYBPC3, and TTN mutations were the most common mutations (71%) found in genetic NCCM. The risk of having reduced left ventricular (LV) systolic dysfunction was higher for genetic patients compared with the probably genetic and sporadic cases (p = 0.024), with the highest risk in patients with multiple mutations and TTN mutations. Mutations were more frequent in children (p = 0.04) and were associated with MACE (p = 0.025). Adults were more likely to have sporadic NCCM. High risk for cardiac events in children and adults was related to LV systolic dysfunction in mutation carriers, but not in sporadic cases. Patients with MYH7 mutations had low risk for MACE (p = 0.03). CONCLUSIONS: NCCM is a heterogeneous condition, and genetic stratification has a role in clinical care. Distinguishing genetic from nongenetic NCCM complements prediction of outcome and may lead to management and follow-up tailored to genetic status.

Usefulness of Serial N-terminal Pro-B-type Natriuretic Peptide Measurements to Predict Cardiac Death in Acute and Chronic Dilated Cardiomyopathy in Children.

N-terminal pro-B-type natriuretic peptide (NT-proBNP) is an important predictor of outcome in adults with heart failure. In children with heart failure secondary to dilated cardiomyopathy (DC) markers that reliably predict disease progression and outcome during follow-up are scarce. We investigated whether serial NT-proBNP measurements were predictive for outcome in children with DC. All available NT-proBNP measurements in children with DC were analyzed. Linear mixed-effect models and Cox regression were used to analyze the predictive value of NT-proBNP on the end point of cardiac death (death, heart transplantation, or mechanical circulatory support). During 7 years, 115 patients were included. At diagnosis, median NT-proBNP was high and not predictive for outcome. At any time during follow-up, a twofold higher NT-proBNP resulted in a 2.9 times higher risk in the first year (p <0.001) and a 1.8 times higher risk thereafter (p <0.001). Furthermore, at any time, the slope of log10(NT-proBNP) was significantly predictive for the risk of an end point (0 to 30 days hazard ratio [HR] 3.5, >30 days HR 2.9; >1 year HR 6.4). In patients with idiopathic DC (IDC) at 30 days after diagnosis, NT-proBNP ≥7,990 pg/ml showed a 1- and 2-year event-free survival of 79% and 71% and >1 year after diagnosis NT-proBNP ≥924 pg/ml showed a 2- and 5-year event-free survival of 50% and 40%, whereas below both thresholds event-free survival was 100%. In non-IDC, these thresholds were not predictive for outcome. In conclusion, NT-proBNP at any time during follow-up and its change over time were significantly predictive for the risk of cardiac death in children with DC. In children with IDC >1 year after diagnosis, NT-proBNP >924 pg/ml identified a subgroup with a poor outcome.

Management of children with dilated cardiomyopathy in The Netherlands: Implications of a low early transplantation rate.

BACKGROUND: The policy for listing and transplant for children with dilated cardiomyopathy (DCM) in The Netherlands has been conservative because of low donor availability. The effects of this policy on outcome are reported. METHODS: This was a multicenter, nationwide study performed in 148 children with DCM. The primary outcome was death or heart transplant. RESULTS: Overall, 43 patients (29%) died or were transplanted. Within 1 year of diagnosis, 21 patients died, and only 4 underwent transplantation (3 on mechanical circulatory support). The 1-year survival was 85% (95% confidence interval [CI] = 79-91), and 5-year survival was 84% (95% CI = 78-90). Transplantation-free survival at 1 year was 82% (95% CI = 75-88) and at 5 years was 72% (95% CI = 64-80). Within 1 year of diagnosis, with death as the main end-point (21 of 25, 84%), intensive care unit admission (hazard ratio = 2.6, p = 0.05) and mechanical circulatory support (hazard ratio = 3.2, p = 0.03) were risk factors (multivariable Cox analysis); inotropic support was longer in patients reaching an end-point. At >1 year after diagnosis, with transplantation as the main end-point (15 of 18, 83%), age >6 years (hazard ratio = 6.1, p = 0.02) was a risk factor. There were 56 (38%) children who recovered, 50% within 1 year of diagnosis. Recovery was associated with younger age; was similar in patients with myocarditis (43%) and idiopathic disease (41%); and was similar in patients initially admitted to the intensive care unit, admitted to the ward, or treated as outpatients. CONCLUSIONS: The transplantation rate in our cohort in the first year was low, with 1-year and 5-year survival rates similar to other cohorts. Our results suggest that a conservative approach to list children for transplantation early after presentation may be justifiable except for patients with prolonged intensive care unit or mechanical circulatory support.

'The sedentary heart': physical inactivity is associated with cardiac atrophy in adults with an intellectual disability.

BACKGROUND: The cardiac muscle is well regulated in response to changes in loading conditions. This cardiac plasticity has been studied intensively and is well known in trained athletes. Conversely, the mechanisms leading to the opposite response are less clear. The aim of this study was to investigate left ventricular (LV) dimensions in a physically inactive population of adults with an intellectual disability. METHODS: Adults with an intellectual disability with and without Down syndrome (DS) and healthy controls were included (n=182). Echocardiography was performed in all included subjects and physical activity was measured by means of a questionnaire. RESULTS: Physical activity was lower in adults with an intellectual disability compared to controls (p<0.001). In DS, iLVM was significantly lower compared to controls (64 ± 17 g/m(2) vs. 94 ± 17 g/m(2)p<0.001). Non-DS adults with an intellectual disability had higher iLVM (72 ± 16 g/m(2)) compared to subjects with DS, although not significantly different (p<0.08). LV volumes were significantly smaller in adults with DS compared to both controls and non-DS adults with an intellectual disability (p<0.001). Moderate diastolic dysfunction was found in 57% of the adults with an intellectual disability. In 48 children with DS and 79 controls, mean LV end diastolic diameter was not significantly different during childhood. CONCLUSIONS: LV dimensions are significantly smaller in adults with an intellectual disability compared to controls. These findings appear to be lifestyle related as differences become manifest at adulthood and adults with an intellectual disability generally experience a sedentary lifestyle. Presumably, physical inactivity leads to a condition of cardiac atrophy.

Fatal coronary artery disease in an infant with severe mucopolysaccharidosis type I.

A previously healthy 10-month-old boy was referred to our hospital because of coarse facial features that were suggestive of lysosomal storage disease. Apart from noisy respiration, there was no medical history. Elevated levels of urinary glycosaminoglycans and complete deficiency of leukocyte α-l-iduronidase indicated severe mucopolysaccharidosis type I. A chest radiograph revealed a markedly enlarged heart, and echocardiography revealed hypertrophic cardiomyopathy. While hematopoietic stem cell transplantation was being planned, progressive cardiac failure developed with a striking hypokinesia of the left-ventricle free wall. In combination with ischemic changes on the electrocardiogram, this was suggestive of coronary artery disease. Results of coronary echo Doppler interrogation were inconclusive, and intravascular ultrasound in this little infant was not feasible. Despite the patient's small size, a successful selective coronary angiography was performed and revealed diffuse narrowing of the left coronary artery with collateral flow from the right coronary artery. Enzyme-replacement therapy was started immediately in an attempt to improve myocardial performance. Evaluation after 3 months, however, revealed complete obliteration of the left coronary main stem with diffuse hypokinesia/akinesia of the left ventricle. At the age of 13 months the boy died of terminal cardiac failure. This case report illustrates the importance of considering early development of coronary artery disease in children with severe mucopolysaccharidosis type I and cardiomyopathy.

Pericarditis as complication of appendicitis.

Pericarditis as a complication of appendicitis is a rare event. In a 25-year period we encountered two pediatric cases with this severe complication due to (a)typical presentation of appendicitis resulting in small bowel obstruction, intraabdominal abscesses, constrictive pericarditis, and purulent pericarditis.