Pediatric ECG-Based Deep Learning to Predict Left Ventricular Dysfunction and Remodeling.

BACKGROUND: Artificial intelligence-enhanced ECG analysis shows promise to detect ventricular dysfunction and remodeling in adult populations. However, its application to pediatric populations remains underexplored. METHODS: A convolutional neural network was trained on paired ECG-echocardiograms (≤2 days apart) from patients ≤18 years of age without major congenital heart disease to detect human expert-classified greater than mild left ventricular (LV) dysfunction, hypertrophy, and dilation (individually and as a composite outcome). Model performance was evaluated on single ECG-echocardiogram pairs per patient at Boston Children's Hospital and externally at Mount Sinai Hospital using area under the receiver operating characteristic curve (AUROC) and area under the precision-recall curve (AUPRC). RESULTS: The training cohort comprised 92 377 ECG-echocardiogram pairs (46 261 patients; median age, 8.2 years). Test groups included internal testing (12 631 patients; median age, 8.8 years; 4.6% composite outcomes), emergency department (2830 patients; median age, 7.7 years; 10.0% composite outcomes), and external validation (5088 patients; median age, 4.3 years; 6.1% composite outcomes) cohorts. Model performance was similar on internal test and emergency department cohorts, with model predictions of LV hypertrophy outperforming the pediatric cardiologist expert benchmark. Adding age and sex to the model added no benefit to model performance. When using quantitative outcome cutoffs, model performance was similar between internal testing (composite outcome: AUROC, 0.88, AUPRC, 0.43; LV dysfunction: AUROC, 0.92, AUPRC, 0.23; LV hypertrophy: AUROC, 0.88, AUPRC, 0.28; LV dilation: AUROC, 0.91, AUPRC, 0.47) and external validation (composite outcome: AUROC, 0.86, AUPRC, 0.39; LV dysfunction: AUROC, 0.94, AUPRC, 0.32; LV hypertrophy: AUROC, 0.84, AUPRC, 0.25; LV dilation: AUROC, 0.87, AUPRC, 0.33), with composite outcome negative predictive values of 99.0% and 99.2%, respectively. Saliency mapping highlighted ECG components that influenced model predictions (precordial QRS complexes for all outcomes; T waves for LV dysfunction). High-risk ECG features include lateral T-wave inversion (LV dysfunction), deep S waves in V1 and V2 and tall R waves in V6 (LV hypertrophy), and tall R waves in V4 through V6 (LV dilation). CONCLUSIONS: This externally validated algorithm shows promise to inexpensively screen for LV dysfunction and remodeling in children, which may facilitate improved access to care by democratizing the expertise of pediatric cardiologists.

Socioeconomic Factors Influencing Pediatric Peak Oxygen Consumption Prediction.

OBJECTIVE: To determine if socioeconomic status (SES) has a greater effect than standard demographic values on predicted peak oxygen consumption (pVO2). STUDY DESIGN: We conducted a single-institution, retrospective analysis of maximal cardiopulmonary exercise test (CPET) data from 2010 to 2020 for healthy patients age <19 years with body mass index (BMI) percentile (BMI%) between 5-95. Data were sorted by self-identified race, BMI%, and adjusted gross income (AGI); AGI served as a surrogate for SES. Mean percent predicted pVO2 (pppVO2) was compared between groups. Linear regression was used to adjust for differences. RESULTS: A total of 541 CPETs met inclusion criteria. Mean pppVO2 was 97% ± 22.6 predicted (P < .01) with 30% below criterion standard for normal (85% predicted). After excluding unknown AGI and race, 418 CPETs remained. Mean pppVO2 was lower for Blacks (n = 36) and Latinx (n = 26) compared with Whites (n = 333, P < .01). Mean pppVO2 declined as AGI decreased (P < .01). The differences in pppVO2 between racial categories remained significant when adjusted for BMI% (Black r = -7.3, P = .035; Latinx r = -15.4, P < .01). These differences both decreased in magnitude and were no longer significant when adjusted for AGI (Black r = -6.0, P = .150; Latinx r = -9.3, P = .06). CONCLUSIONS: Lower SES correlates with lower measured cardiovascular fitness and may confound data interpretation. When using normative reference ranges in clinical decision making, providers should recognize that social determinants of health may influence predicted fitness. Social inequities should be considered when assessing pediatric cardiovascular fitness.

Limited Relationship Between Echocardiographic Measures and Electrocardiographic Markers of Left Ventricular Size in Healthy Children.

Pediatric ECG standards have been defined without echocardiographic confirmation of normal anatomy. The Pediatric Heart Network Normal Echocardiogram Z-score Project provides a racially diverse group of healthy children with normal echocardiograms. We hypothesized that ECG and echocardiographic measures of left ventricular (LV) dimensions are sufficiently correlated in healthy children to imply a clinically meaningful relationship. This was a secondary analysis of a previously described cohort including 2170 digital ECGs. The relationship between 6 ECG measures associated with LV size were analyzed with LV Mass (LVMass-z) and left ventricular end-diastolic volume (LVEDV-z) along with 11 additional parameters. Pearson or Spearman correlations were calculated for the 78 ECG-echocardiographic pairs with regression analyses assessing the variance in ECG measures explained by variation in LV dimensions and demographic variables. ECG/echocardiographic measurement correlations were significant and concordant in 41/78 (53%), though many were significant and discordant (13/78). Of the 6 ECG parameters, 5 correlated in the clinically predicted direction for LV Mass-z and LVEDV-z. Even when statistically significant, correlations were weak (0.05-0.24). R2 was higher for demographic variables than for echocardiographic measures or body surface area in all pairs, but remained weak (R2 ≤ 0.17). In a large cohort of healthy children, there was a positive association between echocardiographic measures of LV size and ECG measures of LVH. These correlations were weak and dependent on factors other than echocardiographic or patient derived variables. Thus, our data support deemphasizing the use of solitary, traditional measurement-based ECG markers traditionally thought to be characteristic of LVH as standalone indications for further cardiac evaluation of LVH in children and adolescents.

Prevalence of adverse events in pronated intubated adult COVID-19 patients: A systematic review with meta-analysis.

AIM: To present the pooled estimated prevalence of adverse events in pronated intubated adult COVID-19 patients. DESIGN: A systematic review and meta-analysis. DATA SOURCES: This study used the Cochrane Library, CINAHL, Embase, LILACS, Livivo, PubMed, Scopus, and Web of Science databases as data sources. METHODS: The studies were meta-analysed using JAMOVI 1.6.15 software. A random-effects model was used to identify the global prevalence of adverse events, confidence intervals and the heterogeneity data. Risk of bias was assessed using the Joanna Briggs Institute tool, and the certainty of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation approach. RESULTS: Of the 7904 studies identified, 169 were included for full reading, and 10 were included in the review. The most prevalent adverse events were pressure injuries (59%), haemodynamic instability (23%), death (17%) and device loss or traction (9%). CONCLUSION: The most prevalent adverse events in mechanically ventilated pronated patients with COVID-19 are pressure injuries, presence of haemodynamic instability, death and device loss or traction. IMPLICATIONS FOR THE PATIENT CARE: The evidence identified in this review can help improve the quality and safety of patient care by helping to design care protocols to avoid the development of adverse events that can cause permanent sequelae in these patients. IMPACT: This systematic review addressed the adverse events related to prone position in intubated adult COVID-19 patients. We identified that the most prevalent adverse events in these patients were pressure injuries, haemodynamic instability, device loss or traction and death. The results of this review may influence the clinical practice of nurses who work in intensive care units and, consequently, the nursing care provided not only to COVID-19 patients but for all intubated patients due to other reasons in intensive care units. REPORTING METHOD: This systematic review adhered to the PRISMA reporting guideline. PATIENT OR PUBLIC CONTRIBUTION: As this is a systematic review, we analysed data from primary studies conducted by many researchers. Thus, there was no patient or public contribution in this review.

Racial and Socioeconomic Equity of Tecovirimat Treatment during the 2022 Mpox Emergency, New York, New York, USA.

We assessed tecovirimat treatment equity for 3,740 mpox patients in New York, New York, USA, during the 2022 mpox emergency; 32.4% received tecovirimat. Treatment rates by race/ethnicity were 38.8% (White), 31.3% (Black/African American), 31.0% (Hispanic/Latino), and 30.1% (Asian/Pacific Islander/other). Future public health emergency responses must prioritize institutional and structural racism mitigation.

Retroflexed catheter course reduces the risk of right free wall accessory pathway recurrence.

INTRODUCTION: Accessory atrioventricular pathways (APs) may mediate atrioventricular reciprocating tachycardia and, in some cases, have the potential to conduct atrial tachycardia rapidly, which can be life threatening. While catheter ablation can be curative, ablation of right free wall APs is associated with a high rate of recurrence, likely secondary to reduced catheter stability along the right free wall atrioventricular groove. We sought to identify characteristics associated with a lower rate of recurrence and hypothesized ablation lesions placed on the ventricular side of the atrioventricular groove using a retroflexed catheter approach would decrease rates of recurrence. METHODS AND RESULTS: Retrospective chart review of patients who underwent catheter ablation of a right free wall AP from January 1, 2008 through June 1, 2021 with >2 months follow up. Cox proportional hazards regression was used to identify relationships between predictor variables and AP recurrence. We identified 95 patients who underwent ablation of 98 right free wall APs. Median age was 13.1 years and median weight at ablation was 52.3 kg. Overall, 23/98 (23%) APs recurred. Use of a retroflexed catheter course approaching the atrioventricular groove from the ventricular aspect was associated with reduced risk of AP recurrence with (univariable hazard ratio of 0.10 [95% confidence interval: 0.01-0.78]), which remained significant in multiple two variable Cox proportional hazards models. CONCLUSION: Use of a retroflexed catheter course is associated with a reduced likelihood of AP recurrence. This approach results in improved catheter stability and should be considered for ablation of right free wall APs.

Medical cardioversion of atrial fibrillation and flutter with class IC antiarrhythmic drugs in young patients with and without congenital heart disease.

INTRODUCTION: The use of flecainide and propafenone for medical cardioversion of atrial fibrillation (AF) and atrial flutter/intra-atrial reentrant tachycardia (IART) is well-described in adults without congenital heart disease (CHD). Data are sparse regarding their use for the same purpose in adults with CHD and in adolescent patients with anatomically normal hearts and we sought to describe the use of class IC drugs in this population and identify factors associated with decreased likelihood of success. METHODS: Single center retrospective cohort study of patients who received oral flecainide or propafenone for medical cardioversion of AF or IART from 2000 to 2022. The unit of analysis was each episode of AF/IART. We performed a time-to-sinus rhythm analysis using a Cox proportional hazards model clustering on the patient to identify factors associated with increased likelihood of success. RESULTS: We identified 45 episodes involving 41 patients. As only episodes of AF were successfully cardioverted with medical therapy, episodes of IART were excluded from our analyses. Use of flecainide was the only factor associated with increased likelihood of success. There was a statistically insignificant trend toward decreased likelihood of success in patients with CHD. CONCLUSIONS: Flecainide was more effective than propafenone. We did not detect a difference in rate of conversion to sinus rhythm between patients with and without CHD and were likely underpowered to do so, however, there was a trend toward decreased likelihood of success in patients with CHD. That said, medical therapy was effective in >50% of patients with CHD with AF.

FORCE Risk Stratification Tool for Pediatric Cardiac Rehabilitation and Fitness Programs.

Risk stratification is required to set an exercise prescription for cardiac rehabilitation, but an optimal scheme for congenital heart disease (CHD) is unknown. We piloted a system based on hemodynamic rather than anatomic factors: function, oxygen level, rhythm, complex/coronary anatomy, and elevated load (FORCE). Feasibility, efficacy, and safety of the FORCE tool were evaluated. Patients < 22 years old participating in the Cardiac Fitness Program at Boston Children's Hospital between 02/2017 and 12/2021 were retrospectively analyzed. Assigned FORCE levels, anatomy, adverse events, fitness and exercise test data were collected. Of 63 attempts at FORCE classification, 62 (98%) were successfully classified while one with restrictive cardiomyopathy was not. Thirty-nine (62%) were FORCE 1, 16 (25%) were FORCE 2, and seven (11%) were FORCE 3. Almost half of FORCE 1 patients had simple or complex CHD and the majority of FORCE 2 patients had single ventricle CHD. FORCE 3 patients were more likely to have serious arrhythmias or cardiomyopathy than those in FORCE 1 or 2 (p < 0.001). Postural orthostatic tachycardia syndrome patients appeared in FORCE 1 only. No adverse events occurred over 958 total sessions. The total number of fitness sessions/participant was similar across FORCE levels. It was feasible to risk stratify patients with CHD using a clinical FORCE tool. The tool was effective in categorizing patients and simple to use. No adverse events occurred with fitness training over nearly 1000 exercise training sessions. Adding diastolic dysfunction to the original model may add utility.

Foveal Hypoplasia in CRB1-Related Retinopathies.

The CRB1 gene plays a role in retinal development and its maintenance. When disrupted, it gives a range of phenotypes such as early-onset severe retinal dystrophy/Leber congenital amaurosis (EOSRD/LCA), retinitis pigmentosa (RP), cone-rod dystrophy (CORD) and macular dystrophy (MD). Studies in CRB1 retinopathies have shown thickening and coarse lamination of retinal layers resembling an immature retina. Its role in foveal development has not yet been described; however, this retrospective study is the first to report foveal hypoplasia (FH) presence in a CRB1-related retinopathy cohort. Patients with pathogenic biallelic CRB1 variants from Moorfields Eye Hospital, London, UK, were collected. Demographic, clinical data and SD-OCT analyses with FH structural grading were performed. A total of 15 (48%) patients had EOSRD/LCA, 11 (35%) MD, 3 (9%) CORD and 2 (6%) RP. FH was observed in 20 (65%; CI: 0.47-0.79) patients, all of whom were grade 1. A significant difference in BCVA between patients with FH and without was found (p = 0.014). BCVA continued to worsen over time in both groups (p < 0.001), irrespective of FH. This study reports FH in a CRB1 cohort, supporting the role of CRB1 in foveal development. FH was associated with poorer BCVA and abnormal retinal morphology. Nonetheless, its presence did not alter the disease progression.

Brain-based measures of nociception during general anesthesia with remifentanil: A randomized controlled trial.

BACKGROUND: Catheter radiofrequency (RF) ablation for cardiac arrhythmias is a painful procedure. Prior work using functional near-infrared spectroscopy (fNIRS) in patients under general anesthesia has indicated that ablation results in activity in pain-related cortical regions, presumably due to inadequate blockade of afferent nociceptors originating within the cardiac system. Having an objective brain-based measure for nociception and analgesia may in the future allow for enhanced analgesic control during surgical procedures. Hence, the primary aim of this study is to demonstrate that the administration of remifentanil, an opioid widely used during surgery, can attenuate the fNIRS cortical responses to cardiac ablation. METHODS AND FINDINGS: We investigated the effects of continuous remifentanil on cortical hemodynamics during cardiac ablation under anesthesia. In a randomized, double-blinded, placebo (PL)-controlled trial, we examined 32 pediatric patients (mean age of 15.8 years,16 females) undergoing catheter ablation for cardiac arrhythmias at the Cardiology Department of Boston Children's Hospital from October 2016 to March 2020; 9 received 0.9% NaCl, 12 received low-dose (LD) remifentanil (0.25 mcg/kg/min), and 11 received high-dose (HD) remifentanil (0.5 mcg/kg/min). The hemodynamic changes of primary somatosensory and prefrontal cortices were recorded during surgery using a continuous wave fNIRS system. The primary outcome measures were the changes in oxyhemoglobin concentration (NadirHbO, i.e., lowest oxyhemoglobin concentration and PeakHbO, i.e., peak change and area under the curve) of medial frontopolar cortex (mFPC), lateral prefrontal cortex (lPFC) and primary somatosensory cortex (S1) to ablation in PL versus remifentanil groups. Secondary measures included the fNIRS response to an auditory control condition. The data analysis was performed on an intention-to-treat (ITT) basis. Remifentanil group (dosage subgroups combined) was compared with PL, and a post hoc analysis was performed to identify dose effects. There were no adverse events. The groups were comparable in age, sex, and number of ablations. Results comparing remifentanil versus PL show that PL group exhibit greater NadirHbO in inferior mFPC (mean difference (MD) = 1.229, 95% confidence interval [CI] = 0.334, 2.124, p < 0.001) and superior mFPC (MD = 1.206, 95% CI = 0.303, 2.109, p = 0.001) and greater PeakHbO in inferior mFPC (MD = -1.138, 95% CI = -2.062, -0.214, p = 0.002) and superior mFPC (MD = -0.999, 95% CI = -1.961, -0.036, p = 0.008) in response to ablation. S1 activation from ablation was greatest in PL, then LD, and HD groups, but failed to reach significance, whereas lPFC activation to ablation was similar in all groups. Ablation versus auditory stimuli resulted in higher PeakHbO in inferior mFPC (MD = 0.053, 95% CI = 0.004, 0.101, p = 0.004) and superior mFPC (MD = 0.052, 95% CI = 0.013, 0.091, p < 0.001) and higher NadirHbO in posterior superior S1 (Pos. SS1; MD = -0.342, 95% CI = -0.680, -0.004, p = 0.007) during ablation of all patients. Remifentanil group had smaller NadirHbO in inferior mFPC (MD = 0.098, 95% CI = 0.009, 0.130, p = 0.003) and superior mFPC (MD = 0.096, 95% CI = 0.008, 0.116, p = 0.003) and smaller PeakHbO in superior mFPC (MD = -0.092, 95% CI = -0.680, -0.004, p = 0.007) during both the stimuli. Study limitations were small sample size, motion from surgery, indirect measure of nociception, and shallow penetration depth of fNIRS only allowing access to superficial cortical layers. CONCLUSIONS: We observed cortical activity related to nociception during cardiac ablation under general anesthesia with remifentanil. It highlights the potential of fNIRS to provide an objective pain measure in unconscious patients, where cortical-based measures may be more accurate than current evaluation methods. Future research may expand on this application to produce a real-time indication of pain that will aid clinicians in providing immediate and adequate pain treatment. TRIAL REGISTRATION: ClinicalTrials.gov NCT02703090.

Monofractal analysis of functional magnetic resonance imaging: An introductory review.

The following review will aid readers in providing an overview of scale-free dynamics and monofractal analysis, as well as its applications and potential in functional magnetic resonance imaging (fMRI) neuroscience and clinical research. Like natural phenomena such as the growth of a tree or crashing ocean waves, the brain expresses scale-invariant, or fractal, patterns in neural signals that can be measured. While neural phenomena may represent both monofractal and multifractal processes and can be quantified with many different interrelated parameters, this review will focus on monofractal analysis using the Hurst exponent (H). Monofractal analysis of fMRI data is an advanced analysis technique that measures the complexity of brain signaling by quantifying its degree of scale-invariance. As such, the H value of the blood oxygenation level-dependent (BOLD) signal specifies how the degree of correlation in the signal may mediate brain functions. This review presents a brief overview of the theory of fMRI monofractal analysis followed by notable findings in the field. Through highlighting the advantages and challenges of the technique, the article provides insight into how to best conduct fMRI fractal analysis and properly interpret the findings with physiological relevance. Furthermore, we identify the future directions necessary for its progression towards impactful functional neuroscience discoveries and widespread clinical use. Ultimately, this presenting review aims to build a foundation of knowledge among readers to facilitate greater understanding, discussion, and use of this unique yet powerful imaging analysis technique.

Supraventricular Tachycardia in Infants With Congenital Diaphragmatic Hernia: Prevalence, Associations, and Outcomes.

OBJECTIVES: To characterize the prevalence, associations, management, and outcomes of supraventricular tachycardia (SVT) in neonates with congenital diaphragmatic hernia (CDH). DESIGN: Retrospective chart and cardiology code review within a cohort of patients with CDH was used to define a subpopulation with atrial arrhythmia. SVT mechanisms were confirmed by electrocardiogram analysis. Cox proportional hazard regression identified risk factors for SVT and association with clinical outcomes. SETTING: Medical Surgical ICU in a single, tertiary center, Boston Children's Hospital. PATIENTS: Eligible patients included neonates presenting with classic Bochdalek posterolateral CDH between 2005 and 2017, excluding newborns with Morgagni hernia or late diagnoses of CDH (>28 d). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: SVT arose in 25 of 232 neonates with CDH, (11%); 14 of 25 infants (56%) had recurrent SVT; atrioventricular node-dependent tachycardia was the most frequent mechanism (32%). The majority (71%) of SVT episodes received intervention. Nine patients (36%) received preventative antiarrhythmic medications. SVT was associated with lower Apgar score at 1 min, structural heart disease, larger defect size, extracorporeal membrane oxygenation (ECMO) support, and prostaglandin therapy for ductal patency as well as hospital stay greater than or equal to 8 weeks and use of supplemental oxygen at discharge. CONCLUSIONS: SVT can occur in neonates with CDH and frequently requires treatment. Odds of occurrence are increased with greater CDH disease severity, ECMO, and prostaglandin use. In unadjusted logistic regression analysis, SVT was associated with adverse hospital outcomes, underscoring the importance of recognition and management in this vulnerable population.

Assessment of Exercise Function in Children and Young Adults with Hypertrophic Cardiomyopathy and Correlation with Transthoracic Echocardiographic Parameters.

Exercise function is well characterized in adults with hypertrophic cardiomyopathy (HCM); however, there is a paucity of data in children and young adults with HCM. Here we sought to characterize exercise function in young people with HCM, understand limitations in exercise function by correlating exercise function parameters with echocardiogram parameters and identify prognostic value of exercise parameters. We performed a retrospective, single-center cohort study characterizing exercise function in patients < 26 years old with HCM undergoing cardiopulmonary exercise testing (CPET). Patients with syndromic HCM or submaximal effort were excluded. We compared exercise function in this cohort to population normal values and measured changes in exercise function over time. We correlated exercise function parameters with echocardiographic parameters and investigated the relationship between exercise test parameters and a clinical composite outcome comprised of significant ventricular arrhythmia, death, or heart transplantation. We identified 229 CPETs performed by 117 patients (mean age at time of first CPET 15.6 ± 3.2 years). Mean %-predicted peak VO2, O2 pulse, and peak heart rate were statistically significantly depressed compared to population normal values and exercise function gradually worsened over time. Abnormal exercise testing correlated closely with echocardiographic indices of diastolic dysfunction. There was a trend toward increased incidence of poor clinical outcome in patients with abnormal exercise function. While adverse clinical outcomes were rare, normal exercise function appears to be a marker of low risk for adverse clinical outcomes in this population.

Activity During the COVID-19 Pandemic in Children with Cardiac Rhythm Management Devices.

Decreased physical activity is associated with cardiovascular, metabolic and mental health disease. While decreases in physical activity during the COVID-19 pandemic have been described in the general population, there is a paucity of data regarding children with underlying cardiovascular disease. We hypothesized there would be a decrease in physical activity at the onset of the COVID-19 pandemic. Performed a single-center, retrospective cohort study of children aged < 19 years with cardiac rhythm management devices. Patients were included if they had device-measured physical activity data from > 80% of dates from February 3, 2020 through June 30, 2020. Patients with significant neurologic/neuromuscular disease were excluded. We identified 144 patients with a median age of 15.4 years. 47% were female. 34% had congenital heart disease, 20% had cardiomyopathy, 19% had an inherited arrhythmia syndrome and 5% had atrioventricular block without congenital heart disease. 47% of patients had an implantable loop recorder, 29% had a permanent pacemaker and 24% had an implantable cardioverter-defibrillator. We observed a significant decrease in device-measured physical activity from baseline (February 3-March 9), with up to a 21% decrease in physical activity during mid-March through early May. Activity levels returned to pre-pandemic levels in June. Physical activity sharply declined in children with cardiac rhythm management devices at the onset of the COVID-19 pandemic. These data highlight the importance of finding strategies to maintain physical activity during the current pandemic and future public health crises.

Electrocardiogram as a Lyme Disease Screening Test.

OBJECTIVE: To examine the association between electrocardiographic (ECG) evidence of carditis at the time of Lyme disease evaluation and a diagnosis of Lyme disease. STUDY DESIGN: We performed an 8-center prospective cohort study of children undergoing emergency department evaluation for Lyme disease limited to those who had an ECG obtained by their treating clinicians. The study cardiologist reviewed all ECGs flagged as abnormal by the study sites to assess for ECG evidence of carditis. We defined Lyme disease as the presence of an erythema migrans lesion or a positive 2-tier Lyme disease serology. We used logistic regression to measure the association between Lyme disease and atrioventricular (AV) block or any ECG evidence of carditis. RESULTS: Of the 546 children who had an ECG obtained, 214 (39%) had Lyme disease. Overall, 42 children had ECG evidence of carditis, of whom 24 had AV block (20 first-degree). Of the patients with ECG evidence of carditis, only 21 (50%) had any cardiac symptoms. The presence of AV block (OR 4.7, 95% CI 1.8-12.1) and any ECG evidence of carditis (OR 2.3, 95% CI 1.2-4.3) were both associated with diagnosis of Lyme disease. CONCLUSIONS: ECG evidence of carditis, especially AV block, was associated with a diagnosis of Lyme disease. ECG evidence of carditis can be used as a diagnostic biomarker for Lyme disease to guide initial management while awaiting Lyme disease test results.

Care of Children with Supraventricular Tachycardia in the Emergency Department.

Prior studies have characterized children with supraventricular tachycardia (SVT) in inpatient settings, however there is a paucity of data regarding pediatric SVT in the Emergency Department (ED) setting. We sought to describe pediatric ED visits for SVT and assess whether variability exists in care. We performed a cross-sectional study of ED visits for SVT among children < 18 years old from 2010 to 2017 at 33 pediatric hospitals. Visits were included if made for a primary International Disease Classification Ninth or Tenth Revision diagnosis code for SVT and intravenous (IV) adenosine was given on the initial or 2nd hospital day. We evaluated factors associated with hospital admission using multivariate logistic regression and described variability in frequency of rate of hospitalization, second-line IV antiarrhythmic medication usage, and diagnostic testing across sites. We included 2329 ED visits made by 1738 children and the median patient age was 6.3 years (IQR 1.5-11.9). There were 2 deaths (0.1% of visits). Marked variability existed between centers in rates of admission to the hospital (range 17-85%) and ICU (range 4-60%). Factors associated with admission included: younger age, male sex and presence of comorbid conditions. A second IV antiarrhythmic agent was used in 17% of visits (range 4-41% across hospitals). There was variability in rates of diagnostic testing between centers [chest x-ray (range 10-47%), complete blood count (range 10-72%), electrolytes (range 22-86%), echocardiography (range 3-68%)]. Management of SVT is variable across pediatric hospitals, suggesting an opportunity for standardization in care.

Pacemaker use for the treatment of reflex-mediated syncope: 40-year experience at a single paediatric institution.

INTRODUCTION: Reflex-mediated syncope occurs in 15% of children and young adults. In rare instances, pacemakers are required to treat syncopal episodes associated with transient sinus pauses or atrioventricular block. This study describes a single centre experience in the use of permanent pacemakers to treat syncope in children and young adults. MATERIALS AND METHODS: Patients with significant pre-syncope or syncope and pacemaker implantation from 1978 to 2018 were reviewed. Data collected included the age of presentation, method of diagnosis, underlying rhythm disturbance, age at implant, type of pacemaker implanted, procedural complications and subsequent symptoms. RESULTS: Fifty patients were identified. Median age at time of the first syncopal episode was 10.2 (range 0.3-20.4) years, with a median implant age of 14.9 (0.9-34.3) years. Significant sinus bradycardia/pauses were the predominant reason for pacemaker implant (54%), followed by high-grade atrioventricular block (30%). Four (8%) patients had both sinus pauses and atrioventricular block documented. The majority of patients had dual-chamber pacemakers implanted (58%), followed by ventricular pacemakers (38%). Median follow-up was 6.7 (0.4-33.0) years. Post-implant, 4 (8%) patients continued to have syncope, 7 (14%) had complete resolution of their symptoms, and the remaining reported a decrease in their pre-syncopal episodes and no further syncope. Twelve (24%) patients had complications, including two infections and eight lead malfunctions. CONCLUSIONS: Paediatric patients with reflex-mediated syncope can be treated with pacing. Complication rates are high (24%); as such, permanent pacemakers should be reserved only for those in whom asystole from sinus pauses or atrioventricular block has been well documented.

Low mortality in fetal supraventricular tachycardia: Outcomes in a 30-year single-institution experience.

OBJECTIVES: To describe a single institutional experience managing fetuses with supraventricular tachycardia (SVT) and to identify associations between patient characteristics and fetal and postnatal outcomes. BACKGROUND: Sustained fetal SVT is associated with significant morbidity and mortality if untreated, yet the optimal management strategy remains unclear. METHODS: Retrospective cohort study including fetuses diagnosed with sustained SVT (>50% of the diagnostic echocardiogram) between 1985 and 2018. Fetuses with congenital heart disease were excluded. RESULTS: Sustained SVT was diagnosed in 65 fetuses at a median gestational age of 30 weeks (range, 14-37). Atrioventricular re-entrant tachycardia and atrial flutter were the most common diagnoses, seen in 41 and 16 cases, respectively. Moderate/severe ventricular dysfunction was present in 20 fetuses, and hydrops fetalis was present in 13. Of the 57 fetuses initiated on transplacental drug therapy, 47 received digoxin first-line, yet 39 of 57 (68%) required advanced therapy with sotalol, flecainide, or amiodarone. Rate or rhythm control was achieved in 47 of 57 treated fetuses. There were no cases of intrauterine fetal demise. Later gestational age at fetal diagnosis (odds ratio [OR], 1.1, 95% confidence interval [CI], 1.01-1.2, P = .02) and moderate/severe fetal ventricular dysfunction (OR, 6.1, 95% CI, 1.7-21.6, P = .005) were associated with postnatal SVT. Two postnatal deaths occurred. CONCLUSIONS: Fetuses with structurally normal hearts and sustained SVT can be effectively managed with transplacental drug therapy with minimal risk of intrauterine fetal demise. Treatment requires multiple antiarrhythmic agents in over half of cases. Later gestational age at fetal diagnosis and the presence of depressed fetal ventricular function, but not hydrops, predict postnatal arrhythmia burden.

Myelin water imaging and R2* mapping in neonates: Investigating R2* dependence on myelin and fibre orientation in whole brain white matter.

R2* relaxation provides a semiquantitative method of detecting myelin, iron and white matter fibre orientation angles. Compared with standard histogram-based analyses, angle-resolved analysis of R2* has previously been shown to substantially improve the detection of subtle differences in the brain between healthy siblings of subjects with multiple sclerosis and unrelated healthy controls. Neonates, who are born with very little myelin and iron, and an underdeveloped connectome, provide researchers with an opportunity to investigate whether R2* is intimately linked with fibre-angle or myelin content as it is in adults, which may in future studies be explored as a potential white matter developmental biomarker. Five healthy adult volunteers (mean age [±SD] = 31.2 [±8.3] years; three males) were recruited from Vancouver, Canada. Eight term neonates (mean age = 38.6 ± 1.2 weeks; five males) were recruited from the Children's Hospital of Chongqing Medical University neonatal ward. All subjects were scanned on identical 3 T Philips Achieva scanners equipped with an eight-channel SENSE head coil and underwent a multiecho gradient echo scan, a 32-direction DTI scan and a myelin water imaging scan. For both neonates and adults, bin-averaged R2* variation across the brain's white matter was found to be best explained by fibre orientation. For adults, this represented a difference in R2* values of 3.5 Hz from parallel to perpendicular fibres with respect to the main magnetic field. In neonates, the fibre orientation dependency displayed a cosine wave shape, with a small R2* range of 0.4 Hz. This minor relationship in neonates provides further evidence for the key role myelin probably plays in creating this fibre orientation dependence later in life, but suggests limited clinical application in newborn populations. Future studies should investigate fibre-orientation dependency in infants in the first 5 years, when substantial myelin development occurs.

Value of provocative electrophysiology testing in the management of pediatric patients after congenital heart surgery.

OBJECTIVE: To determine the impact of provocative electrophysiology testing in postoperative congenital heart disease (CHD) patients on the management of supraventricular tachycardia (SVT) and clinical outcomes. METHODS: This is a retrospective study including patients <18 years of age with surgery for CHD who had postoperative SVT between 2006 and 2017. Postoperative outcomes were compared between patients with and without postoperative electrophysiology testing using the Wilcoxon rank sum test, Fisher's exact test, Kaplan-Meier method with the log-rank test, and Cox proportional hazard model. RESULTS: From 341 patients who had SVT after surgery for CHD, 65 (19%) had postoperative electrophysiology testing. There was no significant difference in baseline patient characteristics or surgical complexity between patients with and without electrophysiology testing. Patients with inducible SVT on electrophysiology testing were more likely to have recurrence of SVT prior to hospital discharge with an odds ratio 4.0 (95% confidence interval 1.3, 12.0). Patients who underwent postoperative electrophysiology testing had shorter intensive care unit (12 [6, 20] vs 16 [9, 32] days, HR 2.1 [95% CI 1.6, 2.8], P < .001) and hospital (25 [13, 38] vs 31 [18, 54] days, HR 1.8 [95% CI 1.4, 2.4], P < .001) length of stay. CONCLUSION: Postoperative electrophysiology testing was associated with improved postoperative outcomes, likely related to the ability to predict recurrence of arrhythmia and tailored antiarrhythmic management.