Publications by authors named "Kammeraad J"

Aims: (i) Investigate the prevalence of hypertrophic cardiomyopathy (HCM) in individuals with pathogenic/likely pathogenic (P/LP) gene variants detected through family cascade testing in relatives, and (ii) evaluate phenotypic progression in genotype-positive phenotype-negative (G+/P-) individuals during follow-up.

Results: From 2000 to 2023, 273 individuals underwent cardiologic evaluation following P/LP variant detection through family screening. Upon initial evaluation, HCM was diagnosed in 128 (47 %) individuals.

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Background: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare, potentially life-threatening genetic heart disease. Nonselective beta-blockers (BBs) are highly effective in reducing CPVT-triggered arrhythmic events. However, some patients suffer from unacceptable BB side effects and might require strategies without a BB.

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Article Synopsis
  • - The study examines how secondary genetic variants can influence the clinical features of individuals with primary disease-causing variants, suggesting that these modifiers play a significant role in disease expression.
  • - Specifically focusing on the 16p12.1 deletion, researchers identified various rare and common variants that predisposed individuals to specific developmental issues, such as neurological defects and microcephaly.
  • - By analyzing data from different cohorts, the findings indicate that the effects of primary and secondary variants on phenotype vary depending on the specific primary variant involved, highlighting the need for personalized approaches in treatment.
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Background: Frequent premature ventricular contractions (PVCs) in children are usually considered benign. Symptoms and left ventricular dysfunction are indications for treatment with antiarrhythmic drugs.

Objective: This study aimed to evaluate the efficacy of flecainide vs metoprolol in reducing PVCs in children.

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Background: Catecholaminergic polymorphic ventricular tachycardia (CPVT) may cause sudden cardiac death (SCD) despite medical therapy. Therefore, implantable cardioverter-defibrillators (ICDs) are commonly advised. However, there is limited data on the outcomes of ICD use in children.

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Background: Current cohorts of patients with idiopathic ventricular fibrillation (IVF) primarily include adult-onset patients. Underlying causes of sudden cardiac arrest vary with age; therefore, underlying causes and disease course may differ for adolescent-onset vs adult-onset patients.

Objective: The purpose of this study was to compare adolescent-onset with adult-onset patients having an initially unexplained cause of VF.

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Aims: In patients with catecholaminergic polymorphic ventricular tachycardia (CPVT), a rare inherited arrhythmia syndrome, arrhythmic events can be prevented by medication and lifestyle recommendations. In patients who experience breakthrough arrhythmic events, non-adherence plays an essential role. We aimed to investigate the incidence and potential reasons for non-adherence to medication and lifestyle recommendations in a large, international cohort of patients with CPVT.

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The Py-Conformational-Sampling (PyCoSa) technique is introduced as a systematic computational means to sample the configurational space of transition-metal-catalyzed stereoselective reactions. When applied to atroposelective Suzuki-Miyaura coupling to create axially chiral biaryl products, the results show a range of mechanistic possibilities that include multiple low-energy channels through which C-C bonds can be formed.

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Aims: To evaluate the effect of electro-anatomical mapping on success rate and fluoroscopy time in ablation of supraventricular tachycardia substrates in a large group of children.

Methods: Patients referred from multiple centres in the Netherlands and who received a first ablation for supraventricular tachycardia substrates in the Leiden University Medical Center between 2014 and 2020 were included in this retrospective cohort study. They were divided in procedures in patients with fluoroscopy and procedures in patients using electro-anatomical mapping.

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Single-electron transfer (SET) promotes a wide variety of interesting chemical transformations, but modeling of SET requires a careful treatment of electronic and solvent effects to give meaningful insight. Therefore, a combined constrained density functional theory and molecular mechanics (CDFT/MM) tool is introduced specifically for SET-initiated reactions. Mechanisms for two radical-polar crossover reactions involving the organic electron donors tetrakis(dimethylamino)ethylene (TDAE) and tetrathiafulvalene (TTF) were studied with the new tool.

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Aim: This study aimed to investigate trends over time in pre-hospital factors for pediatric out-of-hospital cardiac arrest (pOHCA) and long-term neurological and neuropsychological outcomes. These have not been described before in large populations.

Methods: Non-traumatic arrest patients, 1 day-17 years old, presented to the Sophia Children's Hospital from January 2002 to December 2020, were eligible for inclusion.

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Unlabelled: Sudden cardiac arrest (SCA) studies are often population-based, limited to sudden cardiac death, and excluding infants. To guide prevention opportunities, it is essential to be informed of pediatric SCA etiologies. Unfortunately, etiologies frequently remain unresolved.

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Background: In severely affected patients with catecholaminergic polymorphic ventricular tachycardia, beta-blockers are often insufficiently protective. The purpose of this study was to evaluate whether flecainide is associated with a lower incidence of arrhythmic events (AEs) when added to beta-blockers in a large cohort of patients with catecholaminergic polymorphic ventricular tachycardia.

Methods: From 2 international registries, this multicenter case cross-over study included patients with a clinical or genetic diagnosis of catecholaminergic polymorphic ventricular tachycardia in whom flecainide was added to beta-blocker therapy.

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Sudden cardiac death is the most common mode of death during childhood and adolescence in hypertrophic cardiomyopathy, and identifying those individuals at highest risk is a major aspect of clinical care. The mainstay of preventative therapy is the implantable cardioverter-defibrillator, which has been shown to be effective at terminating malignant ventricular arrhythmias in children with hypertrophic cardiomyopathy but can be associated with substantial morbidity. Accurate identification of those children at highest risk who would benefit most from implantable cardioverter-defibrillator implantation while minimising the risk of complications is, therefore, essential.

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Article Synopsis
  • Heat-bath configuration interaction (HCI) is an efficient method for quantum calculations that closely approximates the full CI limit while reducing computational costs.
  • Recent improvements to the HCI algorithm enhance speed, parallel efficiency, and memory usage, allowing for the study of complex systems with a huge number of determinants.
  • The new implementation achieved significant parallel efficiency in benchmarks and was specifically tested on the triplet-quintet gap of the complex [FeO(NH)].
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Early post-operative sinus node dysfunction (SND) is common in paediatric patients undergoing surgical correction of congenital heart defects (CHD). At present, the pathophysiology of these arrhythmias is incompletely understood. In this case series, we present three paediatric patients in whom we performed intraoperative epicardial mapping and who developed early post-operative SND.

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Article Synopsis
  • Brugada syndrome (BrS) is a rare inherited arrhythmia that can cause life-threatening symptoms in children, especially during fever, with a higher incidence of SCN5A variants in kids compared to adults.
  • Current diagnostic and follow-up practices for children with BrS significantly differ across medical centers, prompting the need for a unified approach outlined in this consensus statement for the Netherlands.
  • Key recommendations include using specific ECG patterns for diagnosis, strict guidelines on drug testing and genetic testing (focused on the SCN5A gene), and necessary precautions like avoiding certain medications and managing fever to prevent severe complications.
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Conformer-RL is an open-source Python package for applying deep reinforcement learning (RL) to the task of generating a diverse set of low-energy conformations for a single molecule. The library features a simple interface to train a deep RL conformer generation model on any covalently bonded molecule or polymer, including most drug-like molecules. Under the hood, it implements state-of-the-art RL algorithms and graph neural network architectures tuned specifically for molecular structures.

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Transfer and active learning have the potential to accelerate the development of new chemical reactions, using prior data and new experiments to inform models that adapt to the target area of interest. This article shows how specifically tuned machine learning models, based on random forest classifiers, can expand the applicability of Pd-catalyzed cross-coupling reactions to types of nucleophiles unknown to the model. First, model transfer is shown to be effective when reaction mechanisms and substrates are closely related, even when models are trained on relatively small numbers of data points.

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Catheter ablation (CA) is an important treatment option for ventricular arrhythmias (VA) in pediatric cardiology. Currently, various CA techniques are available, including remote magnetic navigation (RMN)-guided radiofrequency (RF) ablation. However, no studies evaluate RMN-guided ablative therapy outcomes in children with VA yet.

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Background: Symptomatic children with catecholaminergic polymorphic ventricular tachycardia (CPVT) are at risk for recurrent arrhythmic events. β-Blockers decrease this risk, but studies comparing individual β-blockers in sizeable cohorts are lacking. We aimed to assess the association between risk for arrhythmic events and type of β-blocker in a large cohort of symptomatic children with CPVT.

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Article Synopsis
  • Catheter ablation (CA) is the preferred treatment for tachyarrhythmia in children, but there are limited large studies comparing the long-term effectiveness of different CA techniques (remote magnetic navigation, manual-guided RF, and manual-guided cryoablation) for atrioventricular reentry tachycardia (AVRT) and atrioventricular nodal reentry tachycardia (AVNRT).
  • This study analyzed 223 pediatric patients and found that remote magnetic navigation (RMN) led to significantly lower long-term recurrence rates of tachyarrhythmia compared to manual-guided RF (MAN) and manual-guided cryoablation (CRYO) after an average follow-up of 5.
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