Cardiac Function and Serum Biomarkers throughout Staged Fontan Palliation: A Prospective Observational Study

Fontan patients undergo multiple cardiothoracic surgeries in childhood. Following these procedures, ventricular function is temporarily decreased, and recovers over months. This is presumably related to cardiopulmonary bypass, but this is incompletely understood. Throughout the Fontan palliation, cardiac function is also affected by volume unloading. We aimed to gain insight into the biological processes related to impaired ventricular function and recovery following Fontan palliations using a panel of biomarkers. Furthermore, we described changes in ventricular function across the Fontan palliation due to volume unloading. We performed a prospective multicenter observational study in patients undergoing partial (PCPC) or total cavo-pulmonary connection (TCPC). Patients underwent assessment-including echocardiography and blood sampling-before surgery (T1), at first follow-up (T2), and 1 year after their procedures (T3). Blood samples were analyzed using a biomarker panel (OLINK CVD-III). Ninety-two biomarkers were expressed as principal components (PC) to limit multiple statistical testing. We included 32 PCPC patients aged 7.2 [5.3-10.3] months, and 28 TCPC patients aged 2.7 [2.2-3.8] years. The single ventricular longitudinal strain (SV GLS) temporarily decreased for PCPC patients at T2 (-15.1 ± 5.6 (T1) to -13.5 ± 5.2 (T2) to -17.3 ± 4.5 (T3), p < 0.047 for all differences), but not following TCPC. The serum biomarkers were expressed as 4 PCs. PC1, including biomarkers of cell-cell adhesion, was not related to any patient characteristic. PC2, including biomarkers of superoxide anion regulation, increased at T2. PC3, including biomarkers of cardiovascular development, related to the stage of Fontan palliation. PC4 was of uncertain biological or clinical significance. No PC was found that related to ventricular performance. The SV GLS was temporarily diminished following PCPC, but not following TCPC. Several biomarkers were related to post-operative stress and adaptation to the PCPC or TCPC circulation, but none were related to the outcome.

Screening, diagnosis and follow-up of Brugada syndrome in children: a Dutch expert consensus statement

Brugada syndrome (BrS) is a rare inherited arrhythmia syndrome. Affected children may experience life-threatening symptoms, mainly during fever. The percentage of SCN5A variant carriers in children is higher than in adults. Current diagnostic and follow-up policies for children with (a family history of) BrS vary between centres. Here, we present a consensus statement based on the current literature and expert opinions to standardise the approach for all children with BrS and those from BrS families in the Netherlands. In summary, BrS is diagnosed in patients with a spontaneous type 1 electrocardiogram (ECG) pattern or with a Shanghai score ≥ 3.5 including ≥ 1 ECG finding. A sodium channel-blocking drug challenge test should only be performed after puberty with a few exceptions. A fever ECG is indicated in children with suspected BrS, in children with a first-degree family member with definite or possible BrS according to the Shanghai criteria with a SCN5A variant and in paediatric SCN5A variant carriers. In-hospital rhythm monitoring during fever is indicated in patients with an existing type 1 ECG pattern and in those who develop such a pattern. Genetic testing should be restricted to SCN5A. Children with BrS and children who carry an SCN5A variant should avoid medication listed at www.brugadadrugs.org and fever should be suppressed. Ventricular arrhythmias or electrical storms should be treated with isoproterenol infusion.

Non-invasive identification of slow conducting anatomical isthmuses in patients with tetralogy of Fallot by 3D late gadolinium enhancement cardiovascular magnetic resonance

Funding Acknowledgements

Type of funding sources: None.

Background

Patients with repaired tetralogy of Fallot (rTOF) remain at risk of sudden cardiac death due to reentrant sustained monomorphic ventricular tachycardia (SMVT). Slow conducting anatomical isthmuses (SCAI), in particular SCAI3 at the outlet septum, bordered by the pulmonary annulus and the ventricular septal defect patch, are the dominant substrate for SMVT. Electroanatomical mapping (EAM) is the invasive gold standard to identify SCAIs, and transection of SCAI by catheter ablation has been correlated with favorable long-term outcome. Non-invasive identification of SCAI for risk stratification and treatment planning is needed but has not been established yet. Three-dimensional (3D) late gadolinium-enhanced (LGE) cardiovascular magnetic resonance (CMR) facilitates accurate visualization of morphologically complex hearts with high-spatial resolution.

Objective

The study thought to determine whether 3D LGE-CMR can identify SCAIs.

Methods

Consecutive patients with rTOF who underwent right ventricular (RV) EAM and 3D LGE-CMR were included. LGE-CMR-derived 3D RV reconstructions were created (ADAS-3D) and merged with 3D RV EAM data. Mapping points were superimposed on the CMR-derived 3D reconstruction allowing for direct comparison of EAM data and local signal intensity (SI). The optimal SI cut-off to identify low bipolar voltage (LBV, BV&lt;1.76mV) was determined by receiver operating characteristic carve. An abnormal AI on LGE-CMR was defined as AI with continuous SI above the obtained cut-off connecting AI borders.

Results

Forty-eight rTOF patients (34±16 years, 58% male) were included. At EAM, 21 patients had normal AI, and 20 and 7 had a SCAI (&lt;0.5m/s) or blocked AI, which was AI3 in all. Patients with SCAI showed low BV of AI3 (median 0.7 [range 0.25-2.59] mV). In 11 patients, 14 SMVTs could be induced, all related to SCAI3.

A total of 9240 points were analyzed, showing a significant correlation between BV and SI (R=0.4, P&lt;0.001). The optimal SI cut-off to identify LBV was 42% of the maximal SI (MSI) (AUC 0.80; sensitivity, 74%; specificity, 78%). Using this cut-off of MSI, a SCAI or blocked AI3 could be correctly identified by LGE-CMR in all 27 patients, and a normal AI3 could be correctly confirmed by LGE-CMR in 14/21 patients with normal EAM findings (Figure). The sensitivity and specificity of 3D LGE-CMR for identifying SCAI or blocked AI3 were 100% and 67%, respectively. Of note, among patients with normal EAM findings, those with abnormal AI3 on LGE-CMR had significantly lower BV of AI3 than those with normal AI3 on LGE-CMR (2.06 [Range, 1.62-2.60] vs. 3.53 [2.22-5.67] mV, P&lt;0.01).

Conclusion

3D LGE-CMR can identify SCAI with 100% sensitivity and may identify diseased AI3 even before critical conduction delay occurs. This technique may allow for non-invasive risk stratification of VT and can refine patient selection for invasive EAM.

The sports cardiology team: personalising athlete care through a comprehensive, multidisciplinary approach

Funding Acknowledgements

Type of funding sources: Other. Main funding source(s): Dutch National Olympic Committee & National Sports Federation (NOC*NSF)Amsterdam Movement Sciences (AMS)

Background/Introduction

Multidisciplinary teams (MDTs) are an integral part of cardiology. In sports cardiology, multidisciplinary expertise is required to differentiate between extraordinary pathophysiological adaption and pathology. In addition, expert consensus-based sports advice should be prescribed with care considering the potential severe impact on (professional) sports careers. A formally organised sports cardiology MDT could potentially improve quality of care; we therefore established a formally organised sports cardiology MDT at the Amsterdam UMC in April 2019, aiming to facilitate the diagnostic process, enhance the process of formulating optimal sports advice, and to maximise safety in sports. However, no studies have reported on the effects of such teams.

Purpose

To systematically investigate and document infrastructure, practices, recommendations, and clinical consequences of a sports cardiology MDT.

Methods

We retrospectively analysed all reviewed athletes of our (online) bimonthly sports cardiology MDT meetings (April 2019 to January 2021). The MDT consisted of a permanent panel of experts in sports cardiology, sports- and exercise medicine, cardio/clinical genetics, paediatric cardiology, cardiovascular imaging, and electrophysiology (Figure 1). Cases were referred (inter)nationally by sports physicians or cardiologists. The primary objective of this study was to investigate the 2 years of experiences of practices, recommendations, and clinical consequences of a formal sports cardiology MDT.

Results

In total 115 athletes underwent MDT review, mean age 32 (SD 16.0) years, 11% women, 65% recreational athletes, and 54% performed 'mixed' type of sports. MDT review led to diagnosis revision of ‘suspected cardiac pathology’ to ‘no cardiac pathology’ in 44/115 (38%) (Figure 2) and increased the number of definitive diagnoses; 77/115 before to 109/115 after MDT review (P&lt;0.05). We observed less ‘total sports restrictions’ (6 to 0 p&lt;0.05) and more tailored sports advice concerning ‘no peak load/specific maximum load’ (10 to 26 p&lt;0.05) (Figure 2). At 14 (± 6) months follow-up, 112 (97%) athletes reported no cardiovascular events, 111 (97%) no (new) cardiac symptoms, 113 (98%) adherence to MDT sports advice, and no diagnoses were revised.

Conclusion

Our experiences with a comprehensive sports cardiology MDT demonstrate that this approach leads to a higher percentage of definitive diagnoses and fewer diagnosis of cardiac pathology, more tailored treatment- and sports advice, high rates of sports advice adherence, and less total sports restrictions. Our findings highlight the added value of dedicated sports cardiology MDTs in care for elite, professional, and recreational athletes and patients who wish to engage in sports and exercise.

Functional echocardiographic and serum biomarker changes following surgical and percutaneous atrial septal defect closure in children

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Dutch Heart Foundation

Background

Ventricular performance is temporarily reduced following surgical atrial septal defect (ASD) closure. Cardiopulmonary bypass and changes in loading conditions are considered important factors, but this phenomenon is incompletely understood. We aim to characterize biventricular performance following surgical and percutaneous ASD closure and to relate biomarkers to ventricular performance following intervention.

Methods

In this multicenter prospective study, children scheduled for surgical or percutaneous ASD closure were included. Subjects were assessed pre-operatively (T1); in the 2nd week post-intervention (T2) and 1 year post-intervention (T3). At each time point an echocardiographic study and a panel of biomarkers was obtained.

Results

Sixty-three patients (age 4.1 [3.1–6.1] years) were included. Forty-three patients underwent surgery. At T2 right ventricular (RV) global longitudinal strain (GLS) was decreased for the surgical, but not the percutaneous, group (-17.6 ± 4.1 versus -27.1 ± 3.4, p&lt;.001). A smaller decrease was noted for left ventricular (LV) GLS at T2 for the surgical group (surgical -18.6 ± 3.2 versus percutaneous -20.2 ± 2.4, p=.040). At T3 LV performance returned to baseline, while RV performance improved, but did not reach pre-intervention levels. Cadherin-5, chitotriosidase-1, integrin-beta-2 and urokinase differed across time points and related to favorable RV GLS at T2.

Conclusions

Right, and to a lesser degree left, ventricular performance was reduced early after surgical ASD closure, possibly related to cardiopulmonary bypass. RV performance at T3 remained below baseline levels, probably related to changed loading conditions. Several biomarkers showed a pattern over time similar to ventricular performance and related to cardiac function at early follow-up. These markers may provide insight into the processes that affect ventricular function.

The sports cardiology team: personalizing athlete care through a comprehensive, multidisciplinary approach

Background/Introduction

Multidisciplinary teams (MDT) are an integral part of cardiology. In sports cardiology wide area of expertise is required to differentiate between extraordinary pathophysiological adaption and pathology. In Addition, expertise-based sports advice should be prescribed with great care considering the great impact on (professional) sports careers. Specific guidelines for the composition of MDT's for sports cardiology are currently lacking. We established a sports cardiology MDT in April 2020 (Amsterdam UMC), consisting of experts in the fields of sports medicine, cardiogenetics and paediatric cardiology, cardiovascular imaging and electrophysiology, with bi-monthly meetings. Cases were contributed from cardiologists or referred nationally for expertise with patients/athletes varying from recreational to elite-level sports.

Purpose

To describe our infrastructure and utilization of a sports cardiology MDT, and to justify the need for a sports cardiology MDT.

Methods

We retrospectively analysed all MDT reviewed cases (from April 2020 to April 2021), and collected follow-up data 1 year after initial MDT review. Data were classified according to type/level of sports. We compared diagnosis and/or reason for referral and sports advice at initial MDT application and after panel review. In addition we abstracted data on occurrence of cardiac symptoms and/or cardiac events, and adherence to sports advice.

Results

112 cases underwent MDT review, with a mean age of 32 (SD 16.0) years. In total 12% were women, 38% professional athletes, and 30% engaged in high dynamic/low static sports. Reasons for referral were personalised sports advice in 48%, expert opinion in 28%, and abnormal ECG/CMR/CPX in 24%. The diagnosis was revised in 55% (n=61), main groups; 1) suspicion of (non-specified) cardiomyopathy (CMP) to no cardiac pathology in 20% (n=12), and 2) “cardiac abnormalities with no clear diagnosis” to “no cardiac pathology” in 36% (n=22) (Figure 1). Sports advice was revised to more personalized sports advice in 30% (n=34) (Figure 2), main groups; no restriction to no peak load/specific maximum load in 38% (n=13), and no restrictions to no competitive sports in 26% (n=9). At 1 year follow-up, the (sports) advice was adhered in 99,98% (n=111), and cases with no sports restrictions reported no cardiac symptoms in 99% (n=72/73), and no major acute cardiovascular events in 100% (73/73). No further revisions of diagnoses were found to have taken place.

Conclusion

Our experience with a comprehensive, sports cardiology MDT demonstrates that such an approach is feasible, and leads to more personalised treatment- and sports advice in athletes. Medium-term adherence to sports advice given is high. A team-based approach also leads to a higher percentage definitive diagnoses. Our findings serve as a proof-of-concept of the added value of the sports cardiology team in care for athletes and patients who wish to engage in sports and exercise.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Dutch Olympic Committee*Dutch Sports Federation (NOC*NSF)Amsterdam Movement Sciences (AMS) Figure 1. Revised diagnosis before and after panel review (N=61)Figure 2. Revised sports advice before and after panel review (N=34)

Improvement of physical activity levels in children and adolescents after surgery for congenital heart disease: preferences and use of physical therapy

PURPOSE

After surgery for congenital heart disease in children and adolescents, an active lifestyle is important to achieve and maintain good physical fitness. This study aimed to describe physical activity, as well as the use of patients' and parents' preferences for rehabilitative care after surgery for congenital heart disease.

METHODS

This cross-sectional study included patients aged 4-16 years old, who had undergone surgery for congenital heart disease 2 years prior to the study onset. Patients and/or parents were invited to complete questionnaires on physical activity, and on their preferences for, and -use of, rehabilitative care after surgery.

RESULTS

Forty-five of the 92 eligible patients and/or parents completed the questionnaires. The median age of the children was 12.2 years (IQR 7.8-16.1). Two children (4%) met the recommendations for taking part in moderate physical activity and 13 (29%) having done so for vigorous physical activity. Postoperatively 15 children (33%) had had physical therapy in primary care. More than 50% of the patients/parents would have preferred to have had more information on physical activity and to have taken part in an individual exercise program delivered during their primary care.

CONCLUSION

The majority of eligible patients do not meet public health recommendations for engaging in physical activity and do not use physical therapy after surgery for congenital heart disease. The majority of patients and parents preferred more information as well as individual physical therapy treatments.Implications for rehabilitationsTwo years after surgery for congenital heart disease children and adolescents are less active compared to typically developing peers.Patients with a congenital heart disease and their parents need more information and support regarding stimulation of physical activity and physical fitness after heart surgery.In the postoperative process, a well-structured and supportive (individual) rehabilitation program should be introduced to improve physical activity and physical fitness.

The brisk-standing-test for long QT syndrome in prepubertal school children: defining normal

Aims

Long QT syndrome (LQTS) is associated with malignant arrhythmias and sudden death from birth to advanced age. Prolongation of the QT-interval, may however be concealed on standard electrocardiograms (ECG). The brisk-standing-test (BST) was developed to guide LQTS-diagnosis and treatment in adults. We hypothesized that the BST may be used in prepubertal children to identify LQTS subjects. Accordingly, reference values for the BST should be available to prevent incorrect diagnosis and treatment of LQTS. In this study, we aim to present reference values for prepubertal children.

Methods and results

Healthy, prepubertal children, aged 7-13 years underwent a standard supine resting ECG and during continuous ECG recording performed a BST. The QT-interval and heart rate corrected QTc were measured during the different BST stages. Fifty-seven children, 29 boys (10.2 ± 1.1 years) and 28 girls (9.9 ± 1.1 years) were included. Baseline characteristics and response to standing were not statistically different for boys and girls: mean supine pre-standing heart rate 74 ± 9 vs. 77 ± 9 bpm, supine pre-standing QTc 406 ± 27 vs. 407 ± 17 ms, maximal heart rate upon standing 109 ± 11 vs. 112 ± 11 bpm, and QTc at maximal heart rate 484 ± 29 vs. 487 ± 35 ms. The QT interval corrected for heart rate-prolongation at maximal tachycardia after standing was 79 ± 26 (19-144) ms, which is significantly longer than previously published values in adults (50± 30 ms).

Conclusions

The QT interval corrected for heart rate prolongation after brisk standing in healthy prepubertal children is more pronounced than in healthy adults. This finding advocates distinct prepubertal cut-off values because using adult values for prepubertal children would yield false positive results with the risk of incorrect LQTS-diagnosis and overtreatment.

Fetuses with Isolated Congenital Heart Defects Show Normal Cerebral and Extracerebral Fluid Volume Growth: A 3D Sonographic Study in the Second and Third Trimester

OBJECTIVE

The aim of our study is to explore whether the cerebral growth is delayed in fetuses with congenital heart defects (CHD) in the second and early third trimester.

METHODS

A prospective cohort study was conducted in 77 CHD cases, with 75 healthy controls. 3D cerebral volume acquisition was performed sequentially. The volumes of the fetal hemicerebrum and extracerebral fluid were compared by linear regression analysis, and the Sylvian fissure was measured.

RESULTS

Between 19 and 32 weeks of gestation, 158 measurements in cases and 183 measurements in controls were performed (mean 2.2/subject). The volume growth of the hemicerebrum (R2 = 0.95 vs. 0.95; p = 0.9) and the extracerebral fluid (R2 = 0.84 vs. 0.82, p = 0.9) were similar. Fetuses with abnormal oxygen delivery to the brain have a slightly smaller brain at 20 weeks of gestation (p = 0.02), but this difference disappeared with advancing gestation. CHD cases demonstrated a slightly shallower Sylvian fissure (mean ratio 0.146 vs. 0.153; p = 0.004).

CONCLUSIONS

Our study shows no differences in cerebral growth, studied in an unselected cohort, with successive cases of isolated CHD. Even in the severest CHD cases, cerebral size is similar in the early third trimester. The cause and meaning of a shallower Sylvian fissure is unclear; possibly, it is a marker for delayed cerebral maturation or it might be an expression of decreasing amount of extracerebral fluid.

Postnatal outcome of fetal isolated ventricular size disproportion in the absence of aortic coarctation

OBJECTIVE

Cardiac ventricular size disproportion is a marker for aortic coarctation (CoA) in fetal life, but approximately 50% of fetuses do not have CoA after birth. The aim of this study was to evaluate the postnatal outcome of cases with fetal ventricular size disproportion in the absence of CoA after birth.

METHODS

All cases with fetal isolated ventricular size disproportion diagnosed between 2002 and 2015 were extracted from a prenatal congenital heart defects regional registry. Cases were stratified according to presence or absence (non-CoA) of aortic arch anomalies after birth. Postnatal outcome of non-CoA cases was evaluated by assessing the presence of cardiac and other congenital malformations, genetic syndromes and other morbidity after birth. Non-CoA cases were further classified according to whether they had cardiovascular pathology requiring medication or intervention.

RESULTS

Seventy-seven cases with fetal ventricular size disproportion were identified, of which 46 (60%) did not have CoA after birth. Of these, 35 did not require cardiovascular intervention or medication, whereas 11 did. Of the 46 non-CoA cases, six presented with clinical pulmonary hypertension requiring treatment after birth, cardiac defects were present in 24 cases and syndromic features were seen in four. Overall, 43% of all non-CoA children were still under surveillance at the end of the study period.

CONCLUSIONS

The postnatal course of cases with fetal ventricular size disproportion is complicated by prenatally undetected congenital defects (46%) and pulmonary or transition problems (35%) in a significant number of cases that do not develop CoA. Proper monitoring of these cases is therefore warranted and it is advisable to incorporate the risks for additional morbidity and neonatal complications in prenatal counseling. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Left ventricular dysfunction is associated with frequent premature ventricular complexes and asymptomatic ventricular tachycardia in children

AIMS

To assess the risk factors for left ventricular (LV) dysfunction in a paediatric population with idiopathic frequent premature ventricular contractions (PVCs) and asymptomatic ventricular tachycardias (VTs).

METHODS AND RESULTS

Paediatric patients with the diagnosis of idiopathic frequent PVCs and asymptomatic VTs were retrospectively evaluated. Frequent PVCs were defined as ≥5% on 24 h Holter recording. Left ventricular dysfunction was defined as a shortening fraction of ≤28%. Seventy-two children were identified. Six patients showed LV dysfunction at diagnosis [age 10 ± 7 years, 2 (33%) had symptoms such as syncope, palpitations, fatigue, and dizziness], and 66 showed normal LV function [age 8 ± 6 years, 22 (33%) with symptoms]. Patients with LV dysfunction had a higher percentage of PVCs on Holter recordings (47 ± 16 vs. 16 ± 11%, P = 0.006), higher prevalence of VT [5 (83%) vs. 27 (41%), P = 0.045] and sustained ventricular tachycardia (sVT) [3 (50%) vs. 4 (6%), P = 0.001], and a higher number of couplets [6 (100%) vs. 34 (52%), P = 0.030]. In patients with LV dysfunction, two responded to medication (Classes Ic and II) and five underwent ablation, of which one was unsuccessful. During follow-up, LV function normalized in five of six patients. In patients with a normal function, none developed LV dysfunction during the follow-up.

CONCLUSION

In children with idiopathic PVCs and asymptomatic VTs, development of LV dysfunction is associated with a higher burden of PVCs, the presence of sVTs, and couplets. Left ventricular dysfunction appears to be reversible if the burden of PVCs is decreased by medication or ablation.

Head growth in fetuses with isolated congenital heart defects: lack of influence of aortic arch flow and ascending aorta oxygen saturation

OBJECTIVES

Congenital heart defects (CHDs) are reported to be associated with a smaller fetal head circumference (HC) and neurodevelopmental delay. Recent studies suggest that altered intrauterine brain hemodynamics may explain these findings. Our objectives were to evaluate the pattern of head growth in a large cohort of fetuses with various types of CHD, analyze these patterns according to the type of CHD and estimate the effect of cerebral hemodynamics with advancing gestation in the second and third trimesters.

METHODS

Singleton fetuses with an isolated CHD were selected from three fetal medicine units (n = 436). Cases with placental insufficiency or genetic syndromes were excluded. CHD types were clustered according to the flow and oxygen saturation in the aorta. Z-scores of biometric data were constructed using growth charts of a normal population. HC at different gestational ages was evaluated and univariate and multivariate mixed regression analyses were performed to examine the patterns of prenatal HC growth.

RESULTS

Fetuses with severe and less severe types of CHD demonstrated statistically significant HC growth restriction with increasing gestational age (slope of -0.017/day); however, there was no statistically significant effect of fetal hemodynamics on HC growth. Fetuses with CHD but normal brain oxygenation and normal aortic flow showed a significant decrease in HC growth (slope of -0.024/day). Only fetuses with isolated tetralogy of Fallot demonstrated a smaller HC z-score at 20 weeks of gestation (-0.67 (95% CI, -1.16 to -0.18)).

CONCLUSIONS

Despite the decline in head growth in fetuses with a prenatally detected isolated CHD, HC values were within the normal range, raising the question of its clinical significance. Furthermore, in contrast to other studies, this large cohort did not establish a significant correlation between aortic flow or oxygen saturation and HC growth. Factors other than altered fetal cerebral hemodynamics may contribute to HC growth restriction with increasing gestational age, such as (epi)genetic or placental factors. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Prenatal diagnosis of congenital heart defects: accuracy and discrepancies in a multicenter cohort

OBJECTIVE

To examine the accuracy of fetal echocardiography in diagnosing congenital heart disease (CHD) at the fetal medicine units of three tertiary care centers.

METHODS

This was a multicenter cohort study of tertiary echocardiography referrals between 2002 and 2012. Prenatal and postnatal diagnoses were compared and the degree of agreement was classified as 'correct' (anatomy correct and the postnatal diagnosis led to a similar outcome as expected), 'discrepant' (anatomical discrepancies present but the severity and prognosis of the defect were diagnosed correctly) or 'no similarity' (the pre- and postnatal diagnoses differed completely).

RESULTS

We included 708 cases with CHD for which both prenatal and postnatal data were available. The prenatal diagnosis was correct in 82.1% of cases and discrepancies present were present in 9.9%; however, these did not result in a different outcome. In 8.1% there was no similarity between prenatal and postnatal diagnoses. Disagreement between pre- and postnatal diagnoses occurred significantly more frequently in cases that presented with a normal four-chamber view than in those with an abnormal four-chamber view (5.5% vs 1.9%). Incorrect identification of the outflow tracts and incorrect differentiation between unbalanced atrioventricular septal defect and hypoplastic left heart syndrome were relatively commonly encountered. In many cases with disagreement, trisomy 21, extracardiac anomaly or a high maternal body mass index was present.

CONCLUSIONS

The prenatal diagnosis and estimated prognosis of fetal echocardiography in our tertiary referral centers were appropriate in 92% of cases. Some types of CHD remain difficult to diagnose or rule-out prenatally, therefore awareness and education are of considerable importance. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Prenatal detection of transposition of the great arteries reduces mortality and morbidity

OBJECTIVES

To evaluate the prenatal detection of transposition of the great arteries (TGA), after the introduction of a Dutch screening program in 2007, as well as the effect of prenatal detection on pre- and postsurgical mortality and morbidity.

METHODS

In a geographical cohort study, all infants with TGA who were born between 1 January 2002 and 1 January 2012 were included. The cases were divided into two groups: those with and those without a prenatal diagnosis. Pre- and postsurgical mortality was assessed, with a follow-up of 1 year. Presurgical morbidity was assessed in terms of cardiovascular compromise, metabolic acidosis, renal and/or hepatic dysfunction and closure of the duct before initiation of therapy.

RESULTS

Of all cases (n = 144), 26.4% were diagnosed prenatally, with detection rates of 15.7% and 41.0% in the first and last 5 years of the study period, respectively. First-year mortality was significantly lower in cases with a prenatal diagnosis of TGA than in those without (0.0% vs 11.4%, respectively). Presurgical mortality (4.9%) only occurred in undetected simple TGA cases. Closure of the duct before treatment, renal dysfunction and hypoxia occurred significantly more often in the group without a prenatal diagnosis.

CONCLUSIONS

The prenatal detection rate of TGA has increased significantly since the introduction of the screening program in 2007. Prenatal diagnosis is an important factor that contributes to survival of the infant in the first postnatal year. Furthermore, some morbidity indicators were significantly higher in the group without a prenatal diagnosis. These results justify efforts to improve prenatal screening programs.

Prenatal detection of congenital heart disease--results of a national screening programme

OBJECTIVE

Congenital heart disease (CHD) is the most common congenital malformation and causes major morbidity and mortality. Prenatal detection improves the neonatal condition before surgery, resulting in less morbidity and mortality. In the Netherlands a national prenatal screening programme was introduced in 2007. This study evaluates the effects of this screening programme.

DESIGN

Geographical cohort study.

SETTING

Large referral region of three tertiary care centres.

POPULATION

Fetuses and infants diagnosed with severe CHD born between 1 January 2002 and 1 January 2012.

METHODS

Cases were divided into two groups: before and after the introduction of screening.

MAIN OUTCOME MEASURES

Detection rates were calculated.

RESULTS

The prenatal detection rate (n = 1912) increased with 23.9% (95% confidence interval [95% CI] 19.5-28.3) from 35.8 to 59.7% after the introduction of screening and of isolated CHD with 21.4% (95% CI 16.0-26.8) from 22.8 to 44.2%. The highest detection rates were found in the hypoplastic left heart syndrome, other univentricular defects and complex defects with atrial isomerism (>93%). Since the introduction of screening, the 'late' referrals (after 24 weeks of gestation) decreased by 24.3% (95% CI 19.3-29.3).

CONCLUSIONS

This is the largest cohort study to investigate the prenatal detection rate of severe CHD in an unselected population. A nationally organised screening has resulted in a remarkably high detection rate of CHD (59.7%) compared with earlier literature.

The effect of exercise training on cardiac remodelling in children and young adults with corrected tetralogy of Fallot or Fontan circulation: a randomized controlled trial

BACKGROUND

Exercise can improve physical fitness in children and adults with congenital heart disease. We hypothesized that exercise training would not lead to adverse cardiac remodelling in this population.

METHODS AND RESULTS

This multi-centre randomized controlled trial included children and young adults (10 to 25 years) with either corrected tetralogy of Fallot or Fontan circulation. The exercise-group was enrolled in a 12 week standardized aerobic dynamic exercise training program. The control-group continued their life-style and received care as usual. Both groups underwent cardiopulmonary exercise testing, cardiac magnetic resonance imaging (MRI), echocardiography and neurohormonal assessment, within 2 weeks before and 2 weeks after the intervention period. Fifty-six patients were randomized to the exercise-group and 37 to the control-group. We assessed changes between the pre- and the post-intervention period for the exercise group compared to the changes in the control-group. Peak load increased significantly in the exercise-group compared to the control-group (exercise-group 6.9 ± 11.8 W; control-group 0.8 ± 13.9 W; p=0.047). There were no adverse events linked to the study. Ventricular systolic parameters, cardiac dimensions and neurohormonal markers during follow-up did not change in patients allocated to the exercise-group and control-group. Although there were some isolated minor changes in inflow parameters, there was no consistent pattern of changes, indicating a lack of true change in the diastolic function.

CONCLUSION

We demonstrated that no clinically relevant adverse cardiac remodelling occurred after 12 weeks of exercise training in patients with either corrected tetralogy of Fallot or Fontan circulation.

CLINICAL TRIAL REGISTRATION

www.trialregister.nl, identification NTR2731.

Left cardiac sympathetic denervation in the Netherlands for the treatment of inherited arrhythmia syndromes

Introduction

Treating therapy-resistant patients with inherited arrhythmia syndromes can be difficult and left cardiac sympathetic denervation (LCSD) might be a viable alternative treatment option. We provide an overview of the indications and outcomes of LCSD in patients with inherited arrhythmia syndromes in the only tertiary referral centre in the Netherlands where LCSD is conducted in these patients.

Methods

This was a retrospective study, including all patients with inherited arrhythmia syndromes who underwent LCSD in our institution between 2005 and 2013. LCSD involved ablation of the lower part of the left stellate ganglion and the first four thoracic ganglia.

Results

Seventeen patients, 12 long-QT syndrome (LQTS) patients (71 %) and 5 catecholaminergic polymorphic ventricular tachycardia (CPVT) patients (29 %), underwent LCSD. Most patients (94 %) were referred because of therapy-refractory cardiac events. In 87 % the annual cardiac event rate decreased. However, after 2 years the probability of complete cardiac event-free survival was 59 % in LQTS and 60 % in CPVT patients. Two patients (12 %) had major non-reversible LCSD-related complications: one patient suffered from a Harlequin face post-procedure and one severely affected LQT8 patient died the day after LCSD due to complications secondary to an arrhythmic storm during the procedure.

Conclusion

LSCD for inherited arrhythmia syndromes, which is applied on a relatively small scale in the Netherlands, reduced the cardiac event rate in 87 % of the high-risk patients who had therapy-refractory cardiac events, while the rate of major complications was low. Therefore, LSCD seems a viable treatment for patients with inherited arrhythmia syndromes without other options for therapy.

Cardiac resynchronisation therapy in paediatric and congenital heart disease: differential effects in various anatomical and functional substrates

Background:

Cardiac resynchronisation therapy (CRT) is increasingly used in children in a variety of anatomical and pathophysiological conditions, but published data are scarce.

Objective:

To record current practice and results of CRT in paediatric and congenital heart disease.

Design:

Retrospective multicentre European survey.

Setting:

Paediatric cardiology and cardiac surgery centres.

Patients:

One hundred and nine patients aged 0.24–73.8 (median 16.9) years with structural congenital heart disease (n = 87), congenital atrioventricular block (n = 12) and dilated cardiomyopathy (n = 10) with systemic left (n = 69), right (n = 36) or single (n = 4) ventricular dysfunction and ventricular dyssynchrony during sinus rhythm (n = 25) or associated with pacing (n = 84).

Interventions:

CRT for a median period of 7.5 months (concurrent cardiac surgery in 16/109).

Main outcome measures:

Functional improvement and echocardiographic change in systemic ventricular function.

Results:

The z score of the systemic ventricular end-diastolic dimension decreased by median 1.1 (p<0.001). Ejection fraction (EF) or fractional area of change increased by a mean (SD) of 11.5 (14.3)% (p<0.001) and New York Heart Association (NYHA) class improved by median 1.0 grade (p<0.001). Non-response to CRT (18.5%) was multivariably predicted by the presence of primary dilated cardiomyopathy (p = 0.002) and poor NYHA class (p = 0.003). Presence of a systemic left ventricle was the strongest multivariable predictor of improvement in EF/fractional area of change (p<0.001). Results were independent of the number of patients treated in each contributing centre.

Conclusion:

Heart failure associated with ventricular pacing is the largest indication for CRT in paediatric and congenital heart disease. CRT efficacy varies widely with the underlying anatomical and pathophysiological substrate.

Development of the cardiac conduction system and the possible relation to predilection sites of arrhythmogenesis

The cardiac conduction system (CCS) encompasses a complex system responsible for the coordinated contraction of the heart. In the developing heart, as well as in the adult heart, tissues of the (putative) CCS are characterized by different properties than the surrounding working myocardium, which can be observed on a histological level, as well as by the expression patterns of several immunohistological and molecular markers. In recent years, many markers have been studied that have helped to elucidate the processes involved in CCS development. It has become clear that multiple genes, cells and their interactions are involved in this complex process. In this article, an overview of the current knowledge of CCS development is supplied. Furthermore, several controversies regarding conduction system development are discussed, as well as the possible significance of embryologic development of the CCS for the development of arrhythmias later in life.

[Treatment of foetal supraventricular tachycardia with antiarrhythmic medication administered through the umbilical vein]

Foetal supraventricular tachycardia (SVT) with hydrops foetalis is associated with a high morbidity and mortality rate. If SVT with hydrops foetalis persists despite transplacental therapy, direct foetal treatment can be initiated. One foetus was found to have SVT with hydrops foetalis during the 29th week of pregnancy, and the condition persisted despite transplacental treatment. Amiodarone was administered directly via the umbilical vein, and the SVT resolved. A second foetus was found to have SVT with hydrops foetalis during the 28th week of pregnancy. The condition persisted despite maternal antiarrhythmic medication. Direct treatment of the foetus with amiodarone was successful. Amiodarone is the treatment of choice for direct foetal therapy for SVT, and can be administered safely via the umbilical vein. Direct foetal therapy should be considered for the treatment of foetal SVT with hydrops foetalis that occurs in the first 31 weeks of pregnancy and persists despite adequate transplacental therapy.

[Percutaneous implantation of a pulmonary valve in 3 children with surgically corrected cardiac anomalies]

An 11-year-old girl, a 15-year-old boy and a 12-year-old girl all underwent percutaneous implantation of a Melody pulmonary valve prosthesis to replace a stenotic and insufficient homograft in the pulmonary artery. Preoperatively, 2 of the children suffered from fatigue and dyspnoea on exertion The homografts had been implanted between the ages of 1-2, to establish surgical continuity between the right ventricle and the pulmonary artery. The anomalies were tetralogy of Fallot, pulmonary atresia with intact ventricular septum and pulmonary atresia with a ventricular septum defect. Percutaneous pulmonary valve replacement was successful in all 3 patients. After implantation, right ventricular pressure decreased to 30% of systemic pressure and regurgitation was not observed. All patients were discharged in a good condition on the day after the implantation. Percutaneous pulmonary valve replacement is a promising technique with good short-term results. In selected patients this percutaneous technique can substitute or postpone the surgical replacement ofa stenotic or insufficient homograft.

[Favourable results with surgical treatment in 43 children with hypoplastic left-heart syndrome or similar disorders, 1999-2005]

OBJECTIVE

To describe the results of surgical treatment of hypoplastic left-heart syndrome (HLHS) and HLHS-like disorders in the Amsterdam-Leiden Centre for Congenital Heart Disease, the Netherlands.

DESIGN

Retrospective, descriptive.

METHOD

Data were collected on 43 neonates with HLHS or similar disorders who underwent surgical treatment between December 1999 and December 2005. HLHS was present in 37 patients and 6 had disorders similar to HLHS (unbalanced atrioventricular septal defect, truncus arteriosus with hypoplastic left ventricle, double inlet left ventricle). Surgery was performed in 3 steps: Norwood operation shortly after birth (n = 43), bidirectional cavopulmonary anastomosis a few months later (n = 30) and total cavopulmonary connection at the age of 2-3 years (n = 10). During the Norwood operation, the first 21 patients received a modified Blalock shunt (between the right brachiocephalic artery and pulmonary artery), whereas the following 22 patients received a Sano shunt (between the right ventricle and pulmonary artery).

RESULTS

Of the 43 patients, 11 died: 7 within 30 days of the first operation, 2 between the first and second operation, and 2 between the second and third operation. Actuarial survival for the entire group is 74% (32/43). The mortality rate was lower with the Sano shunt (9%; 2/22) than with the modified Blalock shunt (43%; 9/21). Catheter interventions were necessary in 10 patients: 6 had balloon dilatation of the distal aortic arch and 4 had balloon dilatation/stent placement for narrowed pulmonary arteries. With a median follow-up of 22 months (range: 1-75), 2 patients had marked neurological side effects. All 32 surviving patients were in good clinical condition.

Morphogenetic differences of secundum atrial septal defects

It is generally considered that the development of secundum atrial septal defect (ASDII) or oval fossa defect is the result of excessive resorption of the embryological atrial septum primum, but this does not seem to explain all defects. We investigated 58 postmortem hearts with an ASDII and 22 normal hearts from patients ranging in age from 1 day to 49 years. The different structures of the oval fossa were examined. In 86% of the specimens, the defects were the result of a malformation of the valvula foraminis ovalis or embryological atrial septum primum, and in 14% an absent superior limbus (septum secundum) was the cause of the interatrial communication. The "septum primum" ASDs were divided into four subgroups based on the degree of deficiency of the septum primum and position of the ostium secundum within the septum primum. We conclude that the morphogenesis of ASDII is variable and both septum primum and septum secundum defects occur, which may be relevant in view of genetic studies that may lead to further differentiation of patients with and without genetically determined ASDIIs.

[Radiofrequency catheter ablation for treating children with cardiac arrhythmias: favourable results after a mean of 4 years]

OBJECTIVE

Analysis of long-term results with radiofrequency catheter ablation (RF ablation) in children.

DESIGN

Retrospective.

METHOD

Data were analysed from all 118 paediatric patients < or =18 years old who underwent RF ablation at the Leiden University Medical Centre (LUMC), the Netherlands, during the period 1 December 1992-31 May 2004.

RESULTS

The group consisted of 6o boys and 58 girls with a mean age of 12.7 years (SD: 4.6). They underwent 140 RF ablation procedures for 122 disorders. Indications for RF ablation were: failure or side-effects of antiarrhythmic medication (45%), patient/parent choice (45%), cardiomyopathy or life-threatening arrhythmia (8%), and impending surgery for a congenital heart defect (2%). The mean follow-up interval was 4 years (SD: 3.2; range: 1.2 months-11.3 years). The final total success rate for RF was 93% (n = 110). 19 patients (16%) underwent a total of 22 repeat procedures. Recurrences occurred after a mean period of 2.3 months (SD: 2.5) following successful RF ablation. Major complications (2nd degree AV block) occurred in 2 patients. During follow-up, no evidence was found of new arrhythmias or of coronary artery lesion development as the result ofRF ablation. There was no difference between the < 10 years of age group and the > or = 10 years of age group in terms of final success rate (93% vs. 93%; p = 0.914) and complication rate (3% vs. 7%, p = 0.680).

CONCLUSION

The long-term outcome of paediatric patients who underwent RF ablation was good. RF ablation in young children (< 10 years) was found to be safe and effective. These results demonstrate that it is also possible to curatively treat this group of patients with RF ablation in specialized centres.

Development of the Right Ventricular Inflow Tract and Moderator Band

Atriofascicular accessory bundles with AV-node like conduction properties can sustain atrioventricular (AV) re-entrant tachycardia (Mahaim tachycardia). During early embryogenesis, the AV canal is situated above the primitive left ventricle (LV), and a right AV connection has not been achieved yet. We studied the formation of the right ventricular (RV) inflow tract in relation to the developing cardiac conduction system and hypothesized a morphological explanation for functional atriofascicular bypass tracts. Analysis of lacZ-expression during sequential stages of cardiogenesis was performed in CCS-lacZ transgenic mice (E9.5 to 15.5). Embryos were stained for β-galactosidase activity and the myocardial marker HHF35. At early stages CCS-lacZ expression was observed in a ring surrounding the AV canal, which connected at the inner curvature to the primary fold. The first sign of formation of the (CCS-lacZ negative) RV inlet component was a groove in the CCS-lacZ positive tissue of the primary fold. Outgrowth of the RV inlet tract resulted in division of the primary fold in a septal part, the trabecula septomarginalis and a lateral part, the moderator band, which extended laterally up to the right AV ring. Electrophysiological measurements in embryonic hearts (E15.5) in which the right atrium (RA) and RV were isolated from the left atrium (LA) and LV supported the functionality of this AV-connection via the moderator band, by demonstrating sequential atrial and ventricular activation in both RA/RV and LA/LV preparations. In conclusion, our observations may provide a possible morphological and functional explanation for atriofascicular accessory pathways via the moderator band, underlying Mahaim tachycardia.

[Percutaneous closure of a perimembraneous ventricular septal defect: the first 4 patients in The Netherlands]

In four female patients, aged 30, 10, 8 and 2 years and 9 months (the latter with Down's syndrome), all with a perimembranous ventricular septal defect (VSD), percutaneous closure of the VSD was carried out using an Amplatzer endoprosthesis. These were the first 4 patients to undergo this procedure in The Netherlands. In 3 of the patients the procedure was without complications and complete occlusion of the defects was achieved. The last patient developed a left anterior hemiblock after implantation of the device and one week later an intermittent second degree atrioventricular block was detected, for which a pacemaker was implanted. A few days later the atrioventricular conduction time returned to normal. There was complete occlusion of the defect. Percutaneous closure of a perimembranous VSD using an Amplatzer prosthesis is a promising technique with good short-term results. In a selected group of patients this new technique can replace surgical treatment.

[Tachypnoea and dyspnoea in two infants due to dilated cardiomyopathy associated with an anomalous origin of the left coronary artery]

Two infants were referred to the emergency ward: a 3.5-month-old male infant in whom sweating and shortness of breath were seen during drinking and crying, and a 5-week-old girl that had drunk less the past day, moaned while breathing for the past few hours and had become increasingly drowsy. They were not suffering from an infection but from a dilated cardiomyopathy based on an anomalous origin of the left coronary artery from the pulmonary artery. The left coronary artery was then implanted in the aorta surgically. Both patients recovered well. Airway tract infection and sepsis are obvious common differential diagnostic considerations when confronted with a tachy-dyspnoeic infant. However, a cardiac cause, such as a dilated cardiomyopathy with cardiac decompensation, must also be considered as the presentation can be similar. The abnormal origin of the left coronary artery from the pulmonary artery is one of the few readily well treatable causes.

99mTc-MIBI myocardial perfusion imaging in myocarditis

Myocardial perfusion imaging with technetium-99m-labelled methoxyisobutyl isonitrile single photon emission computed tomography (99mTc-MIBI SPECT) has proven to be an important clinical procedure in assessing the severity of myocardial ischaemia. The uptake and clearance of 99mTc-MIBI by the myocardium is affected by cell viability and membrane integrity. Consequently, infectious diseases, such as myocarditis, may also affect myocardial perfusion by inducing local inflammation and necrosis. We compared 99mTc-MIBI myocardial perfusion imaging with other heart monitoring methods in order to assess its value in the diagnosis of children with Coxsackie viral myocarditis. We examined 46 patients (age, 3-12 years) with Coxsackie viral myocarditis using 99mTc-MIBI myocardial perfusion imaging and compared the perfusion data with myocardial enzymes, electrocardiographic findings and echocardiography. Regions of hypoperfusion were found in all 46 patients. Seventeen patients (37%) showed two or more areas of diminished perfusion. Myocardial hypoperfusion was mild-to-moderate (<30%) in 33 (72%) patients and severe (>30%) in 13 (28%) patients. Characteristic creatine-kinase isoenzyme (CK-MB) increases, ST-T segment changes and diminished heart function were significantly correlated with reduced myocardial perfusion (all comparisons P<0.05). The results of this study suggest that the presence of myocardial uptake of 99mTc-MIBI may be a marker of myocardial inflammation and necrosis. All 46 patients with Coxsackie viral myocarditis showed a certain degree of reduced perfusion. When the perfusion findings were compared with other parameters, it was shown that myocardial enzyme levels, ST-T segment changes and left ventricular function correlated well with the 99mTc-MIBI-established perfusion defect severity. 99mTc-MIBI SPECT imaging is therefore helpful in providing additional diagnostic information in patients with Coxsackie viral myocarditis.

Detection of malignant right coronary artery anomaly by multi-slice CT coronary angiography

Coronary artery anomalies occur in 0.3-0.8% of the population and infer a high risk for sudden cardiac death in young adults. Diagnosis is usually established during coronary angiography, which is hampered by poor spatial visualization. Magnetic resonance imaging is an alternative, but it is not feasible in the presence of metal objects or claustrophobia. In this report, a 15-year-old boy experienced ventricular fibrillation and was successfully resuscitated. Cardiac catheterization was inconclusive, and pacemaker implantation prohibited the use of MR imaging. Multi-slice CT coronary angiography revealed a malignant anomalous right coronary artery.

Prediction of human protein function from post-translational modifications and localization features

We have developed an entirely sequence-based method that identifies and integrates relevant features that can be used to assign proteins of unknown function to functional classes, and enzyme categories for enzymes. We show that strategies for the elucidation of protein function may benefit from a number of functional attributes that are more directly related to the linear sequence of amino acids, and hence easier to predict, than protein structure. These attributes include features associated with post-translational modifications and protein sorting, but also much simpler aspects such as the length, isoelectric point and composition of the polypeptide chain.

[Good results after closure of a arterial septal defect during heart catheterisation instead of surgery]

OBJECTIVE

Evaluation of the first results in the Netherlands of percutaneous and transvenous closure of an ASD II in children with an Amplatzer Septal Occluder (ASO).

DESIGN

Prospective.

METHOD

Data were collected from children with an ASD II prior to, during and up to 24 months after the insertion of an ASO during heart catheterisation in Leiden University Hospital, the Netherlands.

RESULTS

Between 1 January 1998 and 29 February 2000, 28 patients (12 girls, 16 boys; mean age: 74 months (range: 15-198 months)) underwent heart catheterisation to close an ASD II with an ASO. In 26 patients an ASO could be placed without significant complications. The size of the device varied from 9-34 mm (median 16 mm). In one patient ASD closure was not attempted because of multiple ASDs. In another patient the procedure was stopped after air embolism into the coronary arteries had occurred during preparation of ASO implantation. In 23/26 patients with an implanted ASO, no residual shunt was present after 24 hours. One child, in whom the defect was found to be closed after 24 hours and after three weeks, returned abroad and was lost to follow-up. After one year all defects (n = 22) were completely closed.

CONCLUSION

Percutaneous transvenous closure of an ASD II with an ASO was possible, was not associated with any significant complications and had a high success rate, even in relatively young children with large defects.

Three-dimensional distribution of bipolar atrial electrogram voltages in patients with congenital heart disease

Voltage differences might be used to distinguish normal atrial tissue from abnormal atrial tissue. This study was aimed at identifying lowest voltage areas in patients with atrial tachycardia after surgical correction of congenital heart disease and to evaluate if identification of these areas in diseased hearts facilitates selection of critical conduction pathways in reentrant circuits as target sites for catheter ablation. Ten patients (four men, age 39 +/- 15 years) with normal sized atria and atrioventricular reciprocating tachycardia (control group) and ten patients (5 men, 32 +/- 7 years) with congenital heart disease and postoperative atrial tachycardia (CL 281 +/- 79 ms) referred for radiofrequency catheter ablation were studied. Mapping and ablation was guided by a three-dimensional electroanatomic mapping system (CARTO) in all patients. In the control group, voltage maps were constructed during sinus rhythm and during tachycardia to evaluate the voltage distribution. The amplitude of bipolar signals was 1.90 +/- 1.45 mV (0.11-8.12 mV, n = 660) during sinus rhythm and 1.45 +/- 1.66 mV (0.12-5.83 mV, n = 440, P < 0.05) during atrioventricular reciprocating tachycardia. In the study group, the amplitude of 1,962 bipolar signals during tachycardia was 1.01 +/- 1.19 mV (0.04-9.40 mV), which differed significantly from the control group during tachycardia (P < 0.0001). No significant difference in the tachycardia cycle length was found (P < 0.05) between the control and study groups. As the lowest voltage measured in normal hearts was 0.1 mV, this value was used as the upper limit of the lowest voltage areas in the patients with congenital heart disease. These areas were identified by detailed voltage mapping and represented by a gray color. Activation and propagation maps were then used to select critical conduction pathways as target sites for ablation. These sites were characterized by fragmented signals in all patients. Ablation resulted in termination of the tachycardia in eight (80%) of ten patients. Complications were not observed. Identification of the lowest voltage areas using a cut-off value of 0.1 mV in congenital heart disease patients with postoperative atrial reentrant tachycardia facilitated the selection of critical conduction pathways as target sites for ablation.

Uptake of pp65 in in vitro generated pp65-positive polymorphonuclear cells mediated by phagocytosis and cell fusion?

OBJECTIVE

The cytomegalovirus (CMV) antigenemia consists of the detection of CMV pp65 in the nucleus of polymorphonuclear granulocytes (PMN), but it is unclear where and how PMN pick up virus particles or proteins. In an in vitro model for CMV antigenemia we investigated the mechanism of pp65 uptake by PMN that results in its expression in the nucleus.

METHODS

A series of inhibitors of different mechanisms was used to study the uptake of pp65 by PMN during coculture with CMV-infected endothelial cells and we performed a morphological analysis by light and transmission electron microscopy.

RESULTS

Nocodazole and cytochalasin B inhibited uptake of pp65 by PMN with 59.4 +/- 14.1 and 73.3 +/- 12.7%, respectively. The presence of anti-CMV hyperimmune globulin or lactoferrin during coculture reduced the number of pp65-positive PMN with 45.8 +/- 7.0 or 40.6 +/- 3.2%. Furthermore, a small number of the pp65-positive PMN obtained after coculture had fused to large cells with multilobed nuclei. PMN were observed that enclosed viral particles as well as free viral particles containing PMN in the cytoplasm.

CONCLUSION

Fusion of viral particles with PMN and phagocytosis are both involved in the uptake of pp65.

Implantation of cardioverter device in young children: the perirenal approach

Placement of Implantable cardioverter devices in young children is complicated because of the relatively large size and heavy weight of these devices. A technique is described where the device is implanted in the left perirenal space while an endovascular lead is used instead of an epicardial patch electrode.

Ultrastructural morphology and localisation of cisplatin-induced platinum-DNA adducts in a cisplatin-sensitive and -resistant human small cell lung cancer cell line using electron microscopy

Ultrastructural morphology (transmission electron microscopy) and localisation of cisplatin-induced platinum (Pt)-DNA adducts (immunoelectron microscopy) were analysed in the human small cell lung cancer cell line GLC(4) and its 40-fold in vitro acquired cisplatin-resistant subline GLC(4)-CDDP, which is characterised by, among other things, a decreased DNA platination. Immunolabelling of Pt-DNA adducts was performed with the polyclonal antibody GPt, known to detect the main Pt-containing intrastrand and interstrand DNA adducts. Morphological analysis of GLC(4) and GLC(4)-CDDP at the ultrastructural level showed cells with a high nucleus/cytoplasm ratio with the majority of nuclei containing one or more nucleoli. GLC(4)-CDDP showed, in contrast to GLC(4), an extensive Golgi apparatus and an increased number of mitochondria. DNA platination was detectable in both GLC(4) and GLC(4)-CDDP. Immunoelectron microscopy showed Pt-DNA adducts primarily in the nucleus, preferentially at loci with high-density chromatin (e.g. heterochromatin, pars granulosa around nucleoli, condensed DNA in proliferating and apoptotic cells), and in mitochondria. The level of detectable Pt-DNA adducts was cell cycle status-dependent. In both cell lines, Pt-DNA adduct levels increased from non-dividing interphase cells to dividing cells and were highest in cells undergoing apoptosis. Overall localisation of Pt-DNA adducts was comparable in GLC(4) and GLC(4)-CDDP cells.

Normal development of the pulmonary veins in human embryos and formulation of a morphogenetic concept for sinus venosus defects

A sinus venosus defect is a form of interatrial communication associated with abnormal drainage of the right pulmonary veins. Its morphogenesis still remains unclear. We therefore studied the normal development of pulmonary veins in human embryos in relation to the sinus venosus and the dorsal mesocardium using graphic reconstructions and HNK-1 immunohistochemistry. Twenty embryos, ranging from 4 to 7 weeks' gestation, were examined. At 4 weeks, the orifice of the nonlumenized common pulmonary vein is visible as an endothelial invagination within the sinus venosus segment. Development of the muscular septum primum and the ventral proliferation of extracardiac mesenchyme from the dorsal mesocardium positions the common pulmonary vein (CPV) eventually into the left atrium. The right wall of the CPV contributes to the posterior part of the atrial septum and is continuous with the dorsal sinuatrial fold (the future left venous valve). With the use of HNK-1 antigen expression as a marker for sinus venosus myocardium, this common wall between the right-sided sinus venosus and the CPV is demonstrated, and at 7 weeks the proximal part of the right upper pulmonary vein also becomes part of this common wall. This study demonstrates that the CPV develops within the sinus venosus segment and that later a common myocardial wall is present between the sinus venosus in the right atrium and the CPV. A deficiency of this wall explains the development of sinus venosus defects.

In vivo protection of nigral dopamine neurons by lentiviral gene transfer of the novel GDNF-family member neublastin/artemin

The glial cell line-derived neurotrophic factor (GDNF)-family of neurotrophic factors consisted until recently of three members, GDNF, neurturin, and persephin. We describe here the cloning of a new GDNF-family member, neublastin (NBN), identical to artemin (ART), recently published (Baloh et al., 1998). Addition of NBN/ART to cultures of fetal mesencephalic dopamine (DA) neurons increased the number of surviving tyrosine hydroxylase (TH)-immunoreactive neurons by approximately 70%, similar to the maximal effect obtained with GDNF. To investigate the neuroprotective effects in vivo, lentiviral vectors carrying the cDNA for NBN/ART or GDNF were injected into the striatum and ventral midbrain. Three weeks after an intrastriatal 6-hydroxydopamine lesion only about 20% of the nigral DA neurons were left in the control group, while 80-90% of the DA neurons remained in the NBN/ART and GDNF treatment groups, and the striatal TH-immunoreactive innervation was partly spared. We conclude that NBN/ART, similarly to GDNF, is a potent neuroprotective factor for the nigrostriatal DA neurons in vivo.