Progressive QRS Duration and Ventricular Dysfunction in Pediatric Patients with Chronic Ventricular Pacing.

Pacemakers are a mainstay of therapy for patients with congenital and acquired heart block, but ventricular pacing is related to ventricular dysfunction. We sought to evaluate patient and device characteristics associated with ventricular dysfunction in pediatric patients with chronic ventricular pacing. This was a retrospective cohort of pediatric patients with heart block and chronic ventricular pacing. Patient, ECG, and device characteristics were analyzed to determine factors associated with ventricular dysfunction. Longitudinal ECG and echocardiogram parameters were obtained to track changes in QRS and systemic ventricular systolic function over time. In total, 82 patients were included (median age at implant 0.81 years). Over a follow-up time of 6.1 years, 18% developed ventricular dysfunction. Patients with dysfunction had greater current QRS duration (p = 0.002) compared to those with preserved function with a similar time from device implantation. There was no difference between lead location or age at device implantation. QRS duration increased with time from implant and the resultant ΔQRS was associated with ventricular dysfunction (p = 0.01). QRS duration >162 ms was associated with a 5.8 (2-9)-fold increased risk for dysfunction. Transvenous leads were associated with longer QRS duration with no difference compared to epicardial leads in development of ventricular dysfunction. This study demonstrated that the absolute paced QRS duration and Δpaced QRS were association with long-term ventricular dysfunction independent of how long a given patient was paced. Patients in high-risk categories may benefit from close echocardiographic monitoring. Whether permissive junctional rhythm or His bundle/biventricular pacing decreases the rate of dysfunction needs further study.

Can noninvasive testing identify benign patterns of suggested pre-excitation on electrocardiogram?

BACKGROUND: The presence of anterograde conduction through an accessory pathway (AP) has been linked to sudden cardiac death. Unfortunately, pre-excitation associated with classic pathways can be difficult to differentiate from benign APs such as nodofascicular fibers. OBJECTIVE: Identifying characteristics on electrocardiogram (ECG) and exercise that differentiate classic and benign AP connections in suggested pre-excitation patterns. METHODS: Retrospective review of patients presenting between 1995 and 2017 with ventricular pre-excitation on ECG, determined to have either typical left-lateral AP during electrophysiology study (EPS), or benign, or no AP determined by either transesophageal electrophysiology study (TEP), or EPS. RESULTS: A total of 96 patients were included, 14.2 years (4-24), 45% female, 90% Caucasian. Of these, 60 (63%) had a classic APs identified on EPS and 58 (97%) underwent successful ablation. Conversely, 36 (37%) had benign pathways identified. ECG findings differed between the groups: PR-interval 102 versus 120 ms (P < .0001), QRS-duration 110 versus 102 ms (P < .0001), QRS-axis 74 versus 59 degrees (P = .0005), and QRS onset to peak R/S in limb leads 64 versus 42 ms (P < .0001), and precordial leads 66 versus 46 ms (P < .0001). Change in QRS duration during exercise differed between the groups: 25 versus 2 ms (P < .0001) and ECG characteristics identified the presence of an AP with 97% sensitivity and 94% negative predictive value. CONCLUSION: Classic and benign APs exhibit different ECG characteristics, though clinical overlap does not allow for absolute differentiation. These data may help with risk stratification decision making though does not obviate the need for additional invasive testing.

Patient understanding of disease and the use and outcome of implantable cardioverter defibrillators in hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is the most common cause of sudden cardiac death (SCD) in young individuals. Implantable cardioverter defibrillators (ICD) are the primary therapy for sudden death prevention; however, are associated with both physical and psychological complications. We sought to determine factors associated with ICD understanding and patient satisfaction. This was a cross-sectional study, using patient/parent answered questionnaires distributed to patients enrolled in the Hypertrophic Cardiomyopathy Association. Patient characteristics and satisfaction data were obtained via questionnaire. Patients were compared based on age at diagnosis and presence of ICD. ICD patients with high satisfaction were compared to those with low satisfaction to determine factors associated with poor satisfaction. A total of 538 responses were obtained (53 ± 16 years); 46% were females. Seventy patients (13%) were diagnosed with HCM < 18 years of age and 356 (66%) had an ICD. Compared to those without an ICD, patients with ICDs were younger at age of diagnosis (P = 0.001) and time of study (P = 0.008). Patients with ICDs were more likely to have presented with syncope and have family history of ICD, SCD, or HCM-related death. Nineteen patients (5%) felt that issues surrounding their ICD outweighed its benefit. Compared to patients with a favorable satisfaction, the only significant difference was the preimplant ICD discussion (P < 0.001) and history of lead replacement (P = 0.01). In conclusion, the majority of HCM patients with ICDs are satisfied with their ICD management and feel the benefits of ICDs outweigh issues associated with ICDs. Additionally, these data highlight the importance of the preimplant patient-physician discussion around the need for ICD prior to implantation.

Risks and outcomes of direct current cardioversion in children and young adults with congenital heart disease.

OBJECTIVES: Evaluate the efficacy, outcomes, and complications associated with direct current cardioversion (DCCV) in the treatment of arrhythmias in pediatric and adult congenital heart disease (CHD) populations and identify patient and procedural characteristics associated with adverse events. BACKGROUND: Pediatric and adult patients with CHD are at risk of atrial arrhythmias. DCCV is effective but is associated with potential complications. METHODS: In this single-center retrospective series, patients who underwent DCCV between January 2010 and May 2015 were identified and categorized as pediatric (<18 years) or adult (> 18 years). Records were reviewed for demographic, arrhythmic, and CHD-specific characteristics; acute efficacy; and 3-month arrhythmia recurrence. Complications were categorized as life-threatening (LT) or non-life-threatening (NLT). Univariate followed by multiple variable and logistic regression (LR) analyses were used to identify characteristics associated with complications. RESULTS: We identified 104 patients with 152 discrete DCCV events with median age 17.4 years (0.15-62.2). DCCV efficacy was 89% with 3-month recurrence of 46%. There were 52 complications among 24 patients, median age 17.7 years (0.15-49). Risks associated with NLT complications are as follows: moderate-severe systolic dysfunction (8/152 encounters, P = < 0.01) and more than one shock per DCCV encounter (P = < 0.01). Six of eight encounters with moderate-severe systolic dysfunction were <18 years (P = 0.1). Risks for LT complications included age >18 years and associated NLT complication. Adults had more frequent arrhythmia recurrence within 3 months than children (P = < 0.01). CONCLUSIONS: DCCV is effective for arrhythmias but is associated with frequent recurrence, particularly in adult patients. Complications associated with DCCV may be greater than previously reported. Additional support and precautions should be in place for those at greatest risk.

Early Repolarization in Normal Adolescents is Common.

In adults with structurally normal hearts, the early repolarization pattern (ERP) on electrocardiogram (ECG) may be associated with an increased risk of sudden cardiac death. The prevalence and significance of the ERP in children is unknown. This study examines the prevalence of the ERP, the population in which it is found, and whether there exists any correlation with increased LV mass or family history of significant cardiac events. This was a secondary review of data obtained from healthy adolescents undergoing a limited ECG and transthoracic echocardiogram (TTE) as part of a cardiac screening study. Subjects were excluded if ECG revealed known arrhythmic syndromes or TTE revealed structural abnormalities. ERP was defined as (1) notching or slurring of the terminal QRS; (2) elevation of the QRS-ST junction ≥1 mV; and (3) upwardly concave positive T-wave. Left ventricular (LV) mass was defined as mass/height2.7. Patient demographics, LV mass, family history of sudden death, arrhythmia, and/or ICD/pacemaker placement were compared for subjects with and without ERP on ECG. Data from 575 subjects (median age 15, range 13-18; 36% female; 93% Caucasian) were reviewed. The incidence of ERP was 40% (n = 228) and was seen in the inferior, lateral, or combination of these leads in 42, 10, and 48% of subjects with ERP, respectively. There was no difference in gender (p = 0.7), race (p = 0.7), age (p = 0.3), history of syncope (p = 0.2), LV mass (p = 0.8), family history of (a) sudden death (p = 0.5), (b) arrhythmia (p = 0.2), or (c) ICD/pacemaker requirement (p = 0.8) in subjects with ERP versus those without. However, a greater percentage of patients with ERP were noted to play football, when compared to those without ERP (34 vs. 13%, p < 0.001). ERP is common in healthy adolescents, and does not correlate with concerning personal/family history or elevated LV mass. Longitudinal studies are required to determine whether ERP in childhood confers an increased mortality risk.

Arrhythmic Burden and Ambulatory Monitoring of Pediatric Patients with Cardiomyopathy.

BACKGROUND: Pediatric patients with cardiomyopathy (CM) are at risk for sudden cardiac death (SCD), likely driven by arrhythmic etiologies. OBJECTIVES: Describe arrhythmia burden and Holter utility in pediatric CM including: hypertrophic CM (HCM), dilated CM (DCM), and restrictive CM (RCM). METHODS: Retrospective cohort study of patients <21 years with CM. Patient demographics, arrhythmic history, and genetic status were reviewed including outcomes of death, aborted SCD, and device shocks. Holter findings were analyzed over the prior 5 years including clinically significant findings and resulting changes to management. Analysis for the composite outcomes of death, aborted SCD, and appropriate shock were performed using logistic regression with backward elimination. RESULTS: One hundred and forty-six patients were included: 83 HCM, 54 DCM, and nine RCM (mean 13 ± 6 years). A total of 23% of patients had defibrillators. There were six deaths (two SCD), four patients with appropriate device therapies, and four aborted SCD episodes. In total, 305 Holter monitors were reviewed. Six Holters had significant findings, all nonsustained ventricular tachycardia. Two Holters resulted in changes in management, both defibrillator implantations. Twelve patients had one or more of the conditions defining the composite outcome. Using logistic regression, clinical history of ventricular arrhythmia, frequent premature ventricular complexes, and CM type were included as potential independent predictors in the final model and clinical ventricular arrhythmia and RCM disease were associated with the composite outcome. CONCLUSIONS: SCD and device therapies were relatively rare. Routine Holter screening rarely demonstrated significant findings or changed clinical care. Clinical history of ventricular arrhythmia was associated with poor clinical outcome.

Electrocardiography Screening for Hypertrophic Cardiomyopathy.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is the leading cause of sudden cardiac death in athletes. However, preparticipation electrocardiogram (ECG) screening has been criticized for failing to meet cost-effectiveness thresholds, in part because of high false-positive rates. We sought to evaluate whether a highly automated software algorithm could be used for a high throughput, population-based screening program and address several of the limitations seen with population-based screening METHODS: A proprietary computed algorithm was created based on both voltage- as well as Seattle-based ECG criteria. Different cut points for Q-wave depth, Q-wave length, the degree of ST depression, the degree of T-wave inversion, and left ventricular voltage were analyzed for optimum sensitivity and specificity. After developing receiver operating characteristic curves for each criterion, different cut points were trialed together on our data set to obtain settings to optimize sensitivity and specificity. RESULTS: The automated algorithm was capable of identifying patients with HCM based on ECG with 88.6% sensitivity and 98% specificity, compared to a sensitivity of 90.2% and specificity of 96% when the ECGs were read by physicians according to the Seattle Criteria. Adding voltage criteria improved the sensitivity of the algorithm with a mild decrease in specificity. Optimum sensitivity with this automated software was 98%; optimum specificity was 96%. CONCLUSION: Computer-automated ECG screening for HCM is feasible. Evaluation of automated ECG algorithms in larger and more diverse populations is warranted.

Variation in Antiarrhythmic Management of Infants Hospitalized with Supraventricular Tachycardia: A Multi-Institutional Analysis.

Supraventricular tachycardia (SVT) is the most frequent form of symptomatic tachyarrhythmia in infants. The purposes of this study were to describe practice patterns of the management of infants hospitalized with SVT and factors associated with 30-day hospital readmission. This was a multi-institutional, retrospective review of the pediatric health information system database of SVT hospitalizations from 2003 to 2013. High-volume centers (HVC) were defined as those at the upper quartile of admissions. Infants with an ICD-9 code of paroxysmal SVT were included. Antiarrhythmics investigated included amiodarone, atenolol, digoxin, esmolol, flecainide, procainamide, propafenone, propranolol, and sotalol. Frequency of antiarrhythmic use based on center volume was the primary end point. Rate of 30-day SVT readmission was the secondary end point. Analysis of factors associated with readmission was assessed by Chi-square analysis and expressed as odds ratio and 95 % confidence interval. A total of 851 patients (60 % male, 44 % neonates) were hospitalized at 43 hospitals. Propranolol, digoxin, and amiodarone were the most frequently utilized antiarrhythmics. HVCs represented 12 hospitals comprising 494 (58 %) patients. Although HVCs were more likely to utilize propranolol (OR 2.5, CI 1.5-4.1), there was no significant difference in the 30-day readmission rate between patients treated at HVCs versus non-HVCs (p = 0.9). The majority of infants with SVT are treated with a small number of antiarrhythmic medications during index hospitalization. Although hospital-to-hospital variation in antiarrhythmic choice exists, there appears to be no difference in readmission. The remaining practice variation may be related to intrinsic patient characteristics.

Critical care for patients with congenital abnormalities of the coronary arteries.

Congenital abnormalities of the coronary arteries in the absence of structural heart disease account for a small but interesting percentage of cardiac lesions in children. Their presentation may vary from incidental identification to aborted/sudden cardiac death. Patients with aborted sudden death episodes will require significant support if they develop extensive ischaemic myocardial injury. Ultimately, surgical repair should be carried out as soon as haemodynamic stability is attained and the neurological status is evaluated. The aims of this article were to provide a review of congenital abnormalities of the coronary arteries most commonly seen in children in the ICU as well as to review the current critical-care management thereof.

Relationship between echocardiographic LV mass and ECG based left ventricular voltages in an adolescent population: related or random?

BACKGROUND: In attempts to detect diseases that may place adolescents at risk for sudden death, some have advocated for population-based screening. Controversy exists over electrocardiography (ECG) screening due to the lack of specificity, cost, and detrimental effects of false positive or extraneous outcomes. OBJECTIVES: Analyze the relationship between precordial lead voltage on ECG and left ventricle (LV) mass by echocardiogram in adolescent athletes. METHODS: Retrospective cohort analysis of a prospectively obtained population of self-identified adolescent athletes during sports screening with ECG and echocardiogram. Correlation between ECG LV voltages (R wave in V6 [RV6] and S wave in lead V1 [SV1]) was compared to echocardiogram-based measurements of left ventricular mass. Potential effects on ECG voltages by body anthropometrics, including weight, body mass index (BMI), and body surface area were analyzed, and ECG voltages indexed to BMI were compared to LV mass indices to analyze for improved correlation. RESULTS: A total of 659 adolescents enrolled in this study (64% male). The mean age was 15.4 years (14-18). The correlations between LV mass and RV6, SV1, and RV6 + SV1 were all less than 0.20. The false positive rate for abnormal voltages was relatively high (5.5%) but improved if abnormal voltages in both RV6 and SV1 were mandated simultaneously (0%). Indexing ECG voltages to BMI significantly improved correlation to LV mass, though false positive findings were increased (12.9%). CONCLUSION: There is poor correlation between ECG precordial voltages and echocardiographic LV mass. This relationship is modified by BMI. This finding may contribute to the poor ECG screening characteristics.

Atrial Standstill in the Pediatric Population: A Multi-Institution Collaboration.

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.

Postoperative heart block in children with common forms of congenital heart disease: results from the KID Database.

INTRODUCTION: Cardiac conduction system injury is a cause of postoperative cardiac morbidity following repair of congenital heart disease (CHD). The national occurrence of postoperative complete heart block (CHB) following surgical repair of CHD is unknown. We sought to describe the occurrence of and costs related to postoperative CHB following surgical repair of common forms of CHD using a large national database. METHODS AND RESULTS: Retrospective, observational analysis performed over a 10-year period (2000-2009) using the Kids' Inpatient Database (KID). Visits for patients ≤24 months of age were identified who underwent surgical repair of ventricular septal defects (VSD), atrioventricular canal defects (AVC), and tetralogy of Fallot (TOF). Patients were identified who were diagnosed with postoperative CHB, further identifying those requiring a new pacemaker placement during the same hospitalization. Costs associated with visits were calculated. There were 16,105 surgical visits: 7,146 VSD, 3,480 AVC, and 5,480 TOF. There was a decrease in postoperative mortality (P = 0.0001) with no significant change in postoperative CHB. Hospital stay and cost were higher with CHB and placement of a permanent pacemaker. Repair of AVC (OR 1.77; [1.32-2.38]) was associated with a higher rate of postoperative CHB. Length of hospital stay and total cost were significantly increased with the development of postoperative CHB and increased further with placement of a permanent pacemaker. CONCLUSION: There has been little change over time in the frequency of postoperative CHB in patients undergoing repair of VSD, AVC, and TOF. Postoperative CHB results in major added cost to the healthcare system.

The effect of paediatric syncope on health-related quality of life.

BACKGROUND: Syncope is common in children and adolescents and most commonly represents neurocardiogenic syncope. No information has been reported regarding the effect of syncope on health-related quality of life in children. METHODS: This was a retrospective cohort study of patients seen in the Heart Institute Syncope Clinic at Cincinnati Children's Hospital Medical Center between July, 2009 and June, 2010. Health-related quality of life was assessed using the PedsQL™ tool. PedsQL™ scores were compared with both healthy historical controls and historical controls with chronic illnesses. RESULTS: A total of 106 patients were included for analysis. In all, 90% were Caucasian and 63% were girls. The median age was 15.1 years (8.2-21.6). Compared with healthy controls, patients had lower PedsQL™ scores: Total score (75.2 versus 83.8, p < 0.0001); Physical Health Summary (78.8 versus 87.5, p < 0.0001); Psychosocial Health Summary (73.9 versus 81.9, p < 0.001), Emotional Functioning (68.9 versus 79.3, p < 0.001); and School Functioning (66.4 versus 81.1, p < 0.001). No difference was seen in Social Functioning (86.2 versus 85.2, p = 0.81). Patients also had lower PedsQL™ Total scores than patients with diabetes mellitus (p < 0.0001) and similar scores to patients with asthma, end-stage renal disease, obesity, and structural heart disease. CONCLUSION: Children with syncope, although typically benign in aetiology, can have low health-related quality of life.

Pediatric syncope: National Hospital Ambulatory Medical Care Survey results.

BACKGROUND: Syncope is a common problem in children and adolescents. The diagnostic yield for most tests commonly used in the evaluation of pediatric patients with syncope is low. STUDY OBJECTIVE: To examine the epidemiology of pediatric patients presenting to United States (US) emergency departments (EDs) with a complaint of syncope and compare their initial management to published guidelines. METHODS: ED visits from the National Hospital Ambulatory Medical Care Survey for 2003-2007 for patients aged 7-18 years were analyzed. Outcome variables were diagnostic tests and management of patients presenting with syncope. RESULTS: There were 627,489 (95% confidence interval [CI] 527,237-727,722) ED visits for syncope (0.9% of all ED visits for patients aged 7-18 years). Patients presenting to the ED for syncope were more commonly female (p<0.01), adolescent (13-18 years) (p<0.01), covered by private insurance (p=0.01), and more likely to arrive to the ED by ambulance (p<0.01), compared to those presenting with other complaints. Only 58.1% (95% CI 50.3-66.0%) of syncope patients received an electrocardiogram, and 26.5% (95% CI 18.2-34.7%) received a computed tomography (CT) or magnetic resonance imaging (MRI) scan as part of their diagnostic work-up. CONCLUSIONS: When evaluating pediatric patients presenting with syncope, there should be an increased use of the electrocardiogram to screen for underlying cardiac abnormalities. There should also be a tempered use of CT/MRI imaging in this population.

Off-Label Prescription of COVID-19 Vaccines in Children: Clinical, Ethical, and Legal Issues.

The US Food and Drug Administration (FDA) approval of the biologics license application for the Pfizer-BioNTech coronavirus disease 2019 vaccine (Comirnaty) on August 23, 2021, opened the door to the off-label vaccination of children younger than the age range currently covered by either the biologics license application (16 years old and older) or the emergency use authorization (12 to 15 years old). Although prescribing medications at doses, for conditions, or in populations other than those approved by the FDA is generally legal and is common in pediatrics, the FDA, the Centers for Disease Control and Prevention, and the American Academy of Pediatrics have recommended against off-label prescription of the coronavirus disease 2019 vaccine. Several commentaries consider a case in which parents ask their child's pediatrician to prescribe the vaccine for their 11-year-old with special health care needs before approval or authorization in her age group. The first commentary considers the potential benefits and risks to the patient, as well as to the family, the provider, and society, emphasizing the unknown risks in younger patients and the need for adequate informed consent. The second commentary describes an algorithm and principles for evaluating off-label prescribing and argues that the current benefits of prescribing Comirnaty off label to children <12 do not outweigh the risks. The third commentary addresses ethical and legal issues, ultimately calling on federal agencies to remove legal barriers to making the vaccine available to children in age groups that currently lack authorization.

Arrhythmia Burden and Heart Rate Response During Exercise in Anderson-Fabry Disease.

Patients with Anderson-Fabry disease (AFD) have an elevated incidence of resting arrhythmias and ischemic heart disease, but their exercise arrhythmia burden and ischemic changes are not well understood. In addition, little research has been done on heart rate recovery in these patients. We retrospectively reviewed charts of patients with AFD who underwent maximal effort cardiopulmonary exercise testing (CPET) (n=44; 38.2 ± 13.8 yr; 23 men) from 2012 through 2018. Electrocardiographic, Holter monitoring, echocardiographic, cardiac magnetic resonance imaging, and patient demographic data were collected. No patient had adverse events that necessitated CPET termination, whereas 25 (57%) had ectopy during CPET, including 3 (7%) with frequent premature atrial contractions and 5 (11%) with frequent premature ventricular contractions. The ectopic burden was higher during resting electrocardiographic monitoring before exercise. In addition, 7 patients (16%) had pathologic ST-segment or T-wave changes on CPET, defined as ST-segment changes ≥2 mm. Among the patients who had concurrent cardiac magnetic resonance findings with their CPET (n=27), ST-segment or T-wave changes were associated with left ventricular myocardial mass (r=0.43, P=0.02). Chronotropic incompetence was seen during CPET in 28 patients (64%); however, only 2 patients (4%) had abnormal heart rate recovery at 1 minute. This study shows that patients with AFD can safely undergo exercise testing but have a high incidence of exercise-induced arrhythmias and ischemic changes. Ischemic electrocardiographic changes during exercise testing are associated with myocardial mass. Despite the chronotropic incompetence associated with AFD, heart rate recovery appears to be generally preserved in these patients.

Noninvasive risk stratification techniques in pediatric patients with ventricular preexcitation.

BACKGROUND: Individuals with ventricular preexcitation (VP) are known to have an increased risk of sudden death. This risk has been associated with conduction properties of the accessory pathway. METHODS: Patients with VP underwent risk stratification through the use of exercise and transesophageal testing. All patients were initially screened with exercise testing and those with preexcitation throughout exercise went on to have transesophageal testing. Patients who demonstrated high-risk pathway characteristics by transesophageal testing or developed clinical indications for an electrophysiology (EP) study underwent ablation. This stepwise risk stratification technique was evaluated for the ability to avoid the need for intracardiac EP study. Patients stratified as low risk were contacted for follow-up. RESULTS: One hundred and twenty-nine exercise studies were performed in 127 patients. Thirty-five of 129 exercise studies demonstrated accessory pathway block during exercise. Twenty-seven of 35 underwent no additional testing. Sixty-six patients underwent transesophageal testing. Forty-nine of 66 patients demonstrated low-risk pathway characteristics and 40 of 49 underwent no further testing. In total, 68 of 129 (53%) patients avoided the need for intracardiac EP study and ablation. A noncardiac indication for the initial diagnostic electrocardiogram was associated with lower likelihood of intracardiac EP study. None of the patients stratified as low risk had additional invasive procedures or life-threatening arrhythmias upon follow-up. CONCLUSIONS: Successful risk stratification of pediatric patients with VP is possible through the use of exercise and transesophageal testing. In this patient population, half of the patients were able to avoid an intracardiac EP study.

Outcomes of Implantable Loop Monitoring in Patients <21 Years of Age.

Rhythm-symptom correlation in pediatric patients with syncope/palpitations or at risk cohorts can be difficult, but important given potential associations with treatable or malignant arrhythmia. We sought to evaluate the use, efficacy and outcomes of implantable loop recorders (ILR) in pediatrics. We conducted a retrospective study of pediatric patients (<21 years) with implanted ILR. Patient/historical characteristics and ILR indication were obtained. Outcomes including symptom documentation, arrhythmia detection and ILR based changes in medical care were identified. Comparison of outcomes were performed based on implant indication. Additional sub-analyses were performed in syncope-indication patients comparing those with and without changes in clinical management. A total of 116 patients with ILR implant were identified (79 syncope/37 other). Symptoms were documented 58% of patients (syncope 68% vs nonsyncope 35%; p = 0.002). A total of 37% of patients had a documented clinically significant arrhythmia and 25% of patients had a resultant change in clinical management independent of implant indication. Arrhythmia type was dependent on implant indication with nonsyncope patients having more ventricular arrhythmias. Pacemaker/defibrillator implantation and mediation management were the majority of the clinical changes. In conclusion, IRL utilization in selected pediatric populations is associated with high efficacy and supports clinical management. ILR efficacy is similar regardless of indication although patients with nonsyncope indications had a higher frequency of ventricular arrhythmias as opposed to asystole and heart block in syncope indications. The majority of arrhythmic findings occurred in the first 12 months, and new technology that would allow for less invasive monitoring for 6 to 12 months may be of value.

Updated International Tuberous Sclerosis Complex Diagnostic Criteria and Surveillance and Management Recommendations.

BACKGROUND: Tuberous sclerosis complex (TSC) is an autosomal dominant genetic disease affecting multiple body systems with wide variability in presentation. In 2013, Pediatric Neurology published articles outlining updated diagnostic criteria and recommendations for surveillance and management of disease manifestations. Advances in knowledge and approvals of new therapies necessitated a revision of those criteria and recommendations. METHODS: Chairs and working group cochairs from the 2012 International TSC Consensus Group were invited to meet face-to-face over two days at the 2018 World TSC Conference on July 25 and 26 in Dallas, TX, USA. Before the meeting, working group cochairs worked with group members via e-mail and telephone to (1) review TSC literature since the 2013 publication, (2) confirm or amend prior recommendations, and (3) provide new recommendations as required. RESULTS: Only two changes were made to clinical diagnostic criteria reported in 2013: "multiple cortical tubers and/or radial migration lines" replaced the more general term "cortical dysplasias," and sclerotic bone lesions were reinstated as a minor criterion. Genetic diagnostic criteria were reaffirmed, including highlighting recent findings that some individuals with TSC are genetically mosaic for variants in TSC1 or TSC2. Changes to surveillance and management criteria largely reflected increased emphasis on early screening for electroencephalographic abnormalities, enhanced surveillance and management of TSC-associated neuropsychiatric disorders, and new medication approvals. CONCLUSIONS: Updated TSC diagnostic criteria and surveillance and management recommendations presented here should provide an improved framework for optimal care of those living with TSC and their families.