Search

Left ventricular assist device (LVAD) utilization is increasing in pediatrics. These patients are often complex and may require treatment of AV block. Leadless pacing has been associated with a lower risk of device-related adverse events, but there are no reports of a leadless pacemaker implant in a pediatric patient with LVAD support. This report describes the use of a leadless pacemaker implantation in a 17-year-old patient with dilated cardiomyopathy and continuous flow LVAD support which facilitated transition to outpatient care., Competing Interests: Declarations. Conflicts of interest: Author John Seger, MD has a consulting relationship with Medtronic related to training on cardiac rhythm products.. He did participate in the implant procedure, but did not participate in the decision of what type of device was going to be utilized in this particular patient. All other authors have no disclosures., (© 2025. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Infants with complete heart block (CHB) require epicardial pacemaker (PM) insertion. Prior studies described epicardial pacing outcomes in infants and children, although they were limited by small or heterogeneous populations., Objective: This study aimed to explore patient- and procedure-level associations with device complications in infants with CHB who received a permanent PM., Methods: This was a multicenter, retrospective cohort study including infants receiving an epicardial PM between 2000 and 2021 for CHB. The primary outcome was time to device-related adverse event: lead failure requiring revision; pocket infection; exit block requiring increased pacing output; or lead-related coronary artery compression. Time-to-event analysis was performed by the Kaplan-Meier method with a multivariable Cox proportional hazards model., Results: There were 174 infants who received an epicardial PM (282 bipolar, 39 unipolar leads) for CHB. Median age and weight at PM were 93.5 days and 4.5 kg, respectively. Pacing indication was postoperative CHB in 63% and congenital CHB in 37%. The median follow-up was 2.1 years. The primary outcome occurred in 26 infants at a median time to event of 0.6 year. Age ≤90 days at PM implantation was the most significant risk factor for a device-related adverse event (hazard ratio, 7.02; P < .001), primarily driven by pocket infections. Lead failure occurred in 3% of leads with a 5- and 10-year freedom from failure of 93% and 83%, respectively., Conclusion: Device complications affect 15% of infants receiving a permanent PM for heart block. Age ≤90 days at PM implantation is especially associated with infectious complications. Epicardial lead durability appears similar to previously reported pediatric experiences., Competing Interests: Disclosures The authors have no conflicts of interest to disclose., (Copyright © 2024 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Heart rate variability (HRV) is a noninvasive indicator of the health of neurocardiac interactions of the autonomic nervous system. In adults, decreased HRV correlates with increased cardiovascular mortality. However, the relationship between HRV and outcomes in children with acute decompensated heart failure (ADHF) has not been described. Patients < 21 years old hospitalized with ADHF from 2013 to 2019 were included (N = 79). Primary outcome was defined as death, heart transplant, or mechanical circulatory support (MCS). The median standard deviation of the R-to-R interval in 5-min intervals (SDNN) was calculated from telemetry data obtained across the first 24 h of admission. Patients who met the primary outcome had significantly lower median SDNN (13.8 [7.8, 29.1]) compared to those who did not (24.6 [15.3, 84.4]; p = 0.004). A median SDNN of 20 ms resulted in a sensitivity of 68% and specificity of 69%. Median SDNN < 20 ms represented decreased freedom from primary outcome (p = 0.043) and a hazard ratio of 2.2 in multivariate analysis (p = 0.016). Pediatric patients with ADHF who died, underwent heart transplant, or required MCS had significantly decreased HRV at presentation compared to those that did not. This supports HRV as a noninvasive tool to improve prognostication in children in ADHF., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Event monitors are being increasingly used in pediatric and adult congenital heart disease (ACHD) patients for arrhythmia evaluation. Data on their diagnostic yield are limited., Objectives: To evaluate the diagnostic yield of event monitors, patient characteristics associated with critical events, and clinical response to events., Methods: We retrospectively assessed event monitors prescribed to patients at our institution's Heart Center from 2017 to 2020. Thirty-day event monitor tracings were reviewed by an electrophysiologist (EP) to identify critical events defined as supraventricular tachycardia (SVT, re-entrant, atrial tachycardia, atrial flutter, and atrial fibrillation), ventricular tachycardia (VT), atrioventricular block, and pauses greater than 3 s. Patient characteristics and treatment data were collected. Characteristics associated with events were assessed using multivariable logistic regression. Trends in monitor prescription over time, diagnostic yield, and clinical response to events were analyzed., Results: 204/2330 (8.8%) event monitors had EP-confirmed critical events. Critical events included SVT (51.5%), VT (38.5%), atrioventricular block (4%), and pauses (6%). 129/198 (65%) patients with critical events underwent treatment. Event monitoring usage increased by 52% between 2017 and 2020 (p < 0.0001). Complex CHD (OR 2.1, 95% CI 1.3-3.4, p = 0.004), cardiomyopathy (OR 2.9, 95% CI 1.5-4.8, p < 0.001), and EP-ordered monitors (OR 1.6, 95% CI 1.2-2.1, p = 0.001) were more highly associated with critical events., Conclusion: Event monitor use is common, and critical events were captured in 8.8% of patients. The majority of patients with critical events underwent treatment. Factors associated with critical events include EPs as ordering providers, complex CHD, and cardiomyopathy., (© 2024 Wiley Periodicals LLC.)

Background: DSP cardiomyopathy is a distinct subset of arrhythmogenic cardiomyopathy, reported primarily in adults, that has predominantly left ventricular involvement and features of myocarditis. Clinical characteristics, risk stratification, and management of pediatric patients with DSP variants are not well known. We sought to identify phenotypic features and prognosis of pediatric patients with DSP pathogenic or likely pathogenic variants., Methods: Multicenter, retrospective study of patients <21 years of age with DSP variants from 6 tertiary pediatric hospitals., Results: Thirty-four patients, including 10 probands with clinical disease and 24 genotype-positive phenotype-negative patients, were included in the study. The majority of probands were initially diagnosed with myocarditis (50%) and had biventricular (60%) or left ventricular predominant (40%) disease. Chest pain was the most common symptom at presentation (30%), and all had troponin elevation. Probands with homozygous or compound heterozygous DSP variants were likely to present at an early age (<13 years) with symptoms of heart failure, severe biventricular involvement, and dermatologic abnormalities. Low-voltage QRS was the most prominent ECG abnormality. Of those who underwent implantable cardioverter defibrillator implantation, 50% received appropriate implantable cardioverter defibrillator therapy and were found to have significant biventricular involvement in addition to severe left ventricular dysfunction with an ejection fraction <35%., Conclusions: DSP cardiomyopathy in children and adolescents has varied phenotypic manifestations based on age and genotype and often can be diagnosed as myocarditis. Severe left ventricular dysfunction and biventricular involvement may be associated with a higher likelihood of malignant ventricular tachyarrhythmia., Competing Interests: None.

Background: Dexmedetomidine, an alpha 2 agonist, has emerged as a desirable sedative agent in the pediatric intensive care unit due to its minimal effect on respiratory status and reduction in delirium. Bradycardia and hypotension are common side effects, however there are emerging reports of more serious cardiovascular events, including sinus arrest and asystole. These case reports have been attributed to high vagal tone or underlying cardiac conduction dysfunction. Objectives: To describe the development of sinus arrest during sedation with dexmedetomidine in a patient without clinical features of high vagal tone, underlying cardiac conduction dysfunction, or intervening episodes of bradycardia. Case Presentation: An 11 month-old patient requiring sedation during mechanical ventilation for acute respiratory failure secondary to Adenovirus. To facilitate sedation, a dexmedetomidine infusion was initiated at .5 mcg/kg/hr and increased to maximum 1 mcg/kg/hr. Within 8 hours of initiating therapy, the patient had three episodes of sinus arrest. There was no intervening bradycardia between episodes and no further episodes occurred following discontinuation of dexmedetomidine. The patient did not have any clinical features associated with high vagal tone or underlying cardiac conduction dysfunction. Conclusions: As result of these findings, understanding risk factors for bradycardia, or more serious hemodynamic instability with dexmedetomidine infusions, is important to help identify high risk patients and weigh the associated risks and benefits of its administration., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

This article reviews various opportunities to translate established and novel tools and techniques used in adult electrophysiology to pediatrics and the adult congenital heart disease population. There is a specific focus on preoperative management of special population, implantation techniques, and postoperative programming of devices., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: 1p36 deletion syndrome can predispose to pediatric-onset cardiomyopathy. Deletion breakpoints are variable and may delete the transcription factor PRDM16 . Early studies suggest that deletion of PRDM16 may underlie cardiomyopathy in patients with 1p36 deletion; however, the prognostic impact of PRDM16 loss is unknown., Methods: This retrospective cohort included subjects with 1p36 deletion syndrome from 4 hospitals. Prevalence of cardiomyopathy and freedom from death, cardiac transplantation, or ventricular assist device were analyzed. A systematic review cohort was derived for further analysis. A cardiac-specific Prdm16 knockout mouse ( Prdm16 conditional knockout) was generated. Echocardiography was performed at 4 and 6 to 7 months. Histology staining and qPCR were performed at 7 months to assess fibrosis., Results: The retrospective cohort included 71 patients. Among individuals with PRDM16 deleted, 34.5% developed cardiomyopathy versus 7.7% of individuals with PRDM16 not deleted ( P =0.1). In the combined retrospective and systematic review cohort (n=134), PRDM16 deletion-associated cardiomyopathy risk was recapitulated and significant (29.1% versus 10.8%, P =0.03). PRDM16 deletion was associated with increased risk of death, cardiac transplant, or ventricular assist device ( P =0.04). Among those PRDM16 deleted, 34.5% of females developed cardiomyopathy versus 16.7% of their male counterparts ( P =0.2). We find sex-specific differences in the incidence and the severity of contractile dysfunction and fibrosis in female Prdm16 conditional knockout mice. Further, female Prdm16 conditional knockout mice demonstrate significantly elevated risk of mortality ( P =0.0003)., Conclusions: PRDM16 deletion is associated with a significantly increased risk of cardiomyopathy and cardiac mortality. Prdm16 conditional knockout mice develop cardiomyopathy in a sex-biased way. Patients with PRDM16 deletion should be assessed for cardiac disease., Competing Interests: Disclosures The Department of Molecular and Human Genetics at Baylor College of Medicine receives revenue from clinical genetic testing performed at Baylor Genetics Laboratories.

Objectives: To investigate beliefs and factors associated with padded headgear (HG) use in junior (<13 years) and youth (≥13 years) Australian football., Design: Online survey., Setting: Junior and youth athletes in Australia., Participants: Australian football players aged U8 to U18., Assessment of Variables: Survey questions regarding demographics, HG use, concussion history, beliefs about HG, and risk-taking propensity., Main Outcome Measures: Rates of padded HG use, and beliefs associated with HG use., Results: A total of 735 players (including 190, 25.9% female) representing 206 clubs participated. Headgear was worn by 315 players (42.9%; 95% CI: 39.3-46.4). Most (59.5%) HG users wore it for games only and wore it voluntarily (59.7%), as opposed to being mandated to do so. Junior players were more likely than youth players to agree to feeling safer ( P < 0.001) and being able to play harder while wearing HG ( P < 0.001). Median responses were "disagree" on preferring to risk an injury than wear HG, and on experienced players not needing to wear HG. Beliefs did not differ between males and females. Headgear use was associated with players belonging to a club where HG was mandated for other age groups (OR 16.10; 95% CI: 7.71-33.62, P < 0.001), youth players (OR 2.79; 95% CI: 1.93-3.93, P < 0.001), and female players (OR 1.57; 95% CI: 1.07-2.30, P = 0.019)., Conclusions: Club HG culture, older age and being female were prominent variables associated with voluntary HG use. Players reported believing that HG offers protection. The rate of voluntary and mandated HG use identified is at odds with current scientific evidence that does not support HG as effective concussion prevention., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: TANGO2 deficiency disorder (TDD), an autosomal recessive disease first reported in 2016, is characterized by neurodevelopmental delay, seizures, intermittent ataxia, hypothyroidism, and life-threatening metabolic and cardiac crises. The purpose of this study was to define the natural history of TDD., Methods: Data were collected from an ongoing natural history study of patients with TDD enrolled between February 2019 and May 2022. Data were obtained through phone or video based parent interviews and medical record review., Results: Data were collected from 73 patients (59% male) from 57 unrelated families living in 16 different countries. The median age of participants at the time of data collection was 9.0 years (interquartile range = 5.3-15.9 years, range = fetal to 31.8 years). A total of 24 different TANGO2 alleles were observed. Patients showed normal development in early infancy, with progressive delay in developmental milestones thereafter. Symptoms included ataxia, dystonia, and speech difficulties, typically starting between the ages of 1 to 3 years. A total of 46/71 (65%) patients suffered metabolic crises, and of those, 30 (65%) developed cardiac crises. Metabolic crises were significantly decreased after the initiation of B-complex or multivitamin supplementation., Conclusion: We provide the most comprehensive review of natural history of TDD and important observational data suggesting that B-complex or multivitamins may prevent metabolic crises., Competing Interests: Conflict of Interest The Department of Molecular and Human Genetics at Baylor College of Medicine derives revenue from clinical laboratory testing conducted at Baylor Genetics. S.A.M. serves as Scientific Advisor and consultant for Aytu BioPharma, Inc for the AR101 Enzastaurin Clinical Trial. All other authors declare no conflicts of interest., (Copyright © 2022 American College of Medical Genetics and Genomics. Published by Elsevier Inc. All rights reserved.)

Background: Transcatheter Leadless Pacemakers (TLP) are a safe and effective option for adults with pacing indications. These devices may be an alternative in pediatric patients and patients with congenital heart disease for whom repeated sternotomies, thoracotomies, or transvenous systems are unfavorable. However, exemption of children from clinical trials has created uncertainty over the indications, efficacy, and safety of TLP in the pediatric population. The objectives of this study are to evaluate clinical indications, procedural characteristics, electrical performance, and outcomes of TLP implantation in children., Methods: Retrospective data were collected from patients enrolled in the Pediatric and Congenital Electrophysiology Society TLP registry involving 15 centers. Patients ≤21 years of age who underwent Micra (Medtronic Inc, Minneapolis, MN) TLP implantation and had follow-up of ≥1 week were included in the study., Results: The device was successfully implanted in 62 of 63 registry patients (98%) at a mean age of 15±4.1 years and included 20 (32%) patients with congenital heart disease. The mean body weight at TLP implantation was 55±19 kg and included 8 patients ≤8 years of age and ≤30 kg in weight. TLP was implanted by femoral (n=55, 87%) and internal jugular (n=8, 12.6%) venous approaches. During a mean follow-up period of 9.5±5.3 months, there were 10 (16%) complications including one cardiac perforation/pericardial effusion, one nonocclusive femoral venous thrombus, and one retrieval and replacement of TLP due to high thresholds. There were no deaths, TLP infections, or device embolizations. Electrical parameters, including capture thresholds, R wave sensing, and pacing impedances, remained stable., Conclusions: Initial results from the Pediatric and Congenital Electrophysiology Society TLP registry demonstrated a high level of successful Micra device implants via femoral and internal venous jugular approaches with stable electrical parameters and infrequent major complications. Long-term prospective data are needed to confirm the reproducibility of these initial findings.

Background: Genetic defects in the RAS/mitogen-activated protein kinase pathway are an important cause of hypertrophic cardiomyopathy (RAS-HCM). Unlike primary HCM (P-HCM), the risk of sudden cardiac death (SCD) and long-term survival in RAS-HCM are poorly understood., Objectives: The study's objective was to compare transplant-free survival, incidence of SCD, and implantable cardioverter-defibrillator (ICD) use between RAS-HCM and P-HCM patients., Methods: In an international, 21-center cohort study, we analyzed phenotype-positive pediatric RAS-HCM (n = 188) and P-HCM (n = 567) patients. The between-group differences in cumulative incidence of all outcomes from first evaluation were compared using Gray's tests, and age-related hazard of all-cause mortality was determined., Results: RAS-HCM patients had a lower median age at diagnosis compared to P-HCM (0.9 years [IQR: 0.2-5.0 years] vs 9.8 years [IQR: 2.0-13.9 years], respectively) (P < 0.001). The 10-year cumulative incidence of SCD from first evaluation was not different between RAS-HCM and P-HCM (4.7% vs 4.2%, respectively; P = 0.59). The 10-year cumulative incidence of nonarrhythmic deaths or transplant was higher in RAS-HCM compared with P-HCM (11.0% vs 5.4%, respectively; P = 0.011). The 10-year cumulative incidence of ICD insertions, however, was 5-fold lower in RAS-HCM compared with P-HCM (6.9% vs 36.6%; P < 0.001). Nonarrhythmic deaths occurred primarily in infancy and SCD primarily in adolescence., Conclusions: RAS-HCM was associated with a higher incidence of nonarrhythmic death or transplant but similar incidence of SCD as P-HCM. However, ICDs were used less frequently in RAS-HCM compared to P-HCM. In addition to monitoring for heart failure and timely consideration of advanced heart failure therapies, better risk stratification is needed to guide ICD practices in RAS-HCM., Competing Interests: Funding Support and Author Disclosures The project was supported through funding from the Ted Rogers Centre for Heart Research, the Heart and Stroke Foundation/Robert M Freedom Chair, and the Canadian Institutes of Health Research to Dr Mital. Dr Lynch is supported by a Heart Failure Research Fellowship from Bristol Myers Squibb, Mitacs, and Myant. Dr Mital has served as a consultant for Bristol Myers Squibb and Tenaya Therapeutics; and has received unrestricted education funding from Bristol Myers Squibb. Dr Conway has served as a medical monitor for the PumpKIN trial; and has received unrestricted education funding from Abbott. Dr Rossano has served as a consultant for Merck, Bayer, Myokardia, and Cytokinetics. Dr Kantor has served as a consultant for Novartis and AstraZeneca. Dr Balaji has served as a consultant for Milestone Pharmaceuticals and Janssen Pharmaceuticals; and has received a research support grant from the Medtronic External Research Program. Dr Godown has served as a consultant for Daiichi-Sankyo. Dr Aziz has served on the Medical Advisory Board for Medtronic. Dr Jeewa has served as a medical monitor for the PumpKIN trial; and has served as a consultant for Abbott. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Atrial arrhythmia's (AA) following lung transplant in adults are a well-described clinical finding. In pediatrics, however, there are limited data with some reports suggesting that arrhythmias are rare., Methods: We performed a single-center retrospective review of lung transplant recipients from January 2013 to June 2020. A detailed evaluation of clinical characteristics, presence of arrhythmias, and outcomes was completed. Arrhythmias were documented based on inpatient telemetry or remote Holter monitoring. Analyses assessing risk factors for arrhythmias and associations with clinical outcomes were performed., Results: Ninety-one lung transplants were performed in 90 patients. Post-operative AA occurred following 19% transplants. Ectopic atrial tachycardia was seen in 14%, atrial flutter in 2%, and a combination in 2%. The majority of these arrhythmias occurred within the first 45 days post-operatively. Antiarrhythmic treatment was required in 59%, but none required ablation or electrical cardioversion. In patients followed for a year or more, 88% had resolution of their arrhythmia. Arrhythmias were not associated with mortality. In further analysis, however, the presence of arrhythmia was associated with an increased length of ICU stay (median of 12 days (IQR 6, 23) versus 5 days (IQR 4, 9); p = .019) and overall length of hospital stay (median of 26 days (IQR 19, 36) versus 17 days (IQR 19, 36); p = .043)., Conclusions: Atrial tachyarrhythmias after lung transplantation are common in the pediatric population and usually occur early. Although they frequently require medical therapy and are associated with longer stays, there is no associated increased mortality. In addition, the arrhythmias typically self-resolve., (© 2022 Wiley Periodicals LLC.)

Background: Atrial standstill (AS) is a rare condition characterized by absence of electrical activity within the atria. Studies to date have been limited., Objectives: The authors sought to describe the clinical characteristics, genetics, and outcomes of patients with AS., Methods: This was a retrospective multicenter study of patients <18 years at AS diagnosis, defined as absence of atrial activity documented during an electrophysiology study, device placement, or noninvasive rhythm tracings and confirmed by echocardiogram. Patients with acquired disorders were excluded. Clinical details and genetic variants were recorded and analyzed., Results: Twenty patients were diagnosed at a median age of 6.6 years (IQR: 2.9-10.8 years). Arrhythmias included 16 (80%) with atrial/supraventricular arrhythmias and 8 (40%) with ventricular tachycardia, including 4 with cardiac arrests. A type 1 Brugada pattern was documented in 4. Pacemakers were implanted in 18 (90%). Although atrial leads were attempted in 15, only 4 achieved pacing at implantation. During a median follow-up of 6.9 years (IQR: 1.2-13.3 years), 7 (35%) had thromboembolic events. Of these, none had atrial pacing, 6 were not on anticoagulation, and 1 was on aspirin. Genetic testing identified SCN5A variants in 13 patients (65%). Analyses suggest SCN5A loss-of-function may be one mechanism driving AS. Ventricular arrhythmias and cardiac arrest were more commonly seen in patients with biallelic SCN5A variants., Conclusions: AS may be associated with loss-of-function SCN5A variants. Patients demonstrate atrial and ventricular arrhythmias, and may present challenges during device placement. Patients without the capacity for atrial pacing are at risk for thromboembolic events and warrant anticoagulation., Competing Interests: Funding Support and Author Disclosures Dr Miyake is supported by National Heart, Lung, and Blood Institute grant K23HL136932. Dr Chiang is supported by the Leducq Foundation and a National Institutes of Health T32 grant from the National Human Genome Research Institute (#1T32HG010464). The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: TANGO2 deficiency disorder (TDD) is an autosomal recessive disease associated with metabolic crisis, lethal cardiac arrhythmias, and cardiomyopathy. Data regarding treatment, management, and outcomes of cardiac manifestations of TDD are lacking., Objective: The purpose of this study was to describe TDD-related cardiac crises., Methods: Retrospective multicenter chart review was made of TDD patients admitted with cardiac crises, defined as development of ventricular tachycardia (VT), cardiomyopathy, or cardiac arrest during metabolic crises., Results: Twenty-seven children were admitted for 43 cardiac crises (median age 6.4 years; interquartile range [IQR] 2.4-9.8 years) at 14 centers. During crisis, QTc prolongation occurred in all (median 547 ms; IQR 504-600 ms) and a type I Brugada pattern in 8 (26%). Arrhythmias included VT in 21 (78%), supraventricular tachycardia in 3 (11%), and heart block in 1 (4%). Nineteen patients (70%) developed cardiomyopathy, and 20 (74%) experienced a cardiac arrest. There were 10 deaths (37%), 6 related to arrhythmias. In 5 patients, recalcitrant VT occurred despite use of antiarrhythmic drugs. In 6 patients, arrhythmias were controlled after extracorporeal membrane oxygenation (ECMO) support; 5 of these patients survived. Among 10 patients who survived VT without ECMO, successful treatment included intravenous magnesium, isoproterenol, and atrial pacing in multiple cases and verapamil in 1 patient. Initiation of feeds seemed to decrease VT events., Conclusion: TDD-related cardiac crises are associated with a high risk of arrhythmias, cardiomyopathy, cardiac arrest, and death. Although further studies are needed, early recognition and appropriate treatment are critical. Acutely, intravenous magnesium, isoproterenol, atrial pacing, and ECMO as a last resort seem to be the best current treatment options, and early initiation of feeds may prevent VT events., (Copyright © 2022. Published by Elsevier Inc.)

Background: Data regarding recurrence risk among infants with supraventricular tachycardia (SVT) are limited., Objectives: The purpose of this study was to determine incidence and factors associated with SVT recurrence., Methods: This was a retrospective single-center study (1984-2020) with prospective phone follow-up of infants with structurally normal hearts diagnosed at age ≤1 year with re-entrant SVT. Primary outcome was first SVT recurrence after hospital discharge. Classification and regression tree analysis was performed to determine a risk algorithm., Results: Among 460 infants (62% male), 87% were diagnosed at ≤60 days of age (median 13 days; IQR: 1-31 days). During a median follow-up of 5.2 years (IQR: 1.8-11.2 years), 33% had recurrence. On multivariable analysis, factors associated with recurrence included: fetal or late (>60 days) diagnosis (HR: 1.90; 95% CI: 1.26-2.86; and HR: 1.73; 95% CI: 1.07-2.77, respectively), Wolff-Parkinson-White (WPW) syndrome (HR: 2.46; 95% CI: 1.75-3.45), and need for multi-antiarrhythmic or second-line therapy (HR: 2.08; 95% CI: 1.45-2.99). Based on the classification and regression tree analysis, WPW incurred the highest risk. Among those without WPW, age at diagnosis was the most important factor predicting risk. Fetal or late diagnosis incurred higher risk, and if multi-antiarrhythmic or second-line therapy was also required, risk nearly doubled. Infants without WPW, who were diagnosed early (0-60 days), and who were discharged on propranolol were at lowest recurrence risk., Conclusions: Infants with SVT are most likely to be diagnosed at ≤60 days and be male. Risk factors for recurrence (occurred in 33%), present at time of diagnosis, include WPW, fetal or late diagnosis, and multi-antiarrhythmic or second-line therapy. Infants with early diagnosis, without WPW, and discharged on first-line monotherapy are at lowest recurrence risk., Competing Interests: Funding Support and Author Disclosures Dr Miyake is supported by National Heart, Lung, and Blood Institute K23HL136932. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2022 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Introduction: Ablation for atrioventricular nodal reentrant tachycardia (AVNRT) classically utilizes evaluation of signal morphology within the anatomic region of the slow pathway (SP), which involves subjectivity. Ripple mapping (RM; CARTO-3 © Biosense Webster Inc) displays each electrogram at its three-dimensional coordinate as a bar changing in length according to its voltage-time relationship. This allows prolonged, low-amplitude signals to be displayed in their entirety, helping identify propagation in low-voltage areas. We set out to evaluate the ability of RM to locate the anatomic site of the SP and assess its use in guiding ablation for AVNRT., Methods: Patients ≤18 years with AVNRT in the EP laboratory between 2017 and 2021 were evaluated. RM was performed to define region of SP conduction in patients from 2019 to 2021, whereas standard electro-anatomical mapping was used from 2017 to 2019. All ablations were performed using cryotherapy. Demographics, outcomes, and analysis of variance in number of test lesions until success was compared between groups., Results: A total of 115 patients underwent AVRNT ablation during the study; 46 patients were in the RM group and 69 were in the control group. There were no demographic differences between groups. All procedures, in both groups, were acutely successful. In RM group, 89% of first successful lesions were within 4 mm of the predicted site. There was significantly reduced variability in number of test lesions until success in the RM group (p = .01)., Conclusion: RM is a novel technique that can help identify SP location, allowing for successful ablation of AVNRT with decreased variability., (© 2022 Wiley Periodicals LLC.)

Objectives: To assess whether padded headgear was associated with incidence of suspected sports-related concussion, non-sports-related concussion head injury, and injuries to other body regions in junior Australian football., Design: Prospective cohort injury surveillance., Methods: There were 400 junior players (42.5% female) enrolled across two seasons. Suspected sports-related concussion was defined by detection of observable signs on the field and medical assessment or missed match(es) due to suspected sports-related concussion. Non-sports-related concussion head injury and injuries to other body regions were defined as those that received medical assessment or resulted in a missed match., Results: There were 20 teams monitored over 258 matches. 204 players (2484 player hours) wore mandated headgear throughout the season and 196 (2246 player hours) did not. The incidence rate of suspected sports-related concussion was 3.17 (95% confidence interval: 3.04-3.30) per 1000 player-hours and no differences were observed between males and females (risk ratio 1.11; 95% confidence interval: 0.40-3.06). Headgear use was not associated with suspected sports-related concussion (risk ratio 1.09; 95% confidence interval: 0.41-2.97), non-sports-related concussion head injury (risk ratio 0.27; 95% confidence interval: 0.06-1.31), or injuries to other body regions (risk ratio 1.41; 95% confidence interval: 0.79-2.53)., Conclusions: Headgear use was not associated with reduced risk of suspected sports-related concussion, non-sports-related concussion head injury or injuries to other body regions. There was no difference in the rate of suspected sports-related concussion in female compared to male players, however, rates of non-sports-related concussion head injury and injuries to other body regions were higher in male players., (Copyright © 2021 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.)

Background: Junctional ectopic tachycardia (JET) is a common arrhythmia after congenital heart disease surgery. There is variability in the choice of antiarrhythmic therapy, with amiodarone used commonly. Intravenous (IV) sotalol is a newly available agent that may be useful for JET., Objective: The purpose of this study was to evaluate the safety and efficacy of IV sotalol for postoperative JET and compare outcomes with IV amiodarone., Methods: This is a retrospective single-center study of all patients who received IV sotalol or IV amiodarone for postoperative JET at Texas Children's Hospital from December 15, 2015, to December 15, 2020. Data included antiarrhythmic efficacy, hemodynamics, and adverse effects. Successful JET control was defined as a decrease in JET rate to <170 beats/min (or decrease by >20%), or conversion to sinus rhythm, with persistent control over 24 hours without requiring alternative antiarrhythmics or mechanical support., Results: A total of 32 patients (median age 71 days; interquartile range 17-221 days) received IV amiodarone (n = 20 [62%]) or IV sotalol (n = 12 [38%]) for postoperative JET. Amiodarone was successful in treating JET in 75% of cases; sotalol was successful in 83%. The JET rate decreased faster over the first 90 minutes after a sotalol bolus (25 beats/min per hour) than after an amiodarone bolus (8 beats/min per hour) (P < .01); no heart rate difference was seen after 24 hours. Amiodarone infusion was discontinued early because of hypotension/bradycardia in 2 patients; this was not required in any patients receiving sotalol., Conclusion: For children with postoperative JET, both IV sotalol and amiodarone are safe and efficacious. IV sotalol may lead to a faster improvement in heart rate., (Copyright © 2021 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)