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Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome caused by mesenchymal tumors that secrete fibroblast growth factor 23 (FGF23). Patients present with progressive bone pain, muscle weakness, and fragility fractures. TIO is characterized by hypophosphatemia, excess renal phosphate excretion, and low/inappropriately normal 1,25-dihydroxyvitamin D (1,25(OH)2D) levels. Rarity and enigmatic clinical presentation of TIO contribute to limited awareness among the medical community. Accordingly, appropriate diagnostic tests may not be requested, leading to delayed diagnosis and poorer patient outcomes. We have developed a global guidance document to improve the knowledge of TIO in the medical community, enabling the recognition of patients with TIO and appropriate referral. We provide recommendations aiding diagnosis, referral, and treatment, helping promote a global standard of patient management. We reviewed the literature and conducted a three-round Delphi survey of TIO experts. Statements were drafted based on published evidence and expert opinions (≥70% consensus required for final recommendations). Serum phosphate should be measured in patients presenting with chronic muscle pain or weakness, fragility fractures, or bone pain. Physical examination should establish features of myopathy and identify masses that could be causative tumors. Priority laboratory evaluations should include urine/serum phosphate and creatinine to assess renal tubular reabsorption of phosphate and TmP/GFR, alkaline phosphatase, parathyroid hormone, 25-hydroxyvitamin D, 1,25(OH)2D, and FGF23. Patients with the clinical/biochemical suspicion of TIO should be referred to a specialist for diagnosis confirmation, and functional imaging should be used to localize causative tumor(s). Recommended treatment is tumor resection or, with unresectable/unidentifiable tumors, phosphate salts plus active vitamin D, or burosumab.

Funding Acknowledgements Type of funding sources: None. Background "Ablate and pace" strategy is a reasonable therapeutic option in refractory atrial fibrillation (AF) when rhythm or rate control cannot be achieved with catheter ablation or pharmacological therapy. Atrioventricular node ablation (AVNA) combined with conduction system pacing (CSP), including His-bundle pacing (HBP) and left bundle branch pacing (LBBP), are increasingly adopted, as they offer more physiological activation of the left ventricle compared to other pacing modalities. However, the incidence of conversion to sinus rhythm after "ablate and pace" strategy with CSP is not known. Purpose To determine the incidence of spontaneous conversion to sinus rhythm and its predicting factors in patients undergoing AVNA and CSP. Methods Refractory AF patients undergoing AVNA with CSP at our institution between June 2018 and May 2022 were prospectively included. Echocardiographic and clinical parameters including ECG were assessed at baseline and 6 months after the procedure. Results Sixty-three patients (male 41.3%, age 71±9 years, left ventricle ejection fraction (LVEF) 40% (IQR 20)) were included. Thirty-seven patients (58.7%) received HBP and 26 patients (41.3%) LBBP. During follow-up, spontaneous conversion to sinus rhythm (SR) was registered in 5 patients (8%); 3 in HBP group and 2 in LBBP group. Baseline characteristics of patients who converted to SR did not differ from non-sinus rhythm (NSR) patients except for left atrial volume index (LAVI), which was smaller in SR group (43 mL/m2 (IQR 6) vs. 60 mL/m2 (IQR 19); p Conclusion The results of our study show that spontaneous conversion to sinus rhythm after AVNA combined with CSP is not uncommon, especially in patients with smaller left atria. Patients who converted to SR showed superior symptomatic improvement compared to NSR patients. Larger studies are warranted to clarify the predicting variables of SR restoration in these patients, which should be considered for initial atrial pacing lead implantation (dual-chamber device) when "ablate and pace" strategy is adopted.

Funding Acknowledgements Type of funding sources: None. Introduction Catheter ablation for atrioventricular nodal reentry tachycardia (AVNRT) is usually performed with radiofrequency (RF) energy, which carries a risk of collateral conduction system injury. Cryoablation is a safer, but less effective alternative. Utilization of the three-dimensional electroanatomic mapping (3D EAM) system can potentially overcome some limitations of cryoablation and possibly improve procedural outcome. Purpose We retrospectively analyzed the feasibility, efficacy, and safety of cryoablation of AVNRT guided by 3D EAM system. Methods In this retrospective study, we analyzed consecutive patients who underwent cryoablation of AVNRT in our institution from April 2017 to May 2022. All procedures were performed with either magnetic-based or impedance-based system. A 3D model of the right atrium was created and important structures were annotated. Cryomapping was performed at the presumed slow pathway location, followed with cryoablation when appropriate. Location of cryoablation was annotated either with a dot superimposed from the distal electrode of the cryoablation catheter to the surface of the 3D model or the position of the cryoablation catheter was snapshotted. Intracardiac echocardiography (ICE) was utilized at the operator’s discretion. Procedural endpoint was AVNRT noninducibility, with up to one atrial echo beat allowed. Follow-up was performed with a visit to an outpatient clinic or with a telephone interview. Results The study included 122 consecutive patients (49/122 male; 33/122 pediatric patients, mean age 40.4 ± 22.1 years; mean BMI 25.0 ± 5.7 kg/m2). Altogether, 128 procedures were performed and 124 slow-fast AVNRT were diagnosed, 4 patients had slow-slow AVNRT. In six patients the procedure was repeated due to the recurrence of AVNRT. In two procedures, cryoablation was performed in the left atrium. Impedance-based 3D EAM system was used in 89.8% (115/128) of cases, while magnetic-based 3D EAM system was used in 10.2% (13/128) of cases. In 21.9% (28/128) of cases ICE was utilized. Median number of cryoablations was 3 (2 – 4) and median ablation time was 720 s (480 – 960 s). Cryomapping during ongoing AVNRT was possible in 52.3% (67/128) of cases, with mean time to termination of 13.4 ± 6.5 s. Mean procedural time was 80.9 ± 39.3 minutes. There were no major complications related to the procedure. Endpoint was achieved in 100% (128/128) of cases. Follow-up was completed in 96.7% (118/122) of cases, mean follow-up time was 484.7 ± 342.0 days. Arrythmia-free survival rate after first procedure was 88.1% (104/118). When all repeated procedures were included, the arrhythmia-free survival rate was 94.9% (112/118). Conclusion Cryoablation of AVNRT with utilization of the 3D EAM system is feasible, effective, and safe. Although, the success rate after first procedure is lower than expected, the procedure can be safely repeated to improve the outcome.

Funding Acknowledgements Type of funding sources: None. Introduction Transseptal puncture (TSP) is routinely performed to gain access into the left atrium for left-sided arrhythmias. Although fluoroscopy is mainly used for visualization of TSP, intracardiac echocardiography has been increasingly used to visualize the TSP. However, the available data to support routine use of ICE for visualization is scarce, particularly for pediatric patients and patients with cardiac implantable electronic devices (CIED). Purpose The purpose of this single-center retrospective study was to evaluate feasibility, efficacy, and safety of ICE guided TSP, also including pediatric patients and patients with CIED. Methods In this retrospective study, we analyzed consecutive patients who underwent ICE guided TSP from July 2014 to December 2021. When TSP was performed in patients with CIED, the device´s parameters were tested before and after the procedure. Adverse events (AE) were classified as those that were directly associated with the TSP and those who might be associated with the TSP. All AE either required an intervention, prolonged hospital stay, or had a negative impact on patient´s health. Results The study included 1360 consecutive patients (44.6% (607/1360) male; mean age 59.1 ± 15.6 years; mean BMI 28.1 ± 5.0 kg/m2), 4.3% (59/1360) of patients were pediatric (the youngest was 4 years old and weighed 17 kg) and 8.9% had a CIED (121/1360 – 56.2% (68/121) single chamber; 33.1% (40/121) dual chamber; 10.7% (13/121) resynchronization device). In majority, atrial fibrillation or atypical atrial flutter were the main indication for TSP (75.4%; 1062/1360), followed by ventricular tachycardia (9.4%; 128/1360), ventricular preexcitation (8.8%; 120/1360), and atrial tachycardia (3.5%; 47/1360). A total of 1839 punctures were performed (64.3% (875/1360) single TSP; 35.7% (485/1360) double TSP). Only in two patients (0.14%; 2/1360) the TSP was initially not possible. In one, it was later performed with radiofrequency needle. In total, there were 0.7% (13/1839) of AE. Two events (0.11%; 2/1839) were directly associated with the TSP. In one patient, a tamponade occurred immediately after a double TSP. In another patient with a dual chamber CIED, the ventricular lead was dislocated during the maneuvering of the TSP assembly. The other 11 events (0.6%; 11/1839 - 2 late tamponades and 9 pericardial effusions) could be associated with the TSP, however, they could also be associated with ablations or maneuvering of the catheters. In patients with CIED, there were 3 AE (2.1%; 3/144) – 1 AE was directly associated with the TSP (ventricular lead dislocation described above) and 2 AE which might be associated with the TSP (1 late tamponade and 1 pericardial effusion). There were no AE (0.0%; 0/60) in pediatric patients. Conclusion ICE guided TSP is an effective and safe method for obtaining left atrial access in adult and pediatric patients. Special care should be given to patients with CIED as lead dislocation is possible.

Quercetin (QtN) displays low systemic bioavailability caused by poor water solubility and instability. Consequently, it exerts limited anticancer action in vivo. One solution to increase the anticancer efficacy of QtN is the use of appropriate functionalized nanocarriers that preferentially target and deliver the drug to the tumor location. Herein, a direct advanced method was designed to develop water-soluble hyaluronic acid (HA)-QtN-conjugated silver nanoparticles (AgNPs). HA-QtN reduced silver nitrate (AgNO3) while acting as a stabilizing agent to produce AgNPs. Further, HA-QtN#AgNPs served as an anchor for folate/folic acid (FA) conjugated with polyethylene glycol (PEG). The resulting PEG-FA-HA-QtN#AgNPs (further abbreviated as PF/HA-QtN#AgNPs) were characterized both in vitro and ex vivo. Physical characterizations included UV-visible (UV-Vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), particle size (PS) and zeta potential (ZP) measurements, and biopharmaceutical evaluations. The biopharmaceutical evaluations included analyses of the cytotoxic effects on the HeLa and Caco-2 cancer cell lines using the MTT assay; cellular drug intake into cancer cells using flow cytometry and confocal microscopy; and blood compatibility using an automatic hematology analyzer, a diode array spectrophotometer, and an enzyme-linked immunosorbent assay (ELISA). The prepared hybrid delivery nanosystem was hemocompatible and more oncocytotoxic than the free, pure QtN. Therefore, PF/HA-QtN#AgNPs represent a smart nano-based drug delivery system (NDDS) and could be a promising oncotherapeutic option if the data are validated in vivo.

To evaluated obesity-related morbidity prevalence among overweight/obese children and adolescents in Saudi Arabia, adiposity indicators and insulin resistance as obesity-related morbidity predictors.We enrolled 318 overweight/obese children attending a Pediatric Endocrinology Clinic at King Abdulaziz University Hospital, Saudi Arabia, aged 2-20 years in this retrospective cross-sectional study from September 2019 to March 2021. All children had nutritional obesity, and their body mass index (BMI) standard deviation score was higher than one standard deviation score above the mean for their age and gender. Clinical adiposity indices including BMI, waist circumference (WC), waist-hip ratio (WHR), and bioimpedance analysis (BIA) of body composition were assessed. Biochemical testing of insulin resistance through homeostasis model assessment for insulin resistance and fasting insulin was performed, along with receiver operating curve analysis to obtain optimal cut-off points for obesity-related morbidity.Obesity related morbidity was found in 61.9%, whereas insulin resistance was detected among 64.7% of the patients. Body mass index standard deviation score, WC, BAI of body composition-derived body fat, homeostasis model assessment for insulin resistance, and fasting insulin are significant obesity-related morbidity predictors, and the cut-off points were established.Obesity-related morbidity is widely prevalent among obese children and insulin resistance is a key factor in its prediction. Clinical adiposity indices, given their accuracy and practicability, are important predictors of obesity-related morbidity.

Background The aim of this paper is to describe the utility of various recruitment modalities utilized in the Working to Increase Stability through Exercise (WISE) study. WISE is a pragmatic randomized trial that is testing the impact of a 3-year, multicomponent (strength, balance, aerobic) physical activity program led by trained volunteers or delivered via DVD on the rate of serious fall-related injuries among adults 65 and older with a past history of fragility fractures (e.g., vertebral, fall-related). The modified goal was to recruit 1130 participants over 2 years in three regions of Pennsylvania. Methods The at-risk population was identified primarily using letters mailed to patients of three health systems and those over 65 in each region, as well as using provider alerts in the health record, proactive recruitment phone calls, radio advertisements, and presentations at community meetings. Results Over 24 months of recruitment, 209,301 recruitment letters were mailed, resulting in 6818 telephone interviews. The two most productive recruitment methods were letters (72% of randomized participants) and the research registries at the University of Pittsburgh (11%). An average of 211 letters were required to be mailed for each participant enrolled. Of those interviewed, 2854 were ineligible, 2,825 declined to enroll and 1139 were enrolled and randomized. Most participants were female (84.4%), under age 75 (64.2%), and 50% took an osteoporosis medication. Not having a prior fragility fracture was the most common reason for not being eligible (87.5%). The most common reason provided for declining enrollment was not feeling healthy enough to participate (12.6%). Conclusions The WISE study achieved its overall recruitment goal. Bulk mailing was the most productive method for recruiting community-dwelling older adults at risk of serious fall-related injury into this long-term physical activity intervention trial, and electronic registries are important sources and should be considered.

Purpose/objective Teams are a critical part of modern health care, particularly in rehabilitation settings where multiple providers with different backgrounds and training work toward common goals. Rehabilitation psychologists have a legacy of providing leadership and influence for complex teams. Knowledge of interdisciplinary/transdisciplinary systems, leadership within those systems, and consultation across disciplines are foundational competencies for rehabilitation psychologists. Research Method/Design: This paper summarizes the different roles rehabilitation psychologists serve on health care teams and identifies opportunities for improved effectiveness. An overview of leadership theory over time is provided. Results Even when psychologists are not formal team leaders, opportunities exist to leverage team member strengths and encourage the development of leader behaviors across the team in support of good patient care. Conclusions/implications Drawing from the management and organizational development literature, evidence-based suggestions are provided for rehabilitation psychologists seeking to foster healthy team dynamics within and among health care teams. The authors encourage rehabilitation psychologists to use their unique training to facilitate shared leadership on teams that foster and encourage a climate of trust, psychological safety, healthy and productive conflict, along with strong communication practices. These issues became even more salient as teams transitioned to virtual platforms during the pandemic and continue to adapt to hybrid work environments. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder that represents a range of aberrant behaviour symptoms such as repetitive behaviours and defects in social communication. The prevalence of ASD has been increasing worldwide and many studies have reported that both genetic and epigenetic factors play an important role in the etiology of this disorder. The aim of this study was to investigate the implementation of DNA methylation and Copy number variation (CNV) in the diagnosis of ASD.This study was carried out on 14 Saudi autistic children and four of their healthy siblings. Comparative genomic hybridization array was used to identify CNV in chromosome 14 and MethyLight qPCR was used to estimate levels of DNA methylation.The results identified CNVs in six cytobands in chromosome 14 for 13 out of 14 autistic samples: 14q11.1-q11.2, 14q11.2, 14q12, 14q21.1, 14q32.2, and 14q32.33. However, some of these cytobands were also found in normal samples with different sizes. Interestingly, chromosomal abnormalities in 14q11.1-q11.2 was only found in ASD samples. The result also showed an increase in methylation ratio of ASD samples in those CNV regions compared with their siblings.The findings suggest that CNV in 14q11.1-q11.2 might be a potential target in ASD diagnosis and further work is required to detect which biological pathways are affected.

Background: Endoscopic sinus surgery is mostly conducted for the removal of the inflammatory as well as infectious diseases of sinus and malignant or benign nasal, paranasal & nasopharyngeal pathologies. The various surgical approaches that have been used range from transpalatine to a lateral rhinotomy and to mid-facial degloving. Aim: To determine the outcome of mid-facial degloving approach facilitated with endoscope for nasal, paranasal and nasopharyngeal pathologies. Methods: Forty five patients that fulfilled the inclusion criteria were enrolled in the study. All the patients were then underwent surgery by the researcher along with a surgical team under general anesthesia by using Mid-facial degloving approach. The patients were followed - up on 3 & 6 months after the surgery and underwent clinical examination and endoscopic nasal examination to assess the complications, cosmetic outcome and recurrence after the procedure during the follow-up period. Data was entered & analyzed using SPSS v. 23. Results: Mean age of the patients in the sample was 25.47±10.52 years. There were 39(86.7%) male patients and 6(13.3%) female patients. Cosmetic outcome was excellent in 31(68.9%) cases, satisfactory in 12(26.7%) while 2(4.4%) variable comments about the cosmetic effects of the procedure. Bleeding was most common complication 3(6.7%), however recurrence occurred in 3(6.7%) cases. Conclusion: It is concluded that mid-facial degloving approach is a highly successful method for removal of nasal, paranasal or nasopharyngeal pathologies. Key words: Mid-facial degloving, endoscope, nasal, paranasal, nasopharyngeal, pathologies

The potential role of DNA methylation pattern in autism has been provided by revealing the differences in methylation level of multiple genes which are significantly associated with their expression and implicated in ASD pathogenesis. RASA3 is a member of GTPase-activating proteins, RASA3 is highly expressed in brain tissues and can be deregulated by different epigenetic mechanisms. Many studies reported that differentially expressed RASA3 is correlated with its aberrant methylation. Accordingly, this has been suggested that deferentially expression of RASA3 may be correlated with its methylation levels which could play a role in ASD which brought our attention to identify differentially-expressed genes that could be associated with their methylation level of ASD in Saudi population, by performing comparative gene expression of RASA3 then investigate its relation to methylation level. This study was conducted on 18 Saudi autistic children as well as their healthy-control siblings. Relative expression of a candidate gene (RASA3) was measured using RT-qPCR. Furthermore, MethyLight assay was performed to estimate methylation level and evaluate its impact on RASA3 expression. Interestingly, RASA3 expression has found to be dysregulated in ASD cases. In contrast, MethyLight assay result showed no differences in the methylation patterns among ASD cases in the candidate region. However, it remains an open question whether these dysregulations of RASA3 expression could be a biomarker for early screening/detection of some cases which may also suggest a role for RasGAPs in autistic brain function.

The development of coronavirus disease 2019 (COVID‐19) vaccines has proceeded at an unprecedented pace, with numerous trials conducted simultaneously across the world as a result of massive technological and financial resource expenditures. With multiple vaccines having now received regulatory approval, public health efforts to promote widespread vaccine dissemination are currently underway. There has been particular emphasis placed on vaccination of older populations, the age group in which COVID‐19 infection has been most lethal. However, such widespread vaccination approaches have necessarily raised important questions related to potential interactions with underlying diseases and concomitant treatments among persons to be vaccinated. Osteoporosis is a chronic condition marked by reduced bone strength and an associated increased risk for fracture that generally requires sustained medical intervention(s). Osteoporosis is neither associated with a higher risk of COVID‐19 infection nor by more pronounced disease severity following infection, such that individuals with osteoporosis need not be more highly prioritized for COVID‐19 vaccination. Osteoporosis therapies do not interfere with the efficacy or side effect profiles of COVID‐19 vaccines and should not be stopped or indefinitely delayed because of vaccination. Depending on the specific drug profile within an anti‐osteoporosis medication category, minor adjustments to the timing of drug administration may be considered with respect to the patient's COVID‐19 vaccination schedule. Herein we provide practical recommendations for the care of patients requiring treatment for osteoporosis in the setting of COVID‐19 vaccination. © 2021 American Society for Bone and Mineral Research (ASBMR).

Passing clouds and wind gusts can create unacceptable rapid voltage/power variations in power networks. Simulation results using a real Australian distribution feeder with real load demand and PV output profile show that with a high penetration of PV the voltage variations can increase beyond the allowable limit given by the standards. Similarly, wind gusts can create wind power output variations. This paper addresses the rapid voltage/power variations caused by solar or wind power outputs and presents a control strategy using the energy buffer in energy storage for their impact mitigation. By controlling the discharging/charging operation of the energy storage based on the available energy buffer in the storage unit, not only the rate of power output variations can be maintained at the desired level, but also the voltage variations can be controlled within acceptable limits. An experimental setup, consisting of a PV emulator, inverter, and grid simulator, demonstrates the potential threat of unacceptable voltage variations. The proposed mitigation strategy using energy buffer in the storage for smoothing the power outputs of solar/wind is tested and validated through simulation. Simulation results show that with the proposed control, the fast variations of the voltage/power variations instigated by solar/wind can be maintained within the acceptable limits.

Funding Acknowledgements Type of funding sources: None. Background Atrioventricular node ablation (AVNA) with biventricular (BiV) pacing is an established treatment option for heart failure (HF) patients with drug refractory atrial fibrillation (AF) (1). However, compared to conduction system pacing (CSP) modalities, including His bundle pacing (HBP) and left bundle branch pacing (LBBP), BiV pacing delivers non-physiological ventricular activation (2). Purpose To compare clinical outcomes of BiV pacing and both CSP modalities in HF patients with symptomatic AF who underwent AVNA. Methods Consecutive AF patients with LV ejection fraction (LVEF Results Fifty-five patients (male 43.6%, age 71 years (IQR 10), LVEF 39% (IQR 14)) were included. Thirteen patients (23.6%) received BiV pacing, 30 patients (54.5%) HBP and 12 patients (21.8%) LBBP. All groups had similar baseline characteristics, acute success rate and adverse events. Post-procedural QRS duration was significantly shorter (p Conclusion Conduction system pacing modalities showed superior symptomatic and echocardiographic improvement compared to BiV pacing after AVNA. While LBBP offered lower and more stable pacing parameters, there were no differences in clinical outcomes and echocardiographic remodelling when compared to HBP.

Funding Acknowledgements Type of funding sources: None. Introduction Catheter ablation (CA) of supraventricular tachycardias (SVTs) in pediatric patients is conventionally performed with the aid of X-ray fluoroscopy. Usage of the three-dimensional (3D) electro-anatomical mapping (EAM) system and the intracardiac echocardiography (ICE) enables zero-fluorscopy ablation, eliminating the harmful effects of the radiation (1-3). Purpose We retrospectively analyzed the feasibility, effectiveness and safety of zero-fluoroscopy radiofrequency and cryoablation of various types of SVTs in pediatric patients. Methods In this retrospective study, we analyzed consecutive pediatric patients who underwent CA procedure due to SVT in our institution from April 2014 to October 2021. All procedures were performed completely without the use of fluoroscopy. A 3D EAM system and ICE were used as the principal modes of catheter visualisation. Left-sided procedures were done with ICE guided transseptal approach. Radiofrequency was the principal energy source, while cryoablation was used for arrhythmia substrates in the proximity of the conduction system. Results The study included 174 consecutive patients (69/174 (66%) female; 12.5 ± 3.9 years; 19.2 ± 3.6 kg/m2). Altogether 176 SVTs were diagnosed and treated. Atrio-ventricular nodal reentry tachycardia (AVNRT) was diagnosed in 45% of cases (80/176), atrio-ventricular reentry tachycardia (AVRT) in 47% (82/176), focal atrial tachycardia (AT) in 7% (13/176), typical atrial flutter (AFL) was treated in only one patient, while 2 patients had multiple arrhythmias (AVNRT and AVRT). In total, 202 procedures were performed. Radiofrequency ablation was performed in 76% (154/202), cryoablation in 20% (40/202) and both in 4% (8/202) of procedures. The acute procedural success rate was 96% (195/202). Procedural success rate was 99% (79/80) for AVNRT, 94% (77/82) for AVRT, 92% (12/13) for AT, and 100% (1/1) for AFL, respectively. There were no major complications in our study group. Follow-up was complete in 99% (172/174) of patients. During the follow-up period of a median of 316 days (181 - 747), 98% of patients were arrhythmia free. On average, 1.16 procedures per patient were performed with the long-term success rate of 99% (79/80), 98% (80/82), 100% (13/13) and 100% (1) for AVNRT, AVRT, AT, and AFL, respectively. Conclusion Zero-fluoroscopy CA of various types of SVTs in pediatric population is a feasible, effective, and safe treatment option.

Funding Acknowledgements Type of funding sources: None. Introduction Traditionally, X-ray fluoroscopy is used during catheter ablation procedures. The utilisation of ionising radiation carries non-negligible stochastic and deterministic risks to the health of both the patient and the professional staff. These effects are cumulative and behave in a linear no-threshold manner and, as such, are especially important in paediatric populations (1). The importance of reducing ionising radiation exposure has been recognised by the American College of Cardiology, which recommends the ALARA (as low as reasonably achievable) principle in all interventional laboratories (2). In recent years, advances in three-dimensional electroanatomical mapping systems and their utilisation have enabled the near-zero and zero-fluoroscopy approaches to be studied (3). Purpose The aim of this study was to evaluate the safety and efficacy of zero-fluoroscopy catheter ablation for supraventricular tachycardias (SVT). Methods 584 consecutive patients referred to our institution for catheter ablation of SVT were analysed. Patients were categorised into two groups; zero-fluoroscopy (ZF) group and conventional fluoroscopy (CF) group. Patient characteristics, procedural information, and follow-up data were compared. Results The ZF group had a higher proportion of paediatric patients (42.2% vs 0.0 %; p < 0.001), resulting in a younger age (30.9 ± 20.3 years vs 52.7 ± 16.5 years; p < 0.001) and lower BMI (22.8 ± 5.7 kg/m2 vs 27.0 ± 5.4 kg/m2; p < 0.001). Procedure time was shorter in the ZF group (94.2 ± 50.4 min vs 104.0 ± 54.0 min; p = 0.002). There were no major complications and the rate of minor complications did not differ between groups (0.0% vs 0.4%; p = 0.304). Acute procedural success as well as the long-term success rate when only the index procedure was considered did not differ between groups (92.5% vs 95.4%; p = 0.155; 87.1% vs 89.2%; p = 0.422). When repeated procedures were included, the long-term success rate was higher in the ZF group (98.3% vs 93.5%; p = 0.004). The difference can be partially explained by the operators’ preferences. Conclusion The safety and efficacy of ZF procedures in adult and paediatric populations are comparable to that of CF procedures.

Funding Acknowledgements Type of funding sources: None. Background Paediatric patients with conduction abnormalities are generally exposed to life-long dyssynchronous pacing from a very early age. Thus, preservation of cardiac function during chronic ventricular pacing is important. Conduction system pacing (CSP) with His bundle pacing (HBP) or left bundle branch pacing (LBBP) is an alternative method to standard right ventricular (RV) pacing that may preserve physiological ventricular activation and avoid potential pacing-induced cardiomyopathy (1). However, data on feasibility and safety of various CSP approaches in paediatric patients with or without congenital heart disease (CHD) is scarce and mainly relies on case studies (2-4). Purpose To assess feasibility and outcomes of different CSP techniques in paediatric patients. Methods Consecutive paediatric patients in whom CSP was attempted in our centre between November 2019 and December 2021 were analysed. Acute implant success rate, complications, fluoroscopy times, and CSP pacing parameters during follow-up were assessed. To reduce radiation exposure, minimal fluoroscopy technique with three-dimensional (3D) electro-anatomical mapping (EAM) was also used in some cases. Geometry of right atrium and RV, along with mapping of His signal for HBP and potential LBBP sites in the RV septum were created using a decapolar catheter from the right femoral vein. Once relevant anatomy was obtained, HBP or LBBP was attempted using commercially available CSP tools. The pacing lead tip was visualised using the 3D EAM system. Transient fluoroscopy was used only for perpendicular placement of the sheath to the RV septum during LBBP, sheath removal, lead loop assessment to allow linear growth, and atrial lead placement. Results Six patients (100% female, age 9.3 ± 3.9 years, weight 41.8 ± 22.9 kg, baseline QRS 111.5 ± 6.3ms, CHD 50%, previous device 33%) with congenital complete AV block received CSP. One patient received HBP and 5 LBBP. The procedure was acutely successful in all patients (100%), pacing thresholds were low (0.56 ± 0.18V at 0.5ms) and there were no perioperative complications. During mean follow-up of 11.8 ± 7.8 months pacing parameters remained stable. However, significant rise of the pacing threshold (> 2.5V) was registered in the HBP patient, in whom lead revision was performed. Three-dimensional EAM was utilised in 3 patients (1 HBP, 2 LBBP). The use of minimal fluoroscopy technique with 3D EAM reduced fluoroscopy time (4.0, 3.2, 4.5 min vs. 9.5, 11.0, 8.0 min) without increasing procedural time (80, 70, 50 min vs. 110, 60, 75 min) compared to standard fluoroscopy technique. Conclusion Conduction system pacing is feasible and safe in paediatric patients with or without CHD. Additional utilisation of 3D EAM could reduce radiation exposure, without increasing procedural time. Future long-term studies should be considered to provide the ground for wider clinical adoption of CSP in paediatric population.

Funding Acknowledgements Type of funding sources: None. Background In patients with persistent atrial fibrillation (PeAF) and heart failure with reduced ejection fraction (HFrEF) current guidelines recommend treatment of AF with catheter ablation (CA) (1). Recurrence of either AF or atrial flutter, often requiring additional procedures, are not uncommon, thus optimal long-term treatment of these patients is still unknown. Recently conduction system pacing (CSP), with more physiological ventricular activation, has made the ‘’pace and ablate’’ strategy an attractive alternative for the treatment of PeAF refractory to medical therapy (2). Purpose Long term data comparing CA with conduction system pacing and AV node ablation (CSP/AVNa) for treatment of patients with PeAF and HFrEF is lacking. Hence, we sought to compare clinical outcomes of both treatment modalities. Methods In a retrospective study consecutive patients under 75 years of age, with PeAF and left ventricular ejection fraction (LVEF) less than 50%, treated with CSP/AVNa from 2018 to 2021 in UMC Ljubljana were included. A control patient treated with CA for PeAF matched in age, sex and LVEF was assigned for each included CPS/AVNa patient. Both groups were compared for procedure-related characteristics, echocardiographic parameters, hospitalisations for heart failure and all-cause mortality. Results Among 771 patients referred for interventional treatment of AF, 23 patients treated with CSP/AVNa were included and compared with 23 CA matched controls. The general characteristics of both groups are summarised in Table 1. The mean follow-up was 20 ± 10 and 21 ± 8 months for CPS/AVNa and CA group, respectively (p=0.76). In CPS/AVNa group 83% received his bundle pacing and 17% left bundle branch area pacing. A selective CSP was achieved in 43% of CSP/AVNa patients. In addition to pulmonary vein isolation, additional ablation lines were performed in 35% of patients in the CA group. Significant improvement in LVEF was observed in both groups, 12% ± 11% (p Conclusion In patients with PeAF and HFrEF, CSP/AVNa treatment strategy seems to derive similar clinical outcomes compared to CA approach. Larger prospective randomised data are needed to further confirm these initial findings and determine optimal long-term treatment strategy for this group of patients.

Tumor-induced osteomalacia (TIO) is a rare and largely underdiagnosed paraneoplastic condition. Previous reviews often reported incomplete data on clinical aspects, diagnosis or prognosis. The aim of this study was to present a systematic clinical review of all published cases of TIO. A search was conducted in Pubmed, Embase, Web of Science from inception until April 23rd, 2020. We selected case reports and case series of patients diagnosed with TIO, with information on tumor localization and serum phosphate concentration. Two reviewers independently extracted data on biochemical and clinical characteristics including bone involvement, tumor localization and treatment. 468 articles with 895 unique TIO cases were included. Median age was 46 years (range 9 months–90 years) and 58.3% were males. Hypophosphatemia and inappropriately low or normal 1,25-dihydroxyvitamin D levels, characteristic for TIO, were present in 98% of cases. Median tumor size was 2.7 cm (range 0.5 to 25.0 cm). Serum fibroblast growth factor 23 was related to tumor size (r = 0.344, P n = 61/99) and a fracture was reported in at least 39% of all cases (n = 346/895). Diagnostic delay was longer than 2 years in more than 80% of cases. 10% were reported to be malignant at histology. In conclusion, TIO is a debilitating disease characterized by a long diagnostic delay leading to metabolic disturbances and skeletal impairment. Increasing awareness of TIO should decrease its diagnostic delay and the clinical consequences.