BackgroundAtrial septal defects (ASD) are associated with an increased incidence of atrial arrhythmias, but their electrophysiological consequences are poorly defined. We hypothesised that conduction and repolarisation would be preferentially altered in the right atrium of ASD patients.ObjectiveTo quantify atrial conduction and repolarisation in ASD patients and determine the impact of structural remodelling on restitution properties.MethodsPatients with an ASD (n = 22) underwent bi-atrial electroanatomic mapping and quantification of effective refractory periods, longitudinal and transverse local conduction. The control group comprised 24 patients without an ASD undergoing ablation for paroxysmal AF.ResultsBipolar voltage was significantly lower in ASD patients (right atrium: 1.53 ± 0.46 mV versus 1.98 ± 0.59 mV, P = 0.017; left atrium: 1.71 ± 0.36 mV versus 2.06 ± 0.63 mV, P = 0.039). There was no significant difference in global conduction velocity in either atrium between ASD and control patients. Effective refractory periods at 600 ms were not significantly different between patient groups (right atrium: 247 ± 34.7 ms versus 224 ± 36.5 ms, P = 0.071; left atrium: 244 ± 23.9 ms versus 232 ± 40.4 ms, P = 0.29). However, both conduction and repolarisation demonstrated greater rate adaptation in ASD patients in both atria.ConclusionRight atrial remodelling, characterised by atrial dilatation and increased low voltage, is present in ASD patients. During fixed rate pacing, conduction and repolarisation properties are similar between ASD and AF patients. However, the restitution properties of both conduction and repolarisation are more pronounced in ASD than AF patients.

BACKGROUND:Percutaneous pulmonary valve implantation (PPVI) is an alternative to surgery for dysfunctional right ventricular outflow tracts (RVOTs). The VenusP-valve is a self-expanding transcatheter valve, available in diameters from 24 to 36 mm, and is designed for use in the larger RVOTs. AIMS:A retrospective review to evaluate the medium to long-term results of the VenusP-valve, focusing on patient outcomes and durability of the valve. METHODS:Between October 2013 and September 2018, 58 patients with severe pulmonary regurgitation (PR) underwent attempted PPVI with the VenusP-valve at Evelina London Children's Hospital, London, UK, and Pediatric Heart Center, Queen Sirikit National Institute of Child Health, Bangkok, Thailand. Data on patient characteristics, clinical and imaging outcomes, and follow-up status were collected retrospectively. RESULTS:During the studied period, 56 (96.6%) patients had a successful PPVI out of 58 attempted procedures. One attempt was unsuccessful, and one patient experienced valve migration, both requiring surgical intervention. There were no early or late deaths, and no patients developed valve stenosis or severe PR. Additionally, none of the patients experienced infective endocarditis or significant ventricular arrhythmias. Fluoroscopic evaluation at 6-12 months revealed wire frame fractures in 13 patients (23.2%), typically in the proximal flare of the valve; however, these fractures did not affect the valve function. Atrial arrhythmias occurred in two patients (3.5%), one of whom was managed medically and the other underwent successful ablation. The cohort of patients showed a significant decrease in PR on transthoracic echocardiography and a significant reduction in indexed right ventricular end-diastolic volumes and pulmonary regurgitant fraction by cardiac magnetic resonance imaging at between 6 and 12 months. These results were sustained on serial follow-up. CONCLUSION:VenusP-valve implantation is associated with excellent early and mid-term outcomes over a 5-10 year period, with no major complications related to valve function. However, longer-term follow-up is required to further assess its performance and longevity.

Transcatheter closure of sinus venosus defects (SVD) is an emerging alternative to surgery, however, concerns remain regarding growth potential in paediatric patients treated with fixed-diameter stents. This retrospective study included individuals younger than 18 years from 12 centres. SVD closure was performed using covered stents after demonstration of right upper pulmonary vein redirection during balloon interrogation. Complete closure without significant residual flow was defined as procedural success. Major complications were those necessitating surgical intervention, whereas minor complications were managed intraprocedurally. Among 54 patients < 18 years, 17 had bilateral superior vena cava and six had a high-draining vein. The majority (37) underwent single-stent placement; others required multiple stents. Procedural success was 98.1

Sinus venosus defect (SVD) is a rare congenital heart anomaly characterised by an abnormal communication between the atria, often associated with partial anomalous pulmonary venous connection (PAPVC). Traditional surgical repair carries significant risks, prompting exploration into less invasive transcatheter approaches.This study aims to evaluate the efficacy and safety of a 12-zig covered Cheatham-platinum stent for the correction of SVD, particularly in patients with enlarged superior vena caval-right atrial (SVC-RA) junctions unsuitable for standard stenting techniques.A retrospective analysis was conducted on five symptomatic patients treated with the 12-zig CP stent across two institutions. Preprocedural imaging, including echocardiograms, cardiac MRIs, and CT angiograms was performed to assess right ventricular function and define anatomical relationships. The procedures were guided by transoesophageal echocardiography (TOE) and involved balloon sizing to ensure optimal stent placement. All five patients (80% male, median age 59 years) successfully underwent stent implantation. A second stent was required in three cases due to residual leaks, which were effectively sealed, and in one case for stent stability. No procedural complications were reported, and all patients experienced symptomatic improvement at follow-up, with imaging confirming stable stent positions. The 12-zig CP stent demonstrates feasibility in the percutaneous treatment of highly selected patients with SVD, allowing for effective closure in complex anatomies, including large SVC-RA junctions. This study underscores the potential of advanced imaging techniques and tailored interventions in enhancing patient outcomes with complex congenital heart disease previously unsuitable for standard transcatheter approaches.

BACKGROUND:Long QT syndrome (LQTS) is primarily an inherited condition associated with the risk of sudden cardiac death. Due to variable phenotypic expression, a prolonged QT interval on a 12-lead ECG is not always present. LQTS may present in the fetus with persistent bradycardia, including sinus bradycardia or functional 2:1 atrioventricular block. We report our experience of persistent fetal bradycardia prompting parental assessment for congenital LQTS. METHODS:From January 1, 2018 to November 1, 2023, 20 parents (20 mothers; 20 fathers) of fetuses presenting with persistent bradycardia and suspected congenital LQTS were assessed. Autoimmune-mediated atrioventricular block, diagnosed in the presence of maternal anti-Ro/anti-La antibodies, and fetuses with ventricular tachycardia were excluded. Parental ECGs were acquired in the remainder, with comprehensive evaluation, including genomic testing, performed in 12 mothers and 11 fathers. RESULTS:Among 20 fetuses, 16 had sinus bradycardia and 4 had 2:1 atrioventricular block (intermittent=2; persistent=2). Pathogenic LQTS genetic variants were found in 11 fetuses (KCNQ1=8; KCNE1=1; KCNH2=1; CALM2 [calmodulin 2]=1), 9 mothers (KCNQ1=7; KCNE1=1; KCNH2=1) and 1 father (KCNQ1=1). Maternal corrected QT interval was higher in those with pathogenic variants compared with those who did not undergo genomic testing (456.9±11.6 versus 425.9±28.7 ms, P=0.009) but <400 ms in the paternal carrier. After review, 5 mothers with pathogenic variants were commenced on β-blockers (prepartum=4; postpartum=1). Provocation testing with a treadmill exercise test led to the initiation of β-blockade postnatally in one further case. CONCLUSIONS:The first indication of parental LQTS may be persistent fetal bradycardia. This should prompt consideration of this diagnosis even with a normal maternal corrected QT interval and lead to the initiation of specific management strategies for pregnancy, delivery, and the postpartum period before the results of genomic testing are available.

OBJECTIVES:To assess short- and medium-term outcomes of VenusP-valve implantation in the pulmonary position in the paediatric population. BACKGROUND:Percutaneous pulmonary valve implantation is now an established alternative to surgical pulmonary valve replacement, especially in those with conduits in the right ventricular outflow tract. The VenusP-valve™ (Venus Medtech, Shanghai, China) has demonstrated early efficacy in the adult population with larger conduit-free right ventricular outflow tracts. However, its use in children has not been well described. METHODS:Retrospective review of patients under 18 years of age undergoing VenusP-valve implantation at a single institution between June 2015 and February 2023. RESULTS:Fifteen patients under the age of 18 years underwent VenusP-valve™ implantation. All had severe pulmonary regurgitation and fulfilled accepted criteria for pulmonary valve implantation. Mean age at valve implantation was 14.1 (range 9.8-17.9) years, and mean weight was 54.9 (34.0-98.5) kg. The valve was deployed successfully in all the patients. The valve diameter and length ranged between 28-36 mm and 25-35 mm, respectively. Mean follow-up was 3.4 (0.5-8.1) years. At follow-up, twelve patients have undergone magnetic resonance imaging MRI as part of the regular surveillance. Indexed right ventricular end-diastolic volume improved from 157.8 (140.0-197.0) ml/m2 to 117.6 (91.0-152.0) ml/m2 (p = 0.004). Pulmonary regurgitation fraction had reduced from a mean of 44.3 (31.0-60.0) % to 3.6 (0.0-15.0) % (p = 0.003). CONCLUSION:This study demonstrates the safety and feasibility of the VenusP-valve implantation in children. Medium-term follow-up suggests that valve implantation is associated with a reduction in the degree of pulmonary regurgitation and right ventricular end-diastolic volume.

INTRODUCTION AND OBJECTIVES:Transcatheter patent ductus arteriosus (PDA) closure is safe in<2-kg infants and in≥6-kg patients, but major safety concerns remain when applied to the intermediate weight range. We aimed to assess outcomes of transcatheter PDA closure in 2- to 6-kg infants. METHODS:An international, multicenter, retrospective cohort study was conducted in 31 tertiary hospitals in 17 countries between 2000 and 2023, investigating all infants who underwent attempted transcatheter PDA closure with a procedural weight of 2-to-6kg. RESULTS:Attempted transcatheter PDA closure was performed in 1231 infants (median [Q1-Q3] weight, 4747 [3700-5300] g; median age, 132 [83-194] days; ex-preterm, n=581 [56.8%]) with a 95.0% success rate. A composite outcome of procedural failure or major adverse events was observed in 173 (14%) patients, including device embolization in 64 (3.7%), device-induced left pulmonary artery stenosis in 47 (2.7%), and procedural death in 2 (0.2%). Logistic regression model analysis identified a 2- to 3.9-kg procedural weight, increased pulmonary artery pressure, and window-type or tubular ductal morphologies as independent predictors of the composite outcome. Based on propensity score matching analysis, 2- to 3.9-kg infants had a risk ratio of 2.19 (95%CI, 1.25-3.83) for experiencing the composite outcome, compared with 4- to 5.9-kg infants. CONCLUSIONS:Transcatheter PDA closure in 2- to 6-kg infants was feasible in most patients. Procedural failure or major adverse events occurred in 14% and several independent risk factors were identified, including the 2- to 3.9-kg weight range identified as a higher-risk subgroup. These findings may improve risk stratification and the decision-making process.

Tetralogy of Fallot (ToF) is the most common cyanotic congenital heart disease, frequently diagnosed prenatally. To enhance understanding, we reviewed 18 years of our institutional outcomes for patients with classic ToF. There were 410 patients of whom 233/410 (56.8

BACKGROUND:Covered stent correction for a sinus venosus atrial septal defect (SVASD) was first performed in 2009. This innovative approach was initially viewed as experimental and was reserved for highly selected patients with unusual anatomic variants. In 2016, increasing numbers of procedures began to be performed, and in several centers, it is now offered as a standard of care option alongside surgical repair. However, covered stent correction for SVASD is not recognized by regulatory authorities, and in the minds of many pediatric and adult congenital cardiologists and surgeons, the condition is viewed as treatable only by cardiac surgery with cardiopulmonary bypass. METHODS:In April 2023, all centers identified from international conferences, publications, and colleague networks to be undertaking covered stent correction for SVASD were invited to participate in a retrospective audit of their procedures. RESULTS:Data were received on 381 patients from 54 units over a 12-year period with 90% of procedures being performed over the past 5 years. Balloon-expandable stents (8 types) were used in the majority; self-expanding stents (4 types) were used in 4.5%. The commonest stent was the 10-zig covered Cheatham Platinum stent in 62% of cases. In 10 procedures, the stent embolized requiring surgical retrieval and repair of the defect, resulting in technically successful implantation in 371 of 381 (97.4%). Major complications (surgical drainage of tamponade, pacemaker implantation, surgery for pulmonary vein occlusion, and late stent removal) occurred in 5 patients (1.3%). Repeat catheterization to correct residual leaks was required in 7 patients (1.8%). Thus, 359 of 381 patients (94.2%) had successful correction without major complications or additional catheter interventions. CONCLUSIONS:This article details the exponential uptake of covered stent correction for SVASD during the past 5 years. Cardiopulmonary bypass was avoided in the majority of patients, and major complications were infrequent. Prospective registries with standardized definitions, inclusion criteria, and follow-up and comparative studies with surgery are now required to help support the extension of covered stent correction as an alternative standard-of-care option for patients with an SVASD.

BACKGROUND:Fetal tachycardias can cause adverse fetal outcomes including ventricular dysfunction, hydrops, and fetal demise. Postnatally, ECG is the gold standard, but, in fetal practice, echocardiography is used most frequently to diagnose and monitor fetal arrhythmias. Noninvasive extraction of the fetal ECG (fECG) may provide additional information about the electrophysiological mechanism and monitoring of intermittent arrhythmias. Signal processing advances could provide improved data quality impacting clinical translation. The aim of this study was to assess the fetus with known or suspected tachycardia using noninvasive abdominal fECG and correlate results with fetal echocardiography and postnatal ECG. METHODS:Prospective recruitment of pregnant participants with known or suspected fetal tachycardia in a tertiary fetal cardiology unit. Overnight fECG recording at home using the MonicaAN24 monitor was performed. Data processing using bespoke MATLAB scripts was undertaken to produce fetal heart rate and beat-to-beat rhythm strips. Comparison of fECG data with clinical data obtained using echocardiography and postnatal findings. Data are presented as median (interquartile range; range). RESULTS:Fifteen participants undertook 1 to 4 fECG recordings, giving a total of 23 recordings. Gestational age was 28.9 (23.9-34.3; 21-39.1) weeks. Duration of recording was 512 (380-609; 5-1259) minutes. Intermittent tachycardia was demonstrated on fetal heart rate graphs. Rhythm strips correctly identified short-ventriculoatrial and long-ventriculoatrial tachycardia, atrial flutter, and sinus rhythm with findings correlating with echocardiography. Postnatal ECG correlation was possible in 3. CONCLUSIONS:We have shown that rhythm strips of fECG signals can be extracted and correctly identify the electrical mechanism of arrhythmia in cases of fetal tachycardia. The potential to monitor fetal heart rate over a prolonged period is an advantage over current monitoring strategies for documentation of intermittent arrhythmias and gauging the response to medical therapy. These data will enable research to focus on improvement in signal quality, assessment of other arrhythmia subtypes, and real-time ambulatory monitoring of the fetal rhythm.

To provide an overview of fluoroscopy-free transcatheter atrial septal defect (ASD) closure and introduce a simplified approach that avoids pulmonary vein instrumentation. Since the first reported fluoroscopy-free ASD closure 24 years ago, only a few small series have described this technique. We present a simplified and less cumbersome approach to encourage wider adoption of the fluoroscopy-free method to suitable ASD anatomy. Fluoroscopy free ASD closure was performed in 9 patients using the conventional technique (Group 1) and 23 patients using our simplified approach of direct placement of the device into the defect (Group 2). Median age and weight were 28 years, 53 kg in Group 1 (range: 5–52 years, 22–88 kg) and 36 years, 66 kg in Group 2 (range: 4–76 years, 16–115 kg). Devices were successfully implanted in all patients, with a median device size of 21 mm (Group 1: 9–36 mm, Group 2: 10–33 mm). Procedural time was 47 min for Group 1 and 35 min for Group 2 (p = 0.09). Length of hospital stay was similar in both groups. There were no acute or long-term complications and no need for reintervention. Transcatheter ASD closure without the use of fluoroscopy using the simplified approach is safe and effective, offers a shorter procedure duration and minimises instrumentation within the left atrium and pulmonary veins. Patient selection is key and with greater experience, this procedure may be applicable to a wider selection of ASD anatomy.

Objective: Short-term RCTs have demonstrated that MPH-treatment significantly reduces ADHD-symptoms, but is also associated with adverse events, including sleep problems. However, data on long-term effects of MPH on sleep remain limited.Methods: We performed a 2-year naturalistic prospective pharmacovigilance multicentre study. Participants were recruited into three groups: ADHD patients intending to start MPH-treatment (MPH-group), those not intending to use ADHD-medication (no-MPH-group), and a non-ADHD control-group. Sleep problems were assessed with the Children's-Sleep-Habits-Questionnaire (CSHQ).Results: 1,410 participants were enrolled. Baseline mean CSHQ-total-sleep-scores could be considered clinically significant for the MPH-group and the no-MPH-group, but not for controls. The only group to show a significant increase in any aspect of sleep from baseline to 24-months was the control-group. Comparing the MPH- to the no-MPH-group no differences in total-sleep-score changes were found.Conclusion: Our findings support that sleep-problems are common in ADHD, but don't suggest significant negative long-term effects of MPH on sleep.

Carcinoid heart disease is an important complication of neuroendocrine tumors that may lead to significant morbidity and mortality. Right-sided heart valve involvement with consequent valve dysfunction is one of the common manifestations. Patients often have multiple, significant comorbidities with advanced metastatic disease and, as such, may not be suitable for surgical valve replacement due to excessive risk. Transcatheter valve replacement using balloon-expandable valves has been the mainstay of management for these patients, particularly with stenotic lesions but there is limited experience in patients with pulmonary regurgitation and dilated pulmonary arteries outside the dimensions that would be suitable for these valves. We report three successful cases of percutaneous pulmonary valve implantation with the VenusP-valve, a large self-expanding valve platform, and highlight the technical aspects and challenges specific to treatment of pulmonary regurgitation in patients with carcinoid heart disease. Percutaneous pulmonary valve implantation, using the VenusP-valve, may be considered an effective treatment in this patient group.

The use of conduction system pacing (CSP) in adults with congenital heart disease (CHD) is growing, however data remain limited. In patients with congenitally corrected transposition of the great arteries following the double switch operation, existing CSP tools and techniques require modification to allow for the anterior displacement of the atrioventricular node and proximal conduction system in addition to navigating the tortuous route of the atrial redirection. We report the successful use of CSP focusing on the technique of delivery tool modification to allow stability on the basal septum for deployment to the area of the distal His bundle and proximal left bundle branch.

BACKGROUND:Covered stent correction (CSC) of a superior sinus venosus atrial septal defect is an alternative to surgery in selected patients, but anatomic variation means that assessment for CSC requires a 3-dimensional anatomic understanding. Heart VR is a virtual reality (VR) system that rapidly displays and renders multimodality imaging without prior image segmentation. The aim of this study was to evaluate the performance of the Heart VR system to assess patient suitability for CSC. METHODS:In a blinded fashion, 2 interventionalists reviewed preprocedural computed tomography scans using Heart VR to assess the feasibility of CSC, including the potential need for pulmonary vein protection. The total review time using VR was recorded. RESULTS:Using conventional imaging, 15 patients were deemed suitable for CSC, but at catheterization, 3 cases were unsuitable. Using VR, when both interventionalists agreed that a case was suitable for CSC (n=12), all proved technically feasible. In the 3 cases that were unsuitable for CSC, the interventionalists using VR were either uncertain (n=1) or did not agree on suitability (n=2). The strategy for pulmonary vein protection was correctly identified by interventionalist 1 and 2 in 9/12 and 8/12 cases, respectively. In cases where pulmonary vein protection was required intraprocedurally (n=5), this was correctly identified using Heart VR. Using VR, in 3 cases it was determined that pulmonary vein protection would be required, but this was not the case on balloon interrogation. VR data loading and review times were 82 seconds and 7 minutes, respectively. Verbal feedback indicated that Heart VR assisted in the assessment of case suitability. CONCLUSIONS:Heart VR is a rapid and effective tool for predicting suitability for CSC in patients with a superior sinus venosus atrial septal defect and could be a feasible alternative to segmented virtual or physical 3-dimensional models.

Background Atrioventricular block is common with adult congenital heart disease and pacemaker implantation is challenging. Atrioventricular synchronous pacing is important for better haemodynamics. This case reports the implantation of a dual-chamber leadless pacemaker in a patient with univentricular heart physiology and contributes to the literature regarding the management option in complex adult congenital heart disease patients with conduction abnormalities.Case summary A 25-year-old male with double inlet left ventricular, transposition of great arteries, hypoplastic aortic arch receive multiple surgeries including the Glenn shunt at the age of 1. He presented with 2:1 and 3:1 heart block at the age of 13 with a transvenous dual-chamber pacemaker implanted by pacing the superior vena cava stump and puncturing the Glenn shunt for the ventricular lead. A decade later, lead malfunctioned and the patient progressed to complete heart block. A subcutaneous implantable cardioverter defibrillator was implanted when he was 23 for monomorphic ventricular tachycardia. Given the anticipated challenges with transvenous lead extraction and epicardial pacemaker implantation, we implanted the novel dual-chamber leadless pacemakers which resulted in satisfactory atrioventricular synchronous pacing performance immediately post-op and 2 weeks after the procedure.Discussion We present a case of a novel dual-chamber leadless pacemaker implantation to maintain atrioventricular synchrony in the patient with complete heart block and univentricular physiology. This case illustrates an additional pacing option in complex adult congenital heart to maintain atrioventricular synchrony.

Ablation of accessory pathways in patients with Ebstein's anomaly can be challenging. Despite increasing experience and advances in mapping technology, success is limited and recurrence rates can be high. To date, high-density electroanatomic mapping has not been studied in this anatomical substrate. We present a pediatric case of Ebstein's anomaly in which high-density mapping in Ebstein's anomaly was a useful additional tool to improve the outcome of catheter ablation.