Leiden University Medical Center Research Articles

An innovative method to strengthen evidence for potential drug safety signals using Electronic Health Records

Reports from spontaneous reporting systems (SRS) are hypothesis generating. Additional evidence such as more reports is required to determine whether the generated drug-event associations are in fact safety signals. However, underreporting of adverse drug reactions (ADRs) delays signal detection. Through the use of natural language processing, different sources of real-world data can be used to proactively collect additional evidence for potential safety signals. This study aims to explore the feasibility of using Electronic Health Records (EHRs) to identify additional cases based on initial indications from spontaneous ADR reports, with the goal of strengthening the evidence base for potential safety signals. For two confirmed and two potential signals generated by the SRS of the Netherlands Pharmacovigilance Centre Lareb, targeted searches in the EHR of the Leiden University Medical Centre were performed using a text-mining based tool, CTcue. The search for additional cases was done by constructing and running queries in the structured and free-text fields of the EHRs. We identified at least five additional cases for the confirmed signals and one additional case for each potential safety signal. The majority of the identified cases for the confirmed signals were documented in the EHRs before signal detection by the Dutch Medicines Evaluation Board. The identified cases for the potential signals were reported to Lareb as further evidence for signal detection. Our findings highlight the feasibility of performing targeted searches in the EHR based on an underlying hypothesis to provide further evidence for signal generation.

Validation of a prediction model for early reconnection after cryoballoon ablation.

We previously developed an early reconnection/dormant conduction (ERC) prediction model for cryoballoon ablation to avoid a 30-min waiting period with adenosine infusion. We now aimed to validate this model based on time to isolation, number of unsuccessful cryo-applications, and nadir balloon temperature. Consecutive atrial fibrillation patients who underwent their first cryoballoon ablation in 2018-2019 at the Leiden University Medical Center were included. Model performance at the previous and at a new optimal cutoff value was determined. A total of 201 patients were included (85.57% paroxysmal AF, 139 male, median age 61years (IQR 53-69)). ERC was found in 35 of 201 included patients (17.41%) and in 41 of 774 veins (5.30%). In the present study population, the previous cutoff value of - 6.7 provided a sensitivity of 37.84% (previously 70%) and a specificity of 89.07% (previously 86%). Shifting the cutoff value to - 7.2 in both study populations resulted in a sensitivity of 72.50% and 72.97% and a specificity of 78.22% and 78.63% in data from the previous and present study respectively. Negative predictive values were 96.55% and 98.11%. Applying the model on the 101 patients of the present study with all necessary data for all veins resulted in 43 out of 101 patients (43%) not requiring a 30-min waiting period with adenosine testing. Two patients (2%) with ERC would have been missed when applying the model. The previously established ERC prediction model performs well, recommending its use for centers routinely using adenosine testing following PVI.

Knee-to-chest flexion manoeuvre to reduce respiratory distress after planned caesarean birth: a feasibility study

BackgroundPlanned caesarean section (CS) is a risk factor for neonatal respiratory distress caused by a greater volume of airway liquid in the absence of uterine contractions.Performing a newly conceptualised knee-to-chest...

Influence of initial misdiagnosis on mortality in patients with bacteraemia: propensity score matching and propensity score weighting analyses

BackgroundThe diagnostic process is a key element of medicine but it is complex and prone to errors. Infectious diseases are one of the three categories of diseases in which diagnostic errors can be most harmful to patients. In this study we aimed to estimate the effect of initial misdiagnosis of the source of infection in patients with bacteraemia on 14 day mortality using propensity score methods to adjust for confounding.MethodsData from a previously described longitudinal cohort of patients diagnosed with monobacterial bloodstream infection (BSI) at the Leiden University Medical Centre (LUMC) between 2013 and 2015 were used. Propensity score matching and inversed probability of treatment weighting (IPTW) were applied to correct for confounding. The average treatment effect on the treated (ATT), which in this study was the average effect of initial misdiagnosis on the misdiagnosed (AEMM), was estimated. Methodological issues that were encountered when applying propensity score methods were addressed by performing additional sensitivity analyses. Sensitivity analyses consisted of varying caliper in propensity score matching and using different truncated weights in inversed probability of treatment weighting.ResultsData of 887 patients were included in the study. Propensity scores ranged between 0.015 and 0.999 and 80 patients (9.9%) had a propensity score > 0.95. In the matched analyses, 35 of the 171 misdiagnosed patients died within 14 days (20.5%), versus 10 of the 171 correctly diagnosed patients (5.8%), yielding a difference of 14.6% (7.6%; 21.6%). In the total group of patients, the observed percentage of patients with an incorrect initial diagnosis that died within 14 days was 19.8% while propensity score reweighting estimated that their probability of dying would have been 6.5%, if they had been correctly diagnosed (difference 13.3% (95% CI 6.9%;19.6%)). After adjustment for all variables that showed disbalance in the propensity score a difference of 13.7% (7.4%; 19.9%) was estimated. Sensitivity analyses yielded similar results. However, performing weighted analyses without truncation yielded unstable results.ConclusionThus, we observed a substantial increase of 14 day mortality in initially misdiagnosed patients. Furthermore, several patients received propensity scores extremely close to one and were almost sure to be initially misdiagnosed.

Association between onychomycosis and ulcerative complications in patients with diabetes: a longitudinal cohort study in Dutch general practice

IntroductionDiabetic foot ulcers are feared complications of diabetes mellitus (DM), requiring extensive treatment and hospital admissions, ultimately leading to amputation and increased mortality. Different factors contribute to the development of...

Fluctuations of stress and resilience in healthcare workers during the COVID-19 pandemic: Insights and recommendations

BackgroundHealthcare workers (HCW) have faced unprecedented challenges during the COVID-19, with significant impact on their well-being. We aimed to monitor stress-related symptoms and resilience in HCW over time in relation to various factors during the COVID-19 pandemic. MethodsBetween June 2020 and May 2022, data was collected among HCW of Leiden University Medical Centre (LUMC) through a digital self-monitoring application. The application included a 14-items self-monitoring tool (i.e., 7-items on Supporting factors, 7-items on Stressful burden), and a set of validated questionnaires (i.e., the Copenhagen Burnout Inventory (CBI), Impact of Event Scale – Revised (IES-R), Resilience Evaluation Scale (RES), and Depression Anxiety and Stress Scale (DASS-21). ResultsThe self-monitoring tool and validated questionnaires were completed by 1070 and 413 participants respectively. Mean stress-related symptom scores (as measured by the self-monitoring, CBI, IES-R, and DASS-21) exhibited significant changes over time (all p’s < 0.001), which correlated with the waves of COVID-19 patients admitted and the national COVID-19 mortality rate (all p’s < 0.005). Resilience, as measured by the RES, showed a significant decrease from the start of data collection onwards (p = 0.001), whereas supporting factors showed significant decreases the first few months, followed by fluctuations after January 2021 (p = 0.02). LimitationsSelection bias may have arisen as those participating may have been more concerned with the burden on mental wellbeing. ConclusionsThe current study underscores the need for active psychosocial support for all HCW particularly during periods of increased admissions due to pandemics.

Sensitivity of the Boston criteria version 2.0 in Dutch-type hereditary cerebral amyloid angiopathy.

The revised Boston criteria v2.0 for cerebral amyloid angiopathy (CAA) add two radiological markers to the existing criteria: severe visible perivascular spaces in the centrum semiovale and white matter hyperintensities (WMHs) in a multispot pattern. This study aims to determine the sensitivity of the updated criteria in mutation carriers with Dutch-type hereditary CAA (D-CAA) in an early and later disease stage. In this cross-sectional study, we included presymptomatic and symptomatic D-CAA mutation carriers from our prospective natural history study (AURORA) at the Leiden University Medical Center between 2018 and 2021. 3-Tesla scans were assessed for CAA-related magnetic resonance imaging (MRI) markers. We compared the sensitivity of the Boston criteria v2.0 to the previously used modified Boston criteria v1.5. We included 64 D-CAA mutation carriers (mean age 49 years, 55% women, 55% presymptomatic). At least one white matter (WM) feature was seen in 55/64 mutation carriers (86%: 74% presymptomatic, 100% symptomatic). Fifteen (23%) mutation carriers, all presymptomatic, showed only WM features and no hemorrhagic markers. The sensitivity for probable CAA was similar between the new and the previous criteria: 11/35 (31%) in presymptomatic mutation carriers and 29/29 (100%) in symptomatic mutation carriers. The sensitivity for possible CAA in presymptomatic mutation carriers increased from 0/35 (0%) to 15/35 (43%) with the new criteria. The Boston criteria v2.0 increase the sensitivity for detecting possible CAA in presymptomatic D-CAA mutation carriers and, therefore, improve the detection of the early phase of CAA.

Older patients' experiences with and attitudes towards an oncogeriatric pathway: A qualitative study

IntroductionTo tailor treatment for older patients with cancer, an oncogeriatric care pathway has been developed in the Leiden University Medical Center. In this care pathway a geriatric assessment is performed and preferences concerning cancer treatment options are discussed. This study aimed to explore patient experiences with and attitudes towards this pathway. Materials and MethodsA qualitative study was performed using an exploratory descriptive approach. Individual face-to-face semi-structured interviews were conducted with older patients (≥70 years) who had followed the oncogeriatric care pathway in the six months prior to the interview. The interviews were audio-recorded and transcribed verbatim. The transcripts were analyzed inductively using thematic analysis. ResultsAfter interviews with 14 patients with a median age of 80 years, three main themes were identified. (1) Patients' positive experiences with the oncogeriatric pathway: Patients appreciated the attitudes of the healthcare professionals and felt heard and understood. (2) Unmet information needs about the oncogeriatric care pathway: Patients experienced a lack of information about the aim and process. (3) Incomplete information for decision-making: Most patients were satisfied with decision-making process. However, treatment decisions had often been made before oncogeriatric consultation. No explicit naming and explaining of different available treatment options had been provided, nor had risk of physical or cognitive decline during and after treatment been addressed. DiscussionOlder patients had predominately positive attitudes towards the oncogeriatric care pathway. Most patients were satisfied with the treatment decision. Providing information on the aim and process of the care pathway, available treatment options, and treatment-related risks of cognitive and physical decline may further improve the oncogeriatric care pathway and the decision-making process.

Defining the imaging diagnostic criteria for adult chronic non-bacterial osteitis.

Osteitis of the sternocostoclavicular (SCC) region, referred to as sternocostoclavicular hyperostosis (SCCH), is the clinical expression of chronic non-bacterial osteitis (CNO) in adults with this rare chronic auto-inflammatory disorder of the axial skeleton. The diagnosis is based on distinctive computerized tomography (CT) features of sclerosis and hyperostosis of the SCC region, and local increases in osteoid formation visualized by high radiopharmacon uptake on skeletal scintigraphy but clear radiologic diagnostic criteria are lacking. In a cross-sectional study, CT scans and whole-body skeletal scintigraphy images obtained in 169 patients seen at the Center for Bone Quality of the Leiden University Medical Center between 2008 and 2018 with a suspected diagnosis of CNO of the SCC region were re-evaluated by 2 skeletal radiologists and 2 nuclear physicians. The diagnosis was confirmed in 118 (70%) predominantly female patients (n= 103, 89.2%); median age at first symptoms 45years (range 20-73). The diagnosis was excluded in the remaining 51 "non-CNO" patients. Increased radiopharmacon uptake at the SCC region was observed in 82% CNO patients, with the manubrium sterni having the highest predictive ability to discriminate on both imaging modalities. The prevalence of sclerosis of the clavicles, manubrium and first ribs was significantly higher in CNO patients (P< 0.001). Hyperostosis was not observed in non-CNO patients. 46 CNO versus only 2 non-CNO patients had costoclavicular ligament calcification. Our findings identify CT scan features of sclerosis and hyperostosis of manubrium sterni, medial end of clavicles and first ribs, and calcification of costoclavicular ligaments, associated with increased tracer uptake on skeletal scintigraphy at the SCC region, specifically manubrium sterni, as well-defined imaging diagnostic criteria for adult CNO. Pitfalls encountered in the diagnosis of CNO are highlighted. These defined imaging diagnostic criteria for adult CNO should facilitate the diagnosis of this rare auto-inflammatory bone disease across the spectrum of its early to late stages.

Evaluation of Quality of Life and Treatment Satisfaction in Newly Diagnosed Cutaneous T-Cell Lymphoma Patients.

Little is known about the impact of MF on quality of life (QoL) in newly diagnosed patients. To describe the impact of the MF diagnosis on QoL, patient expectations, and treatment satisfaction over the first 6 months after diagnosis. Outcomes of this prospective cohort study of newly diagnosed MF patients conducted between 2020 and 2022 at the Leiden University Medical Center included the Skindex-29, RAND-12 Health Survey, degree of itch, pain, and fatigue (Visual Analogue Scale (VAS)), patient expectations, and Client Satisfaction Questionnaire-8 (CSQ-8), measured at baseline and after six months. A total of 28 patients with MF were included. At baseline, 66% (n = 18) "strongly-totally" expected positive effects of the treatment. At the time of diagnosis, 28% of the patients (n = 8) were moderately to severely affected. There was no statistical change in the Skindex-29 score sum score (20 [10-34] vs. 20 [9-36]; p = 0.81) or in the other three subdomains, the RAND-12 scores, and the VAS itch, pain, and fatigue over time. Treatment satisfaction was high overall. Despite that the newly diagnosed MF patients anticipate a positive treatment effect, few improvements in QoL and symptom reduction were found. These data can be used for adequate expectation management and provide a rationale for further evaluation of treatment regimens in these patients.

Compliance with maternal sepsis guidelines in a tertiary hospital in the Netherlands

ABSTRACT Objectives Sepsis is a common cause of maternal mortality and morbidity. Early detection and rapid management are essential. In this study, we evaluate the compliance with the implemented maternity-specific Early Warning Score (EWS), Rapid Response Team (RRT) protocol and the Surviving Sepsis Campaign (SSC) Hour-1 Bundle in a tertiary hospital in the Netherlands. Methods We performed a retrospective patient chart review from July 2019 to June 2020 at the Leiden University Medical Centre. We included women who received therapeutic antibiotics and were admitted for at least 24 hours. Results We included 240 women: ten were admitted twice and one woman three times, comprising 252 admissions. A clinical diagnosis of sepsis was made in 22 women. The EWS was used in 29% (n = 73/252) of admissions. Recommendations on the follow-up of the EWS were carried out in 53% (n = 46/87). Compliance with the RRT protocol was highest for assessment by a medical doctor within 30 minutes (n = 98/117, 84%) and lowest for RRT involvement (n = 7/23, 30%). In women with sepsis, compliance with the SSC Bundle was highest for acquiring blood cultures (n = 19/22, 85%), while only 64% (n = 14/22) received antibiotics within 60 minutes of the sepsis diagnosis. Conclusion The adherence to the maternity-specific EWS and the SSC Hour-1 bundle was insufficient, even within this tertiary setting in a high-income country.

Using the providers’ perspective on video review of neonatal procedures to create a roadmap: a qualitative study

ObjectiveTo examine the providers’ perceptions and experiences on implementation of video review (VR) of procedures in the neonatal intensive care unit (NICU).DesignQualitative study using semi-structured interviews with neonatal care providers...

Design thinking in medical education to tackle real world healthcare problems: The MasterMinds Challenge

Educational challenge Medical education must equip future professionals with the necessary skills to navigate the complex healthcare landscape. Clinical knowledge is essential, and critical and creative thinking skills are vital to meet the challenges of the system. Design thinking offers a structured approach that integrates creativity and innovation, yet its application in medical education is absent. Solution and implementation The compulsory MasterMinds Challenge course at Leiden University Medical Center utilizes design thinking principles to address real world healthcare challenges. Final-year medical students participated in a two-day program. The course encompassed empathizing with stakeholders, problem definition, ideation, prototyping, and refining solutions. Presentation skills were emphasized, culminating in a symposium where teams showcase their outcomes. Implementation of the MasterMinds Challenge course was successful with 33 sessions delivered to 1217 medical students. Challenges covered various healthcare topics, yielding creative yet practical outcomes. Students appreciate the real world healthcare challenge, team-based approach, and the applicability of design thinking principles. Challenge owners expressed satisfaction with students’ commitment, creativity, and empathizing abilities. Lessons learned and next steps To further enhance the MasterMinds Challenge course, a more longitudinal format is being designed, enabling greater autonomy and emphasizing the refining and implementation phases. The course can be extended to medical postgraduate professionals and interdisciplinary collaborations, fostering innovative ideas beyond current practices. By developing problem-solving skills, the MasterMinds Challenge course contributes to a future-proof medical education program and prepares students to meet the evolving needs of healthcare.

Incidence and centralization of chordoma in the Netherlands: A nationwide study between 1991 and 2020

IntroductionChordomas are rare malignant bone tumors arising in the axial skeleton, with an incidence of 0.3–0.88 per million inhabitants. We studied the annual incidence rate and centralization of treatment for chordoma in the Netherlands. MethodsWe retrieved pathology excerpts from the PALGA nationwide Dutch Pathology Registry between 1991 and 2019 for patients with a chordoma to calculate incidence rates. From pathology reports we extracted patient age at diagnosis, sex, year of diagnosis, localization of primary tumor, histologic chordoma subtype (conventional including chondroid, poorly differentiated or dedifferentiated), center of diagnosis (bone tumor referral center (BTC) or other hospital), and partial identification of the BTCs. ResultsA total of 420 individual chordoma patients were identified in the given time period. The incidence of chordoma increased from 0.593 per million inhabitants between 1991–1995 to 1.111 from 2015–2019 (P = 0.001). Median age at diagnosis was 63 years (range 1–95), 252 patients (60%) were male. The proportion of samples analyzed in a BTC either primarily or secondary, as a consultation, revision or referral, increased significantly from 29.3% to 84.4% (P < 0.001). Most primary and secondary samples were analyzed at the Leiden University Medical Center (LUMC, 54.4% and 57% respectively). ConclusionsThis study shows an increase in the standardized incidence of pathology proven chordoma in the Netherlands. We observed an increase in samples being analysed in the specialized BTCs as well, which is in line with current guidelines and will hopefully lead to more accurate diagnoses and optimal treatment plans for chordoma patients in specialized treatment centers.

Longitudinal Course of Long Finger Flexor Shortening in Males with Duchenne Muscular Dystrophy: A Retrospective Review1.

Shortening of the long finger flexors (Flexor Digitorum Profundus, FDPs) in Duchenne Muscular Dystrophy (DMD) causes reduced hand function. Until now, longitudinal studies on the natural course of the shortening of the FDPs are lacking, which impedes recommendations on timing and evaluation of preventive measures. To investigate the longitudinal course of the FDP length during different disease stages focusing on symmetry, timing, and decline of the FDP length. A retrospective, longitudinal multicenter study was conducted in the Radboud university medical center and the Leiden university medical center. The FDP outcome was measured using goniometry and gross motor function was assessed using the Brooke score. Longitudinal mixed model analyses were used to describe the course of the FDP outcome, and to investigate symmetry in both hands. Data on 534 visits of 197 males (age ranged 4-48 years) showed that in the ambulatory stages the FDP outcome was within a normal range. The mean decline in FDP outcome is 3.5 degrees per year, the biggest decline was seen in Brooke 5 (>15 degrees per year). In Brooke 4, 41% of the FDP outcome was < 40 degrees. No significant differences were found between right and left. This study supports the consideration of preventive measures to delay shortening of the FDPs in DMD patients transitioning to a Brooke scale of 4 or higher. Besides, natural history of FDP outcome has been established, which provides a base to evaluate (preventive) interventions.

Predicting response to iron supplementation in patients with active inflammatory bowel disease (PRIme): a randomised trial protocol

IntroductionIron deficiency anaemia (IDA) is the most common systemic manifestation of inflammatory bowel disease (IBD) that has detrimental effects on quality of life (QoL) and disease outcomes. Iron deficiency (ID),...

PRAME Expression: A Target for Cancer Immunotherapy and a Prognostic Factor in Uveal Melanoma.

Uveal melanoma (UM) is a rare disease with a high mortality, and new therapeutic options are being investigated. Preferentially Expressed Antigen in Melanoma (PRAME) is a cancer testis antigen, expressed in the testis, but also in cancers, including uveal melanoma. PRAME is considered a target for immune therapy in several cancers, and PRAME-specific T cell clones have been shown to kill UM cells. We studied the literature on PRAME expression in hematological and solid malignancies, including UM, and its role as a target for immunotherapy. The distribution of tumor features was compared between PRAME-high and PRAME-low UM in a 64-patient cohort from the Leiden University Medical Center (LUMC) and in the Cancer Genome Atlas (TCGA) cohort of 80 cases and differential gene expression analysis was performed in the LUMC cohort. PRAME is expressed in many malignancies, it is frequently associated with a negative prognosis, and can be the target of T cell receptor (TCR)-transduced T cells, a promising treatment option with high avidity and safety. In UM, PRAME is expressed in 26% to 45% of cases and is correlated with a worse prognosis. In the LUMC and the TCGA cohorts, high PRAME expression was associated with larger diameter, higher Tumor-Node-Metastasis (TNM) stage, more frequent gain of chromosome 8q, and an inflammatory phenotype. We confirm that PRAME is associated with poor prognosis in UM and has a strong connection with extra copies of 8q. We show that PRAME-specific immunotherapy in an adjuvant setting is promising in treatment of malignancies, including UM.

How to Use Costs in Value-Based Healthcare: Learning from Real-life Examples

BackgroundHealthcare organizations measure costs for business operations but do not routinely incorporate costs in decision-making on the value of care.AimProvide guidance on how to use costs in value-based healthcare (VBHC) delivery at different levels of the healthcare system.Setting and ParticipantsIntegrated practice units (IPUs) for diabetes mellitus (DM) and for acute myocardial infarction (AMI) at the Leiden University Medical Center and a collaboration of seven breast cancer IPUs of the Santeon group, all in the Netherlands.Program Description and EvaluationVBHC aims to optimize care delivery to the patient by understanding how costs relate to outcomes. At the level of shared decision-making between patient and clinician, yearly check-up consultations for DM type I were analyzed for patient-relevant costs. In benchmarking among providers, quantities of cost drivers for breast cancer care were assessed in scorecards. In continuous learning, cost-effectiveness analysis was compared with radar chart analysis to assess the value of telemonitoring in outpatient follow-up.DiscussionCosts vary among providers in healthcare, but also between provider and patient. The joint analysis of outcomes and costs using appropriate methods helps identify and optimize the aspects of care that drive desired outcomes and value.

Becker Muscular Dystrophy: Could Altering the Natural History of Decline Help Tackle Unmet Medical Need?

This symposium was held as part of the 28th International Annual Congress of the World Muscle Society (WMS), held in Charleston, South Carolina, USA. Speakers reviewed the natural history of Becker muscular dystrophy (Becker), outlined the top line, 12-month data from the ARCH open label study of investigational agent EDG-5506, and aimed to put those results into clinical context. Becker is a serious rare disease with significant physical, emotional, financial, and social impact on the affected individuals and their caregivers. Once function begins to decline, males affected by the progressive X-linked genetic disorder continue to irreversibly lose muscle, ultimately leading to the loss of ambulatory and cardiopulmonary function. After discussing the aetiology of the condition, Erik Niks, Paediatric and Adult Neurologist, Leiden University Medical Center (LUMC), the Netherlands, presented the findings of natural history studies. They showed that while the age at which decline begins varies, once it does start, patients tend to experience a consistent decline in function equivalent to around 1.2–1.3 North Star Ambulatory Assessment (NSAA) points each year. This finding, combined with data on using MRI as a biomarker of disease progression, provides an evidence-based framework for clinical trial design, he argued. Sam Collins, Vice President of clinical development, Edgewise Therapeutics, Boulder, Colorado, USA, then presented topline 12-month data from the ARCH study. It found that EDG-5506 was well tolerated, and, importantly, recorded the stabilisation of functional assessments, including the NSAA, with a trend towards improvement, as well as rapid, sustained, and significant decreases in biomarkers of progression, including those related to muscle damage. Putting the ARCH study data into context, Barry Byrne, Director of the Health Center for Advanced Therapeutics and Powell Gene Therapy Center, University of Florida (UF), Gainesville, USA, explained exactly how declining NSAA status translated into life-altering function loss. Stabilising function, or even reducing the speed of decline, was an important goal for patients, he said, adding that meeting it could help to address significant unmet medical need.

The effect of electro-anatomical mapping on the success rate and fluoroscopy time in supra-ventricular tachycardia ablation in children: single centre retrospective study

Abstract 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. Results: Outcomes of ablation of 373 electro-anatomical substrates were analysed. Acute success rate in the fluoro-group (n = 170) was 95.9% compared to 94.5% in the electro-anatomical mapping group (n = 181) (p = 0.539); recurrence rate was 6.1% in the fluoro-group and 6.4% in the electro-anatomical mapping group (p = 0.911) after a 12-months follow-up. Redo-ablations were performed in 12 cases in the fluoro-group and 10 cases in the electro-anatomical mapping group, with a success rate of 83.3% versus 80.0%, resulting in an overall success rate of 95.9% in the fluoro-group and 92.8% in the electro-anatomical mapping group (p = 0.216) after 12 months. Fluoroscopy time and dose area product decreased significantly from 16.00 ± 17.75 minutes (median ± interquartile range) to 2.00 ± 3.00 minutes (p = 0.000) and 210.5 µGym2 ± 249.3 to 32.9 µGym2 ± 78.6 (p = 0.000), respectively. In the fluoro-group, four complications occurred (2.0%) and in the electro-anatomical mapping group no complications occurred. Conclusion: These results demonstrate that ablations of supraventricular tachycardia substrates in children remain a highly effective and safe treatment after the introduction of electro-anatomical mapping as a standard of care, while significantly reducing fluoroscopy time and dose area product.