Clinical phenotype of FOXP1 syndrome: parent-reported medical signs and symptoms in 40 individuals

BACKGROUND

The first studies on patients with forkhead-box protein P1 (FOXP1) syndrome reported associated global neurodevelopmental delay, autism symptomatology, dysmorphic features and cardiac and urogenital malformations. The aim of this study was to assess the prevalence of congenital abnormalities in an unbiased cohort of patients with FOXP1 syndrome and to document rare complications.

METHODS

Patients with FOXP1 syndrome were included, mostly diagnosed via whole-exome sequencing for neurodevelopmental delay. A parent-report questionnaire was used to assess medical signs and symptoms, including questions about features rated as most burdensome by patients and their family.

RESULTS

Forty individuals were included, 20 females and 20 males. The mean age at assessment was 13.2 years (median 8.5 years; range 2-54 years; ≥18 years n = 7). Seven adults were included. All patients had developmental problems, including cognitive, communication, social-emotional and motor delays. The most prevalent medical signs and symptoms include delayed bladder control, sleeping problems, hypermetropia, strabismus, sacral dimple, undescended testes, abnormal muscle tone and airway infections. The most burdensome complaints for patients with FOXP1 syndrome, as perceived by parents, include intellectual disability, impaired communication, behaviour problems, lack of age-appropriate self-reliance, attention problems and anxiety. According to parents, patients have quite similar reported symptoms, although incontinence, obsessions and a complex sensory profile have a higher ranking.

CONCLUSION

The results of this study may be used to further guide medical management and identify patient priorities for future research targeted on those features of FOXP1 syndrome that most impair quality of life of patients and their families.

The arrhythmogenic cardiomyopathy phenotype associated with PKP2 c.1211dup variant

BACKGROUND

The arrhythmogenic cardiomyopathy (ACM) phenotype, with life-threatening ventricular arrhythmias and heart failure, varies according to genetic aetiology. We aimed to characterise the phenotype associated with the variant c.1211dup (p.Val406Serfs*4) in the plakophilin‑2 gene (PKP2) and compare it with previously reported Dutch PKP2 founder variants.

METHODS

Clinical data were collected retrospectively from medical records of 106 PKP2 c.1211dup heterozygous carriers. Using data from the Netherlands ACM Registry, c.1211dup was compared with 3 other truncating PKP2 variants (c.235C > T (p.Arg79*), c.397C > T (p.Gln133*) and c.2489+1G > A (p.?)).

RESULTS

Of the 106 carriers, 47 (44%) were diagnosed with ACM, at a mean age of 41 years. By the end of follow-up, 29 (27%) had experienced sustained ventricular arrhythmias and 12 (11%) had developed heart failure, with male carriers showing significantly higher risks than females on these endpoints (p < 0.05). Based on available cardiac magnetic resonance imaging and echocardiographic data, 46% of the carriers showed either right ventricular dilatation and/or dysfunction, whereas a substantial minority (37%) had some form of left ventricular involvement. Both geographical distribution of carriers and haplotype analysis suggested PKP2 c.1211dup to be a founder variant originating from the South-Western coast of the Netherlands. Finally, a Cox proportional hazards model suggested significant differences in ventricular arrhythmia-free survival between 4 PKP2 founder variants, including c.1211dup.

CONCLUSIONS

The PKP2 c.1211dup variant is a Dutch founder variant associated with a typical right-dominant ACM phenotype, but also left ventricular involvement, and a possibly more severe phenotype than other Dutch PKP2 founder variants.

Combining Congenital Heart Surgical and Interventional Cardiology Outcome Data in a Single Database: The Development of a Patient-Centered Collaboration of the European Congenital Heart Surgeons Association (ECHSA) and the Association for European Paediatric and Congenital Cardiology (AEPC)

The European Congenital Heart Surgeons Association (ECHSA) Congenital Database (CD) is the second largest clinical pediatric and congenital cardiac surgical database in the world and the largest in Europe, where various smaller national or regional databases exist. Despite the dramatic increase in interventional cardiology procedures over recent years, only scattered national or regional databases of such procedures exist in Europe. Most importantly, no congenital cardiac database exists in the world that seamlessly combines both surgical and interventional cardiology data on an international level; therefore, the outcomes of surgical and interventional procedures performed on the same or similar patients cannot easily be tracked, assessed, and analyzed. In order to fill this important gap in our capability to gather and analyze information on our common patients, ECHSA and The Association for European Paediatric and Congenital Cardiology (AEPC) have embarked on a collaborative effort to expand the ECHSA-CD with a new module designed to capture data about interventional cardiology procedures. The purpose of this manuscript is to describe the concept, the structure, and the function of the new AEPC Interventional Cardiology Part of the ECHSA-CD, as well as the potentially valuable synergies provided by the shared interventional and surgical analyses of outcomes of patients. The new AEPC Interventional Cardiology Part of the ECHSA-CD will allow centers to have access to robust surgical and transcatheter outcome data from their own center, as well as robust national and international aggregate outcome data for benchmarking. Each contributing center or department will have access to their own data, as well as aggregate data from the AEPC Interventional Cardiology Part of the ECHSA-CD. The new AEPC Interventional Cardiology Part of the ECHSA-CD will allow cardiology centers to have access to aggregate cardiology data, just as surgical centers already have access to aggregate surgical data. Comparison of surgical and catheter interventional outcomes could potentially strengthen decision processes. A study of the wealth of information collected in the database could potentially also contribute toward improved early and late survival, as well as enhanced quality of life of patients with pediatric and/or congenital heart disease treated with surgery and interventional cardiac catheterization across Europe and the world.

Combining Congenital Heart Surgical and Interventional Cardiology Outcome Data in a Single Database: The Development of a Patient-Centered Collaboration of the European Congenital Heart Surgeons Association (ECHSA) and the Association for European Paediatric and Congenital Cardiology (AEPC)

The European Congenital Heart Surgeons Association (ECHSA) Congenital Database (CD) is the second largest clinical pediatric and congenital cardiac surgical database in the world and the largest in Europe, where various smaller national or regional databases exist. Despite the dramatic increase in interventional cardiology procedures over recent years, only scattered national or regional databases of such procedures exist in Europe. Most importantly, no congenital cardiac database exists in the world that seamlessly combines both surgical and interventional cardiology data on an international level; therefore, the outcomes of surgical and interventional procedures performed on the same or similar patients cannot easily be tracked, assessed, and analyzed. In order to fill this important gap in our capability to gather and analyze information on our common patients, ECHSA and The Association for European Paediatric and Congenital Cardiology (AEPC) have embarked on a collaborative effort to expand the ECHSA-CD with a new module designed to capture data about interventional cardiology procedures. The purpose of this manuscript is to describe the concept, the structure, and the function of the new AEPC Interventional Cardiology Part of the ECHSA-CD, as well as the potentially valuable synergies provided by the shared interventional and surgical analyses of outcomes of patients. The new AEPC Interventional Cardiology Part of the ECHSA-CD will allow centers to have access to robust surgical and transcatheter outcome data from their own center, as well as robust national and international aggregate outcome data for benchmarking. Each contributing center or department will have access to their own data, as well as aggregate data from the AEPC Interventional Cardiology Part of the ECHSA-CD. The new AEPC Interventional Cardiology Part of the ECHSA-CD will allow cardiology centers to have access to aggregate cardiology data, just as surgical centers already have access to aggregate surgical data. Comparison of surgical and catheter interventional outcomes could potentially strengthen decision processes. A study of the wealth of information collected in the database could potentially also contribute toward improved early and late survival, as well as enhanced quality of life of patients with pediatric and/or congenital heart disease treated with surgery and interventional cardiac catheterization across Europe and the world.

Delayed biventricular repair of interrupted aortic arch with left ventricular outflow tract obstruction in 22q11.2 deletion syndrome: a case report

In patients with critical left ventricular outflow tract obstruction but adequately sized ventricles, the treatment of choice is biventricular repair. Several options have been proposed, including neonatal Yasui or Ross-Konno operation. However, each of these procedures carries a high mortality risk, especially in syndromic neonates. Here, we report the case of a patient with 22q11.2 deletion syndrome and a diagnosis of interrupted aortic arch type B2, ventricular septal defect and left ventricular outflow tract obstruction. As a means to avoid high-risk neonatal surgery in this patient, we pursued a strategy of delayed biventricular repair involving initial hybrid Norwood palliation followed by a Yasui-type operation at 3 months. Although this strategy turned out to be successful, proactive monitoring for the development of ductal stent stenosis during follow-up after the hybrid procedure remains crucial to prevent hemodynamic complications such as cardiac failure and systemic hypoperfusion.

Clinical Features and Natural History of Preadolescent Nonsyndromic Hypertrophic Cardiomyopathy

BACKGROUND

Up to one-half of childhood sarcomeric hypertrophic cardiomyopathy (HCM) presents before the age of 12 years, but this patient group has not been systematically characterized.

OBJECTIVES

The aim of this study was to describe the clinical presentation and natural history of patients presenting with nonsyndromic HCM before the age of 12 years.

METHODS

Data from the International Paediatric Hypertrophic Cardiomyopathy Consortium on 639 children diagnosed with HCM younger than 12 years were collected and compared with those from 568 children diagnosed between 12 and 16 years.

RESULTS

At baseline, 339 patients (53.6%) had family histories of HCM, 132 (20.9%) had heart failure symptoms, and 250 (39.2%) were prescribed cardiac medications. The median maximal left ventricular wall thickness z-score was 8.7 (IQR: 5.3-14.4), and 145 patients (27.2%) had left ventricular outflow tract obstruction. Over a median follow-up period of 5.6 years (IQR: 2.3-10.0 years), 42 patients (6.6%) died, 21 (3.3%) underwent cardiac transplantation, and 69 (10.8%) had life-threatening arrhythmic events. Compared with those presenting after 12 years, a higher proportion of younger patients underwent myectomy (10.5% vs 7.2%; P = 0.045), but fewer received primary prevention implantable cardioverter-defibrillators (18.9% vs 30.1%; P = 0.041). The incidence of mortality or life-threatening arrhythmic events did not differ, but events occurred at a younger age.

CONCLUSIONS

Early-onset childhood HCM is associated with a comparable symptom burden and cardiac phenotype as in patients presenting later in childhood. Long-term outcomes including mortality did not differ by age of presentation, but patients presenting at younger than 12 years experienced adverse events at younger ages.

Relationship Between Maximal Left Ventricular Wall Thickness and Sudden Cardiac Death in Childhood Onset Hypertrophic Cardiomyopathy

BACKGROUND

Maximal left ventricular wall thickness (MLVWT) is a risk factor for sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HCM). In adults, the severity of left ventricular hypertrophy has a nonlinear relationship with SCD, but it is not known whether the same complex relationship is seen in childhood. The aim of this study was to describe the relationship between left ventricular hypertrophy and SCD risk in a large international pediatric HCM cohort.

METHODS

The study cohort comprised 1075 children (mean age, 10.2 years [±4.4]) diagnosed with HCM (1-16 years) from the International Paediatric Hypertrophic Cardiomyopathy Consortium. Anonymized, noninvasive clinical data were collected from baseline evaluation and follow-up, and 5-year estimated SCD risk was calculated (HCM Risk-Kids).

RESULTS

MLVWT Z score was <10 in 598 (58.1%), ≥10 to <20 in 334 (31.1%), and ≥20 in 143 (13.3%). Higher MLVWT Z scores were associated with heart failure symptoms, unexplained syncope, left ventricular outflow tract obstruction, left atrial dilatation, and nonsustained ventricular tachycardia. One hundred twenty-two patients (71.3%) with MLVWT Z score ≥20 had coexisting risk factors for SCD. Over a median follow-up of 4.9 years (interquartile range, 2.3-9.3), 115 (10.7%) had an SCD event. Freedom from SCD event at 5 years for those with MLVWT Z scores <10, ≥10 to <20, and ≥20 was 95.6%, 87.4%, and 86.0, respectively. The estimated SCD risk at 5 years had a nonlinear, inverted U-shaped relationship with MLVWT Z score, peaking at Z score +23. The presence of coexisting risk factors had a summative effect on risk.

CONCLUSIONS

In children with HCM, an inverted U-shaped relationship exists between left ventricular hypertrophy and estimated SCD risk. The presence of additional risk factors has a summative effect on risk. While MLVWT is important for risk stratification, it should not be used either as a binary variable or in isolation to guide implantable cardioverter defibrillator implantation decisions in children with HCM.

Consolidation of the clinical and genetic definition of a SOX4-related neurodevelopmental syndrome

BACKGROUND

A neurodevelopmental syndrome was recently reported in four patients with SOX4 heterozygous missense variants in the high-mobility-group (HMG) DNA-binding domain. The present study aimed to consolidate clinical and genetic knowledge of this syndrome.

METHODS

We newly identified 17 patients with SOX4 variants, predicted variant pathogenicity using in silico tests and in vitro functional assays and analysed the patients' phenotypes.

RESULTS

All variants were novel, distinct and heterozygous. Seven HMG-domain missense and five stop-gain variants were classified as pathogenic or likely pathogenic variant (L/PV) as they precluded SOX4 transcriptional activity in vitro. Five HMG-domain and non-HMG-domain missense variants were classified as of uncertain significance (VUS) due to negative results from functional tests. When known, inheritance was de novo or from a mosaic unaffected or non-mosaic affected parent for patients with L/PV, and from a non-mosaic asymptomatic or affected parent for patients with VUS. All patients had neurodevelopmental, neurological and dysmorphic features, and at least one cardiovascular, ophthalmological, musculoskeletal or other somatic anomaly. Patients with L/PV were overall more affected than patients with VUS. They resembled patients with other neurodevelopmental diseases, including the SOX11-related and Coffin-Siris (CSS) syndromes, but lacked the most specific features of CSS.

CONCLUSION

These findings consolidate evidence of a fairly non-specific neurodevelopmental syndrome due to SOX4 haploinsufficiency in neurogenesis and multiple other developmental processes.

The role of the electrocardiographic phenotype in risk stratification for sudden cardiac death in childhood hypertrophic cardiomyopathy

AIMS

The 12-lead electrocardiogram (ECG) is routinely performed in children with hypertrophic cardiomyopathy (HCM). An ECG risk score has been suggested as a useful tool for risk stratification, but this has not been independently validated. This aim of this study was to describe the ECG phenotype of childhood HCM in a large, international, multi-centre cohort and investigate its role in risk prediction for arrhythmic events.

METHODS AND RESULTS

Data from 356 childhood HCM patients with a mean age of 10.1 years (±4.5) were collected from a retrospective, multi-centre international cohort. Three hundred and forty-seven (97.5%) patients had ECG abnormalities at baseline, most commonly repolarization abnormalities (n = 277, 77.8%); left ventricular hypertrophy (n = 240, 67.7%); abnormal QRS axis (n = 126, 35.4%); or QT prolongation (n = 131, 36.8%). Over a median follow-up of 3.9 years (interquartile range 2.0-7.7), 25 (7%) had an arrhythmic event, with an overall annual event rate of 1.38 (95% CI 0.93-2.04). No ECG variables were associated with 5-year arrhythmic event on univariable or multivariable analysis. The ECG risk score threshold of >5 had modest discriminatory ability [C-index 0.60 (95% CI 0.484-0.715)], with corresponding negative and positive predictive values of 96.7% and 6.7.

CONCLUSION

In a large, international, multi-centre cohort of childhood HCM, ECG abnormalities were common and varied. No ECG characteristic, either in isolation or combined in the previously described ECG risk score, was associated with 5-year sudden cardiac death risk. This suggests that the role of baseline ECG phenotype in improving risk stratification in childhood HCM is limited.

The Leiden Convention coronary coding system: translation from the surgical to the universal view

Aims

The Leiden Convention coronary coding system structures the large variety of coronary anatomical patterns; isolated and in congenital heart disease. It is widely used by surgeons but not by cardiologists as the system uses a surgeons’ cranial view. Since thoracic surgeons and cardiologists work closely together, a coronary coding system practical for both disciplines is mandatory. To this purpose, the ‘surgical’ coronary coding system was adapted to an ‘imaging’ system, extending its applicability to different cardiac imaging techniques.

Methods and results

The physician takes place in the non-facing sinus of the aortic valve, oriented with the back towards the pulmonary valve, looking outward from the sinus. From this position, the right-hand sinus is sinus 1, and the left-hand sinus is sinus 2. Next, a clockwise rotation is adopted starting at sinus 1 and the encountered coronary branches described. Annotation of the normal anatomical pattern is 1R-2LCx, corresponding to the ‘surgical’ coding system. The ‘imaging’ coding system was made applicable for Computed Tomography (CT), Magnetic Resonance Imaging (MRI), echocardiography, and coronary angiography, thus facilitating interdisciplinary use. To assess applicability in daily clinical practice, images from different imaging modalities were annotated by cardiologists and cardiology residents and results scored. The average score upon evaluation was 87.5%, with the highest scores for CT and MRI images (average 90%).

Conclusion

The imaging Leiden Convention is a coronary coding system that unifies the annotation of coronary anatomy for thoracic surgeons, cardiologists, and radiologists. Validation of the coding system shows it can be easily and reliably applied in clinical practice.

Acute and midterm outcomes of the post-approval MELODY Registry: a multicentre registry of transcatheter pulmonary valve implantation

AIMS

The post-approval MELODY Registry aimed to obtain multicentre registry data after transcatheter pulmonary valve implantation (TPVI) with the Melody™ valve (Medtronic plc.) in a large-scale cohort of patients with congenital heart disease (CHD).

METHODS AND RESULTS

Retrospective analysis of multicentre registry data after TPVI with the Melody™ valve. Eight hundred and forty-five patients (mean age: 21.0 ± 11.1 years) underwent TPVI in 42 centres between December 2006 and September 2013 and were followed-up for a median of 5.9 years (range: 0-11.0 years). The composite endpoint of TPVI-related events during follow-up (i.e. death, reoperation, or reintervention >48 h after TPVI) showed an incidence rate of 4.2% per person per year [95% confidence interval (CI) 3.7-4.9]. Transcatheter pulmonary valve implantation infective endocarditis (I.E.) showed an incidence rate of 2.3% per person per year (95% CI 1.9-2.8) and resulted in significant morbidity and in nine deaths. In multivariable Cox proportional hazard models, the invasively measured residual right ventricle (RV)-to-pulmonary artery (PA) pressure gradient (per 5 mmHg) was associated with the risk of the composite endpoint (adjusted hazard ratio: 1.21, 95% CI 1.12-1.30; P < 0.0001) and the risk of TPVI I.E. (adjusted hazard ratio: 1.19, 95% CI 1.07-1.32; P = 0.002). Major procedural complications (death, surgical, or interventional treatment requirement) occurred in 0.5%, 1.2%, and 2.0%, respectively. Acutely, the RV-to-PA pressure gradient and the percentage of patients with pulmonary regurgitation grade >2 improved significantly from 36 [interquartile range (IQR) 24-47] to 12 (IQR 7-17) mmHg and 47 to 1%, respectively (P < 0.001 for each).

CONCLUSION

The post-approval MELODY Registry confirms the efficacy of TPVI with the Melody™ valve in a large-scale cohort of CHD patients. The residual invasively measured RV-to-PA pressure gradient may serve as a target for further improvement in the composite endpoint and TPVI I.E. However, TPVI I.E. remains a significant concern causing significant morbidity and mortality.

Critical Coarctation of the Aorta in Selective Fetal Growth Restriction and the Role of Coronary Stent Implantation

INTRODUCTION

Monochorionic twins are at increased risk of congenital heart defects (CHDs). Up to 26% have a birth weight <1,500 g, a CHD requiring neonatal surgery, therefore, poses particular challenges.

OBJECTIVE

The aim of the study was to describe pregnancy characteristics, perinatal management, and outcome of monochorionic twins diagnosed with critical coarctation of the aorta (CoA).

METHODS

We included monochorionic twins diagnosed with critical CoA (2010-2019) at 2 tertiary referral centers, and we systematically reviewed the literature regarding CoA in monochorionic twins.

RESULTS

Seven neonates were included. All were the smaller twin of pregnancies complicated by selective fetal growth restriction. The median gestational age at birth was 32 weeks (28-34). Birth weight of affected twins ranged as 670-1,800 g. One neonate underwent coarctectomy at the age of 1 month (2,330 g). Six underwent stent implantation, performed between day 8 and 40, followed by definitive coarctectomy between 4 and 9 months in 4. All 7 developed normally, except for 1 child with neurodevelopmental delay. Three co-twins had pulmonary stenosis, of whom 1 required balloon valvuloplasty. The literature review revealed 10 cases of CoA, all in the smaller twin. Six cases detected in the first weeks after birth were treated with prostaglandins alone, by repeated transcatheter angioplasty or by surgical repair, with good outcome in 2 out of 6.

CONCLUSIONS

CoA specifically affects the smaller twin of growth discordant monochorionic twin pairs. Stent implantation is a feasible bridging therapy to surgery in these low birth weight neonates.

Development of a Novel Risk Prediction Model for Sudden Cardiac Death in Childhood Hypertrophic Cardiomyopathy (HCM Risk-Kids)

Importance

Sudden cardiac death (SCD) is the most common mode of death in childhood hypertrophic cardiomyopathy (HCM), but there is no validated algorithm to identify those at highest risk.

Objective

To develop and validate an SCD risk prediction model that provides individualized risk estimates.

Design, Setting, and Participants

A prognostic model was developed from a retrospective, multicenter, longitudinal cohort study of 1024 consecutively evaluated patients aged 16 years or younger with HCM. The study was conducted from January 1, 1970, to December 31, 2017.

Exposures

The model was developed using preselected predictor variables (unexplained syncope, maximal left-ventricular wall thickness, left atrial diameter, left-ventricular outflow tract gradient, and nonsustained ventricular tachycardia) identified from the literature and internally validated using bootstrapping.

Main Outcomes and Measures

A composite outcome of SCD or an equivalent event (aborted cardiac arrest, appropriate implantable cardioverter defibrillator therapy, or sustained ventricular tachycardia associated with hemodynamic compromise).

Results

Of the 1024 patients included in the study, 699 were boys (68.3%); mean (interquartile range [IQR]) age was 11 (7-14) years. Over a median follow-up of 5.3 years (IQR, 2.6-8.3; total patient years, 5984), 89 patients (8.7%) died suddenly or had an equivalent event (annual event rate, 1.49; 95% CI, 1.15-1.92). The pediatric model was developed using preselected variables to predict the risk of SCD. The model's ability to predict risk at 5 years was validated; the C statistic was 0.69 (95% CI, 0.66-0.72), and the calibration slope was 0.98 (95% CI, 0.59-1.38). For every 10 implantable cardioverter defibrillators implanted in patients with 6% or more of a 5-year SCD risk, 1 patient may potentially be saved from SCD at 5 years.

Conclusions and Relevance

This new, validated risk stratification model for SCD in childhood HCM may provide individualized estimates of risk at 5 years using readily obtained clinical risk factors. External validation studies are required to demonstrate the accuracy of this model's predictions in diverse patient populations.

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.

Fifteen years' experience with the use of artificial chords for valve reconstruction in children

OBJECTIVES

To retrospectively review our experience with artificial chords in mitral and tricuspid reconstructive surgery in children.

METHODS

All consecutive paediatric (<18 years) patients who underwent mitral or tricuspid valve reconstruction with the use of artificial chords in our centre in the past 15 years were retrospectively analysed.

RESULTS

Thirty-nine patients (age 3 days to 17 years) underwent reconstruction of the mitral (n = 27) or tricuspid (n = 12) valve using artificial chords. Mean number of chords was 3.5 ± 1.7. In 26 of 27 mitral valve patients, chords were placed on the anterior leaflet, in one on the posterior leaflet. In 10 of the 12 tricupid valve, patients chords were placed on the anterior leaflet and in 2 on the septal leaflet. All mitral patients underwent annuloplasty (10 bilateral Wooler-Kay and 17 rigid ring annuloplasty). Ten of the 12 tricuspid patients underwent annuloplasty (1 rigid ring and 9 commissural plication). Follow-up was after 8.7 ± 5.5 years. There was no early or late mortality. The actuarial freedom from reoperation rates at 1, 5 and 10 years were 95%, 91% and 81%, respectively. No reoperations occurred in the tricuspid group. In the mitral group, there were 2 early failures and 3 late reoperations due to mitral stenosis. Restricted leaflet motion probably caused by the artificial chords was seen in only 1 patient.

CONCLUSIONS

Our data show that long-term durability of mitral and tricuspid valve reconstruction using artificial chords in children is good. Despite patient growth, restricted leaflet motion by the artificial chords does not seem to form a major problem.

Surgical Correction of Supravalvar Aortic Stenosis: 52 Years' Experience

OBJECTIVES

Supravalvar aortic stenosis (SVAS) is a rare congenital anomaly. The "single-patch technique," "'two sinus augmentation with an inverted Y-patch" (both nonsymmetrical corrections), "three-patch technique," and the "slide aortoplasty" (both symmetrical corrections) are the techniques implemented by the majority of surgeons for the correction of SVAS. In the few studies that compared these techniques, no technique was shown to be superior over another. The aim of the present study is to review the 52-year experience with the surgical correction of SVAS in two of four congenital cardiothoracic surgical centers in the Netherlands.

METHODS

We retrospectively reviewed all patient files of those who underwent an operation to correct their SVAS, between 1962 and 2014 in our centers. Patients were divided according to their operating technique. These groups were compared using the end points freedom from reoperation and mortality.

RESULTS

A total of 49 patients were included, 23 (46.9%) patients in the nonsymmetrical group and 26 (53.1%) patients in the symmetrical group. Survival after 20 years in the nonsymmetrical group was 80% (standard error [SE]: 0.091) and in the symmetrical group was 85% (SE: 0.085; P = .163). Freedom from reoperation after 20 years in the nonsymmetrical group was 88% (SE: 0.079) and in the symmetrical group was 71% (SE: 0.107; P = 0.313).

CONCLUSION

In this patient group, there is no significant difference in survival and freedom from reoperation between the different surgical techniques for SVAS repair. Compared to the survival in the general population, the survival of SVAS patients is remarkably low. Apparently, SVAS is not a benign disease and probably patients should be followed more closely for the rest of their lives.

Pulmonary Valve Morphology in Patients with Bicuspid Aortic Valves

The aortic and pulmonary valve share a common developmental origin from the embryonic arterial trunk. Bicuspid aortic valve is the most common congenital anomaly and can occur isolated as well as in association with other congenital heart disease (CHD). Data on pulmonary valve morphology in these cases are scarce. In this study, we aimed to determine pulmonary valve morphology in hearts with BAV associated with CHD. In 83 post-mortem heart specimens with BAV and associated CHD, pulmonary valve morphology was studied and related to BAV morphology. In 14/83 (17%) hearts, the pulmonary valve was affected, bicuspid in 8/83 (10%), dome-shaped in 3/83 (4%) and atretic in 3/83 (4%). In specimens with a bicuspid pulmonary valve, 5/8 (63%) had a strictly bicuspid aortic valve (without raphe), 2/3 hearts (67%) with dome-shaped pulmonary valves and 2/3 hearts (67%) with atretic pulmonary valves had BAV without raphe. Six out of eight (75%) specimens with a bicuspid pulmonary valve had a perimembranous ventricular septal defect (VSD). 4/8 (50%) specimens with a bicuspid pulmonary valve were associated with chromosomal abnormalities: 3 (38%) had trisomy 18 and 1 (13%) had trisomy 13. In BAV with associated CHD, abnormal pulmonary valve morphology was observed in 17% of the hearts. The majority of hearts with abnormal pulmonary valve morphology had a Type B bicuspid aortic valve (without raphe). Bilateral semilunar valvular disease is associated with Type B BAVs and in many cases related to chromosomal abnormalities. As this study was performed in post-mortem specimens with high frequency of associated CHD, caution is warranted with application of these results to the general BAV population.

A Dutch MYH7 founder mutation, p.(Asn1918Lys), is associated with early onset cardiomyopathy and congenital heart defects

Background

Mutations in the myosin heavy chain 7 (MYH7) gene commonly cause cardiomyopathy but are less frequently associated with congenital heart defects.

Methods

In this study, we describe a mutation in the MYH7 gene, c. 5754C > G; p. (Asn1918Lys), present in 15 probands and 65 family members.

Results

Of the 80 carriers (age range 0–88 years), 46 (57.5%) had cardiomyopathy (mainly dilated cardiomyopathy (DCM)) and seven (8.8%) had a congenital heart defect. Childhood onset of cardiomyopathy was present in almost 10% of carriers. However, in only a slight majority (53.7%) was the left ventricular ejection fraction reduced and almost no arrhythmias or conduction disorders were noted. Moreover, only one carrier required heart transplantation and nine (11.3%) an implantable cardioverter defibrillator. In addition, the standardised mortality ratio for MYH7 carriers was not significantly increased. Whole exome sequencing in several cases with paediatric onset of DCM and one with isolated congenital heart defects did not reveal additional known disease-causing variants. Haplotype analysis suggests that the MYH7 variant is a founder mutation, and is therefore the first Dutch founder mutation identified in the MYH7 gene. The mutation appears to have originated in the western region of the province of South Holland between 500 and 900 years ago.

Conclusion

Clinically, the p. (Asn1918Lys) mutation is associated with congenital heart defects and/or cardiomyopathy at young age but with a relatively benign course.

Electronic supplementary material

The online version of this article (10.1007/s12471-017-1037-5) contains supplementary material, which is available to authorized users.

Coronary anatomy in children with bicuspid aortic valves and associated congenital heart disease

Objective

In patients with bicuspid aortic valve (BAV), coronary anatomy is variable. High take-off coronary arteries have been described, but data are scarce, especially when associated with complex congenital heart disease (CHD). The purpose of this study was to describe coronary patterns in these patients.

Methods

In 84 postmortem heart specimens with BAV and associated CHD, position and height of the coronary ostia were studied and related to BAV morphology.

Results

High take-off right (RCA) and left coronary arteries (LCA) were observed in 23% and 37% of hearts, respectively, most frequently in hearts with hypoplastic left ventricle (HLV) and outflow tract anomalies. In HLV, high take-off was observed in 18/40 (45%) more frequently of LCA (n=14) than RCA (n=6). In hearts with aortic hypoplasia, 8/13 (62%) had high take-off LCA and 6/13 (46%) high take-off RCA. High take-off was seen 19 times in 22 specimens with perimembranous ventricular septal defect (RCA 8, LCA 11). High take-off was associated with type 1A BAV (raphe between right and left coronary leaflets), more outspoken for the RCA. Separate ostia of left anterior descending coronary artery and left circumflex coronary artery were seen in four hearts (5%), not related to specific BAV morphology.

Conclusion

High take-off coronary arteries, especially the LCA, occur more frequently in BAV with associated CHD than reported in normal hearts and isolated BAV. Outflow tract defects and HLV are associated with type 1A BAV and high take-off coronary arteries. Although it is unclear whether these findings in infants with detrimental outcome can be related to surviving adults, clinical awareness of variations in coronary anatomy is warranted.

Dlx1 and Rgs5 in the ductus arteriosus: vessel-specific genes identified by transcriptional profiling of laser-capture microdissected endothelial and smooth muscle cells

Closure of the ductus arteriosus (DA) is a crucial step in the transition from fetal to postnatal life. Patent DA is one of the most common cardiovascular anomalies in children with significant clinical consequences especially in premature infants. We aimed to identify genes that specify the DA in the fetus and differentiate it from the aorta. Comparative microarray analysis of laser-captured microdissected endothelial (ECs) and vascular smooth muscle cells (SMCs) from the DA and aorta of fetal rats (embryonic day 18 and 21) identified vessel-specific transcriptional profiles. We found a strong age-dependency of gene expression. Among the genes that were upregulated in the DA the regulator of the G-protein coupled receptor 5 (Rgs5) and the transcription factor distal-less homeobox 1 (Dlx1) exhibited the highest and most significant level of differential expression. The aorta showed a significant preferential expression of the Purkinje cell protein 4 (Pcp4) gene. The results of the microarray analysis were validated by real-time quantitative PCR and immunohistochemistry. Our study confirms vessel-specific transcriptional profiles in ECs and SMCs of rat DA and aorta. Rgs5 and Dlx1 represent novel molecular targets for the regulation of DA maturation and closure.

Repeated courses of ibuprofen are effective in closure of a patent ductus arteriosus

Patent ductus arteriosus (PDA) is a frequent complication in preterm infants. Ibuprofen and indomethacin (both COX inhibitors) are used for pharmacological closure of PDA. In most centers, a failed second course of COX inhibitors is followed by surgical closure. Our aim was to estimate the closure rate of clinically significant PDA after second and third courses of ibuprofen and record possible side effects. A study population, consisting of 164 preterm infants (<32 weeks' gestational age) with PDA admitted at our tertiary care center between November 2005 and September 2011, was retrospectively analyzed. Primary outcome was the closure rate after repeated courses of ibuprofen. The closure rate was similar after the first (109/164), second (24/43), and third (6/11) course of ibuprofen (X(2) = 2.1, p = 0.350). Late start of the first course of ibuprofen was a predictive factor for increased need of a second course (X(2) = 4.4, p = 0.036). No additional side effects of multiple courses of ibuprofen were detected. In conclusion, repeated courses of ibuprofen are an effective and safe alternative for surgical closure and should be considered after failure of the first course of ibuprofen.

Differential temporal and spatial progerin expression during closure of the ductus arteriosus in neonates

Closure of the ductus arteriosus (DA) at birth is essential for the transition from fetal to postnatal life. Before birth the DA bypasses the uninflated lungs by shunting blood from the pulmonary trunk into the systemic circulation. The molecular mechanism underlying DA closure and degeneration has not been fully elucidated, but is associated with apoptosis and cytolytic necrosis in the inner media and intima. We detected features of histology during DA degeneration that are comparable to Hutchinson Gilford Progeria syndrome and ageing. Immunohistochemistry on human fetal and neonatal DA, and aorta showed that lamin A/C was expressed in all layers of the vessel wall. As a novel finding we report that progerin, a splicing variant of lamin A/C was expressed almost selectively in the normal closing neonatal DA, from which we hypothesized that progerin is involved in DA closure. Progerin was detected in 16.2%±7.2 cells of the DA. Progerin-expressing cells were predominantly located in intima and inner media where cytolytic necrosis accompanied by apoptosis will develop. Concomitantly we found loss of α-smooth muscle actin as well as reduced lamin A/C expression compared to the fetal and non-closing DA. In cells of the adjacent aorta, that remains patent, progerin expression was only sporadically detected in 2.5%±1.5 of the cells. Data were substantiated by the detection of mRNA of progerin in the neonatal DA but not in the aorta, by PCR and sequencing analysis. The fetal DA and the non-closing persistent DA did not present with progerin expressing cells. Our analysis revealed that the spatiotemporal expression of lamin A/C and progerin in the neonatal DA was mutually exclusive. We suggest that activation of LMNA alternative splicing is involved in vascular remodeling in the circulatory system during normal neonatal DA closure.

Accessory atrioventricular myocardial pathways in mouse heart development: substrate for supraventricular tachycardias

Atrioventricular reentry tachycardia (AVRT) requiring an accessory atrioventricular pathway (AP) is the most common type of arrhythmia in the perinatal period. The etiology of these arrhythmias is not fully understood as well as their capability to dissipate spontaneously in the first year of life. Temporary presence of APs during annulus fibrosus development might cause this specific type of arrhythmias. To study the presence of APs, electrophysiological recordings of ventricular activation patterns and immunohistochemical analyses with antibodies specifically against atrial myosin light chain 2 (MLC-2a), Periostin, Nkx2.5, and Connexin-43 were performed in embryonic mouse hearts ranging from 11.5 to 18.5 days post-conception (dpc). The electrophysiological recordings revealed the presence of functional APs in early (13.5-15.5 dpc) and late (16.5-18.5 dpc) postseptated stages of mouse heart development. These APs stained positive for MLC-2a and Nkx2.5 and negative for Periostin and Connexin-43. Longitudinal analyses showed that APs gradually decreased in number (p = 0.003) and size (p = 0.035) at subsequent developmental stages (13.5-18.5 dpc). Expression of periostin was observed in the developing annulus fibrosus, adjacent to APs and other locations where formation of fibrous tissue is essential. We conclude that functional APs are present during normal mouse heart development. These APs can serve as transient substrate for AVRTs in the perinatal period of development.

Insights into the pathogenesis and genetic background of patency of the ductus arteriosus

The unique differentiation program of the ductus arteriosus (DA) is essential for its specific task during fetal life and for the adapting circulation after birth. Phenotypic changes occur in the DA during the normal maturation and definitive closure. Morphological abnormalities of the vessel wall characterize the persistent DA (PDA) in older children. Here, we give an overview of the animal models of DA regulation and remodeling. Genetic research has identified the cause of syndromic forms of PDA, such as the TFAP2B mutations in Char syndrome. Genes that interfere with the remodeling of vascular smooth muscle cells (VSMCs) of the ductal media are affected in virtually all of these anomalies. Therefore, the pivotal regulatory role of VSMCs is emphasized. A better understanding of the genetic background of this developmental process may help develop new strategies to manipulate the DA in premature infants, neonates with duct-dependent anomalies, and patients with syndromic and non-syndromic PDA.

Fetal cardiac output in monochorionic twins

OBJECTIVES

To compare fetal cardiac output (CO) in donor and recipient twins of twin-twin transfusion syndrome (TTTS) pregnancies after laser therapy with that of monochorionic twins without TTTS and normal singletons.

METHODS

In a longitudinal, prospective study, we sonographically assessed fetal CO in donors (n = 10) and recipients (n = 10) with TTTS after fetoscopic laser therapy, in monochorionic twins without TTTS (n = 20) and in normal singleton pregnancies (n = 20). The fetal CO of TTTS twins was determined 1 day and 1 week after laser treatment, and from then on every 2-4 weeks until birth. Twins without TTTS were examined biweekly until birth. Singletons were examined twice, with an 8-week interval, at different gestational ages between 17 and 35 weeks.

RESULTS

Absolute CO increased exponentially with advancing gestational age (P < 0.0001), and was significantly related to fetal weight in all groups (P < 0.0001). The median CO/kg in donors after laser therapy, recipients after laser therapy and non-TTTS monochorionic twins was significantly higher than that in singletons (all P < 0.001). Median CO/kg in donors after laser therapy, recipients after laser therapy, and non-TTTS monochorionic twins was not significantly different between groups.

CONCLUSIONS

Monochorionic twins with TTTS have higher CO after laser therapy than normal singletons.

Congenital heart disease in twin-to-twin transfusion syndrome treated with fetoscopic laser surgery

OBJECTIVE

To determine the incidence of congenital heart disease (CHD) and right ventricular outflow tract obstruction (RVOTO) in twin-to-twin transfusion syndrome (TTTS) treated with fetoscopic laser surgery and evaluate the role of increased afterload by determining the difference in blood pressure and endothelin-1 at birth between donor and recipient twins.

DESIGN

Prospective study.

SETTING

Tertiary medical center, serving as the national referral center for fetoscopic laser surgery for TTTS in The Netherlands.

PATIENTS

All consecutive cases of monochorionic twins with TTTS treated with laser (n = 46 twin pairs) and monochorionic twins without TTTS (n = 55 twin pairs) delivered at our center between June 2002 and June 2005 were included in the study.

INTERVENTIONS

Echocardiography was performed within 1 week after delivery. At birth, blood pressure was measured in all survivors and endothelin-1 was determined in umbilical cord blood. Data on RVOTO in TTTS treated with laser surgery at our center but delivered elsewhere were reviewed retrospectively from medical records.

RESULTS

The incidence of CHD in the TTTS group and non-TTTS group was 5.4% (4/74) and 2.3% (2/87) (P = .42), respectively. RVOTO was diagnosed in 1 recipient twin delivered at our center and 2 recipient twins delivered elsewhere. The incidence of RVOTO in recipients was 4% (3/75). Mean systolic blood pressure at birth was similar in donor and recipient twins, respectively, 53 mm Hg vs. 56 mm Hg (P = .42). Mean endothelin-1 level at birth was also similar between donors and recipients, respectively, 14.3 ng/L and 13.2 ng/L (P = .64).

CONCLUSION

The incidence of CHD in TTTS treated with fetoscopic laser surgery is higher than in the general population (5.4% vs. 0.5%). We found no difference in afterload parameters between donors and recipients after laser treatment.

[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.

Early complications of stenting in patients with congenital heart disease: a multicentre study

AIMS

Stenting has become an established interventional cardiology procedure for congenital heart disease. Although most stent procedures are completed successfully, complications may occur. This multicentre study evaluated early complications after stenting in patients with congenital heart disease, including potential risk factors.

METHODS AND RESULTS

In this combined Dutch-Belgian retrospective study, 309 consecutive patients had undergone 366 catheterizations and received 464 stents in 13 different anatomical positions (418 sites). Seventy-two stenting-related complications (19%) occurred, of which 24 (5.7%) were major. Seven procedure-related deaths were documented (2.3%). Stent malpositioning and embolization were most common (7.7%). The use of non-premounted stents tended to be associated with higher complication rates. Centre inexperience with stenting and stenting of native vs. post-surgical stenosis tended to be associated with increased major complication rates.

CONCLUSION

After stenting, complications are common for congenital heart disease. The vast diversity of stenotic sites combined with relatively small patient populations makes these procedures sensitive to complications. Combining operator experience may reduce the risks of stenting in congenital heart disease. The availability of premounted stents for greater vessel diameters will likely reduce incidences of stent migration and embolization.

Persistent ductus arteriosus in the Brown-Norway inbred rat strain

Persistent ductus arteriosus (PDA) is a common cardiovascular anomaly in children caused by the pathologic persistence of the left sixth pharyngeal arch artery. The inbred Brown-Norway (BN) rat presents with increased vascular fragility due to an aortic elastin deficit resulting from decreased elastin synthesis. The strikingly high prevalence of PDA in BN rats in a pilot study led us to investigate this vascular anomaly in 12 adolescent BN rats. In all BN rats, a PDA was observed macroscopically, whereas a ligamentum arteriosum was found in adult controls. The macroscopic appearance of the PDA was tubular (n = 2), stenotic (n = 8), or diverticular (n = 2). The PDA had the structure of a muscular artery with intimal thickening. In the normal closing ductus of the neonatal controls, the media consisted of layers of smooth muscle cells (SMCs) intermingled with layers of elastin. The intima was thin and poor in elastin. By contrast, the media of PDA in BN rats elastin lamellae were absent and the intima contained many elastic fibers. The abnormal distribution of elastin in the PDA of BN rats suggests that impaired elastin metabolism is related to the persistence of the ductus and implicates a genetically determined factor that may link the PDA with aortic fragility.

Cystatin C, kidney function and cardiovascular disease

Cystatin C, an endogenous low-molecular-weight marker of glomerular filtration rate, has recently been shown to be associated with future cardiovascular disease in healthy elderly populations and patients with documented atherosclerosis in a dose-dependent manner that possibly reflects a very early stage of chronic renal dysfunction. At the same time, local cystatin C deficiency has been demonstrated in atherosclerotic and aneurismal lesions, suggesting a protective role of cystatin C in the vessel wall, possibly in concert with TGF-beta1. Although cystatin C is not an acute phase reactant, large epidemiological studies have documented a highly significant association between serum cystatin C and mildly increased C-reactive protein (CRP) levels, the hallmark of the chronic inflammatory state associated with atherosclerosis and chronic renal failure. Since cystatin C is produced by all nucleated cells, it is unlikely that local variations in cystatin C synthesis in diseased arteries--rather than global cystatin C production and renal elimination--should determine its serum concentration. Consequently, the present review proposes microinflammation as the unifying concept for both lines of evidence.

Stenting of the vertical vein in obstructed total anomalous pulmonary venous return as rescue procedure in a neonate

A newborn girl with progressive respiratory distress and cyanosis was found to have severely obstructed supracardiac total pulmonary venous return (TAPVR). Stenting of the stenosis provided immediate and effective relief of the obstruction until corrective surgery was performed. Catheter intervention should be considered in high-risk infants with obstructed supracardiac TAPVR as part of the strategy for preoperative cardiovascular stabilization.

Low-energy radiofrequency catheter ablation as therapy for supraventricular tachycardia in a premature neonate

A premature neonate with hydrops was born at 32 weeks of gestation after successful direct fetal amiodarone therapy via cordocentesis for incessant supraventricular tachycardia. After birth the tachycardia could not be controlled despite high doses of amiodarone and flecainide and the patient developed severe respiratory and circulatory failure. After 3 weeks, weighing 2 kg, he underwent successful and uncomplicated catheter ablation of a left free-wall accessory pathway using low-energy radiofrequency.

CONCLUSION

radiofrequency catheter ablation is rarely used in neonates, but when used with caution may provide the optimal treatment.

[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.

Intraoperative stenting of pulmonary arteries

OBJECTIVE

The surgical treatment of pulmonary artery stenoses in small children with complex cardiac lesions can be technically difficult. A hybrid-approach combining corrective surgery and intraoperative stent placement may be complementary in these patients.

METHODS

Descriptive study in 11 small children (age: one week to 12 years, median of 12 months, weight: 2.5-20 kg) after previous cardiac surgery. Intraoperative stenting of pulmonary arteries was performed involving paediatric cardiologist and cardiac surgeon. Stenting was combined with repair of pulmonary atresia (n=2), right ventricular outflow and pulmonary artery reconstruction (n=3), unifocalisation of pulmonary arteries (n=1), revision of distal anastomosis of RV-PA-conduit after truncus repair (n=1), revision of distal anastomosis of RV-PA-conduit after AVSD/Fallot repair (n=1), aortic arch patch reconstruction after anatomical correction for transposition of the great arteries (n=1), bidirectional cavopulmonary anastomosis after Norwood I operation for hypoplastic left heart syndrome, (n=1) retrieval of a dislodged stent from the left pulmonary artery (n=1). In seven patients stenting was planned electively while in four patients it took place on an emergency base.

RESULTS

No complications occurred during stent implantation. One patient died three weeks postoperatively from diffuse bleeding due to a coagulation disorder. Ten patients left hospital after the surgical intervention with concomitant stent implantation. Stent re-dilatation was necessary in 4 patients 2-24 months postoperatively. After a median follow-up of 15 months ranging from 3 weeks to 7.5 years all stents were patent as diagnosed by angiography in 6 patients and by colour-Doppler in all other patients. One year after stent placement one stent was removed and another surgically opened during re-operation for conduit replacement in the smallest patient from this series. There was one late death during operative right ventricular outflow-tract reconstruction after initial stent placement.

CONCLUSIONS

With intraoperative stent placement surgically difficult patch augmentation of small and fragile pulmonary vessels during repair of complex cardiac lesions can be avoided. Stents recruit pulmonary vessels and keep them open and amenable to future percutaneous or surgical interventions.

Incidence and time course of intimal plaque formation in the right coronary artery after radiofrequency current application detected by intracoronary ultrasound

BACKGROUND

Despite the current clinical use of radiofrequency (RF) catheter ablation in infants and children, the late effects of RF current application at immature myocardium remain unclear. The purpose of this study was to investigate incidence and time course of coronary lesions after RF current application at developing myocardium in an animal model.

RESULTS

In 10 pigs, 6 weeks of age (13+/-2 kg), RF current (500 kHz) was delivered by temperature guidance (75 degrees C) using a steerable electrode catheter (4 mm tip electrode) over 30-second periods. RF lesions were created at the lateral right atrial wall at the tricuspid valve annulus and the lateral left atrial and ventricular wall at the mitral valve annulus. Subsequent coronary angiography and intracoronary ultrasound (ICUS) of the right coronary artery (RCA) and the left circumflex artery (CX) were performed 3, 6, 9 and 12 months after RF current application. Quantitative coronary angiography did not exhibit any significant stenosis of the vessels during the study period. Intimal lesions of the RCA were documented for the first time at the 6-month study in 3 animals by ICUS (mean plaque area 2.2+/-0.2 mm(2), mean area stenosis 30.4+/-4.0%). There was no significant change in lesion length, area stenosis and plaque area at the 9- and 12-month studies. All 3 coronary artery lesions were confirmed in close proximity to myocardial RF lesions by histological examination 12 months after RF delivery. No intimal plaque formation of the CX was observed.

CONCLUSIONS

Affection of the RCA as a late sequel after RF current application at the lateral right atrial wall occurred in 3 out of 8 long-term surviving pigs. Three to six months seem to be the time frame for the development of intimal lesions after RF delivery. In this experimental setting, angiography failed to detect these intimal changes. The potential risk of coronary affection may be important for catheter ablation procedures at the right atrial myocardium in infants and small children.

Resynchronization Therapy After Congenital Heart Surgery to Improve Left Ventricular Function

This report describes the mid-term beneficial hemodynamic effect of biventricular pacing in an infant with congestive heart failure after congenital heart surgery, due to resynchronization of the left and right ventricle, optimization of the AV delay, and (partial) correction of the LV dyssynchrony.

[Arrhythmogenic right ventricular dysplasia/cardiomyopathy - diagnosis in childhood]

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is a rare, but important cause for sudden death in adolescents and young adults. Part of the patients affected show the pattern of autosomal-dominant inheritance. Two pediatric patients with ARVD/C are presented who may reflect the spectrum of clinical presentation of ARVD/C in childhood resulting in difficulties or even delay to establish the correct diagnosis. One patient with a sporadic form of ARVD/C presented with a syncope and spontaneous as well as inducible ventricular tachycardia. On the ECG, an epsilon wave could be identified. An automatic cardioverter defibrillator was implanted. The second patient had a familiar form of ARVD/C with no symptoms. There was a history of frequent sudden deaths in this family. Biopsies of the right ventricular myocardium showed fibrosis with deposition of fatty tissue. There was clear evidence of ARVD/C in the necropsy of the patient's aunt. Therapy with propanolol was started in this patient.

Abbreviated combined anatomical/electrophysiological approach for catheter ablation of atrioventricular nodal reentrant tachycardia in children

Atrioventricular nodal reentrant tachycardia was proven during electrophysiologic study in 41 children, aged from 3.7 to 16 years, who were referred for catheter ablation of symptomatic supraventricular tachycardia. Using an abbreviated combined anatomical and electrogram-guided approach for selective ablation of the slow pathway, a steerable ablation catheter was placed at the inferior region of the vestibule of the tricuspid valve close to the orifice of the coronary sinus, with the intention of recording a multicomponent local atrial electrogramm during sinus rhythm. If application of radiofrequency current of 500 kHz at 70 degrees C at this site did not result in a slowly accelerated junctional rhythm, at a rate of less than 120 beats per minute, the catheter was stepwise advanced up to a position midway towards the apex of the triangle of Koch for additional applications of energy. Ablation was achieved in 35 of the patients. In 6 patients, the slow pathway was modulated such that the tachycardia could no longer be induced. The number of applications of energy ranged from 1 to 19, with a median of 6 applications. The mean period of fluoroscopy was reduced to 15.6 (4.3 to 39.8) minutes, while the overall duration of the catheterization procedures ranged from 88 to 280 (mean 173.2) minutes. In none of the patients did we observe permanent high grade atrioventricular block. During follow-up over a mean of 4.1 years, two patients had recurrence of tachycardia, corresponding to a 95% rate of success in the midterm. We conclude that selective radiofrequency ablation of the slow pathway using the abbreviated anatomical and electrophysiological approach is a safe and curative therapeutic approach in children with atrioventricular nodal reentrant tachycardia. Periods required for fluoroscopy can be significantly reduced, and mid-term results are excellent.

Coronary artery stenosis after radiofrequency catheter ablation of accessory atrioventricular pathways in children with Ebstein's malformation

BACKGROUND

Complications concerning the coronary arteries that are directly related to radiofrequency catheter ablation procedures have not been reported in children. Coronary artery lesions, however, have been demonstrated after the endocardial application of radiofrequency current in young animals.

METHODS AND RESULTS

Two boys with Ebstein's anomaly of the tricuspid valve developed clinically asymptomatic coronary artery stenosis after radiofrequency catheter ablation of right-sided accessory atrioventricular pathways with standard catheter technology.

CONCLUSIONS

The complication of coronary artery stenosis demonstrates a substantial risk after right atrial free wall radiofrequency current application in children. The risk of late coronary alterations should be considered when the use of catheter ablation procedures to young patients is proposed.

[Atrioventricular nodal reentry tachycardia in children: curative treatment by high frequency catheter ablation]

BACKGROUND

Atrioventricular nodal reentrant tachycardia (AVNRT) is one of the most common forms of supraventricular tachycardia in the pediatric population.

PATIENTS AND METHODS

41 children with a mean age of 9.6 (3.7-16) years with recurrent atrioventricular nodal reentrant tachycardia (AVNRT) refractory to medical treatment (n = 38) and recurrent syncope (n = 3) underwent electrophysiologic (EP) study. In all patients dual AV-nodal physiology could be demonstrated during EP study and typical form of AVNRT (mean heart rate 220/min) could be induced by programmed atrial stimulation. A steerable 7 F ablation catheter was placed at the inferoparaseptal region of the tricuspid valve annulus close to the orifice of the coronary sinus with the intention to record a late fractionated local atrial electrogram during sinus rhythm. Starting at this point radiofrequency current (500 kHz) with a target temperature of 70 degrees C was delivered with the intention to ablate the slow pathway. If a slowly accelerated junctional rhythm (< 120/min) occurred during energy discharge, programmed atrial stimulation was repeated. Otherwise radiofrequency current was delivered step by step up to a septal position next to the tricuspid valve annulus. Slow pathway ablation was defined as lack of evidence of dual AV nodal pathways during repeated atrial stimulation. Slow pathway modulation was defined as maximal one atrial echoimpulse after ablation.

RESULTS

The number of energy applications ranged from 1-19 (median 6). In 35/41 patients slow pathway ablation could be achieved; in six patients the slow pathway was modulated. In none of the patients permanent high grade AV block was observed. During follow-up (mean 4.1 years) two patients had a recurrent episode of AVNRT after slow pathway modulation. All other patients are still free of AVNRT without medical treatment.

CONCLUSION

Selective radiofrequency current ablation/modulation of the slow pathway is a safe and curative treatment of AVNRT in young patients.

Effects of intracardiac radiofrequency current application on coronary artery vessels in young pigs

INTRODUCTION

Radiofrequency current is widely used in children to ablate accessory AV pathways. Previous data in a pig model demonstrated coronary artery obstruction adjacent to radiofrequency current lesions 48 hours and 6 months after energy delivery. In the present study, the long-term effects (>6 months) of radiofrequency current application on coronary artery vessels in young pigs are assessed.

METHODS AND RESULTS

Radiofrequency current (500 kHz) was delivered over 30 seconds in ten piglets (mean body weight 12.8 kg) using a steerable 6-French catheter with a 4-mm thermistor tip electrode (target temperature 75 degrees C). Lesions were created under fluoroscopic and electrocardiographic guidance at the lateral right atrial (RA) wall above the tricuspid valve orifice, and at the lateral left atrial and left ventricular wall adjacent to the mitral valve orifice. Selective coronary angiography and intravascular ultrasound (IVUS) studies were performed 3, 6, 9, and 12 months after energy application. After 12 months, the lesions were studied pathohistologically. All lesions consisted of compact fibrous tissue. RA lesions extended to the adjacent right coronary artery and led to coronary artery involvement with increased fibrous tissue in the adventitia and media and intimal thickening in three animals. Coronary arterial narrowing was documented by IVUS during follow-up in all three cases 9 months after energy application. Angiography failed to demonstrate coronary pathology in any of the three animals.

CONCLUSION

The risk of late coronary artery lesions must be considered when catheter ablation at the RA wall is planned in children with free-wall accessory AV pathways.

Supraventricular tachycardia in infants, children and adolescents: diagnosis, and pharmacological and interventional therapy

Supraventricular tachycardia is the most frequent form of symptomatic tachydysrhythmia in children. Neonates and infants with paroxysmal supraventricular tachycardias generally present with signs of acute congestive heart failure. In school-aged children and adolescents, palpitations are the leading symptom. Chronic-permanent tachycardia results in a secondary form of dilated cardiomyopathy. Therapy for episodes of tachycardia depends on the individual situation. In severe haemodynamic compromise, or if ventricular tachycardia is suspected, tachycardia should immediately be terminated by external cardioversion during deep sedation. Vagal manoeuvres are effective in patients with atrioventricular reentrant tachycardias. Adenosine is the drug of first choice in any age group for tachycardias involving the atrioventricular node; its advantages include short half-life and minimal or absent negative inotropic effects. Adenosine may also be used in patients with wide QRS complex tachycardia. Intravenous verapamil is contraindicated in neonates and infants because of the high risk of electromechanical dissociation. In older children (>5 years) and adolescents, verapamil may be administered with the same restrictions as in adult patients (wide QRS complex tachycardia, significant haemodynamic compromise). Spontaneous cessation of tachycardia can be expected in most neonates and infants during the first year of life. Prophylactic pharmacological treatment in this age group is advisable because recognition of tachycardia is often delayed until the occurrence of symptoms. Withdrawal of drug treatment should be attempted around the end of the first year. However, in older children, spontaneous cessation of tachycardia is rare. Prophylactic drug therapy is performed on an empirical basis. Digoxin may be administered in all forms of supraventricular tachycardia in which the atrioventricular node is involved, except in patients with pre-excitation syndrome aged >1 year. In patients with atrioventricular reentrant tachycardia, class IC drugs such as flecainide and propafenone are effective. Sotalol is also effective in atrioventricular reentrant tachycardia, as well as in primary atrial tachycardia. Although amiodarone has the highest antiarrhythmic potential, it should be used with caution because of its high rate of adverse effects. In school-aged children and adolescents, radiofrequency catheter ablation of the anatomical substrate is an attractive alternative to drug therapy, with a rate of permanent cessation of the tachycardia of up to 90%. Despite the clear advantages of this procedure, it should be performed only with unquestionable indication; the long term morphological and electrophysiological sequelae on the growing atrial and ventricular myocardium are still unknown.