Characterization and Management of Arrhythmic Events in Young Patients With Brugada Syndrome

Inherited Arrhythmias in the Pediatric Population: An Updated Overview

Pediatric cardiomyopathies (CMs) and electrical diseases constitute a heterogeneous spectrum of disorders distinguished by structural and electrical abnormalities in the heart muscle, attributed to a genetic variant. They rank among the main causes of morbidity and mortality in the pediatric population, with an annual incidence of 1.1-1.5 per 100,000 in children under the age of 18. The most common conditions are dilated cardiomyopathy (DCM) and hypertrophic cardiomyopathy (HCM). Despite great enthusiasm for research in this field, studies in this population are still limited, and the management and treatment often follow adult recommendations, which have significantly more data on treatment benefits. Although adult and pediatric cardiac diseases share similar morphological and clinical manifestations, their outcomes significantly differ. This review summarizes the latest evidence on genetics, clinical characteristics, management, and updated outcomes of primary pediatric CMs and electrical diseases, including DCM, HCM, arrhythmogenic right ventricular cardiomyopathy (ARVC), Brugada syndrome (BrS), catecholaminergic polymorphic ventricular tachycardia (CPVT), long QT syndrome (LQTS), and short QT syndrome (SQTS).

Characterisation and long-term follow-up of children with Brugada syndrome: experience from a tertiary paediatric referral centre

AIMS

Brugada syndrome is an inherited condition, which typically presents in young adults. It can also be diagnosed in children, but data in this group remain scarce. This study aims to describe the clinical features, management, and follow-up of children with personal or family history of Brugada syndrome.

METHODS

Retrospective study of consecutive patients with Brugada history followed up in a tertiary paediatric referral centre between 2009 and 2021. Patients were assessed according to the phenotype: positive (with variable genotype) or negative (with positive genotype).

RESULTS

Thirty patients were included (mean age at diagnosis 7 ± 6 years, 53% male). Within the positive phenotype (n = 16), 81% were male, and 88% had spontaneous type 1 ECG pattern. A genetic test was performed in 88% and was positive in 57%. Fourteen patients had a negative phenotype-positive genotype, 79% female, all diagnosed during family screening; 43% mentioned family history of sudden cardiac death. Although most of the patients were asymptomatic, the prevalence of rhythm/conduction disturbances was not negligible, particularly if a positive phenotype. No clinically significant events were reported in the negative phenotype patients. Three patients were hospitalised due to an arrhythmic cause, all in patients with a positive phenotype.

CONCLUSION

In our study, the documentation of rhythm and conduction disturbances was not infrequent, especially in patients with a positive phenotype. Despite the significant family history, phenotype negative patients had no relevant events during follow-up. Nevertheless, the management of these patients is not clear cut, and a personalised therapeutic strategy with close follow-up is essential.

Ethnic and racial differences in Asian populations with ion channelopathies associated with sudden cardiac death

Cardiovascular diseases are associated with several morbidities and are the most common cause of worldwide disease-related fatalities. Studies show that treatment and outcome-related differences for cardiovascular diseases disproportionately affect minorities in the United States. The emergence of ethnic and racial differences in sudden cardiac death (SCD) and related ion channelopathies complicates cardiovascular disease prevention, diagnosis, management, prognosis, and treatment objectives for patients and physicians alike. This review compiles and synthesizes current research in cardiac ion channelopathies and genetic disorders in Asian populations, an underrepresented population in cardiovascular literature. We first present a brief introduction to SCD, noting relevant observations and statistics from around the world, including Asian populations. We then examined existing differences between Asian and White populations in research, treatment, and outcomes related to cardiac ion channelopathies and SCD, showing progression in thought and research over time for each ion channelopathy. The review also identifies research that explored phenotypic abnormalities, device usage, and risk of death in Asian patients. We touch upon the unique genetic risk factors in Asian populations that lead to cardiac ion channelopathies and SCD while comparing them to White and Western populations, particularly in the United States, where Asians comprise approximately 7% of the total population. We also propose potential solutions such as improving early genetic screening, addressing barriers affecting access to medical care and device utilization, physician training, and patient education on risks.

Genetic testing in children with Brugada syndrome: results from a large prospective registry

AIMS

A pathogenic/likely pathogenic (P/LP) variant in SCN5A is found in 20-25% of patients with Brugada syndrome (BrS). However, the diagnostic yield and prognosis of gene panel testing in paediatric BrS is unclear. The aim of this study is to define the diagnostic yield and outcomes of SCN5A gene testing with ACMG variant classification in paediatric BrS patients compared with adults.

METHODS AND RESULTS

All consecutive patients diagnosed with BrS, between 1992 and 2022, were prospectively enrolled in the UZ Brussel BrS registry. Inclusion criteria were: (i) BrS diagnosis; (ii) genetic analysis performed with a large gene panel; and (iii) classification of gene variants following ACMG guidelines. Paediatric patients were defined as ≤16 years of age. The primary endpoint was ventricular arrhythmias (VAs). A total of 500 BrS patients were included, with 63 paediatric patients and 437 adult patients. Among children with BrS, 29 patients (46%) had a P/LP variant (P+) in SCN5A and no variants were found in 34 (54%) patients (P-). After a mean follow-up of 125.9 months, 8 children (12.7%) experienced a VA, treated with implanted cardioverter defibrillator shock. At survival analysis, P- paediatric patients had higher VA-free survival during the follow-up, compared with P+ paediatric patients. P+ status was an independent predictor of VA. There was no difference in VA-free survival between paediatric and adult BrS patients for both P- and P+.

CONCLUSION

In a large BrS cohort, the diagnostic yield for P/LP variants in the paediatric population is 46%. P+ children with BrS have a worse arrhythmic prognosis.

Screening, diagnosis and follow-up of Brugada syndrome in children: a Dutch expert consensus statement

Brugada syndrome (BrS) is a rare inherited arrhythmia syndrome. Affected children may experience life-threatening symptoms, mainly during fever. The percentage of SCN5A variant carriers in children is higher than in adults. Current diagnostic and follow-up policies for children with (a family history of) BrS vary between centres. Here, we present a consensus statement based on the current literature and expert opinions to standardise the approach for all children with BrS and those from BrS families in the Netherlands. In summary, BrS is diagnosed in patients with a spontaneous type 1 electrocardiogram (ECG) pattern or with a Shanghai score ≥ 3.5 including ≥ 1 ECG finding. A sodium channel-blocking drug challenge test should only be performed after puberty with a few exceptions. A fever ECG is indicated in children with suspected BrS, in children with a first-degree family member with definite or possible BrS according to the Shanghai criteria with a SCN5A variant and in paediatric SCN5A variant carriers. In-hospital rhythm monitoring during fever is indicated in patients with an existing type 1 ECG pattern and in those who develop such a pattern. Genetic testing should be restricted to SCN5A. Children with BrS and children who carry an SCN5A variant should avoid medication listed at www.brugadadrugs.org and fever should be suppressed. Ventricular arrhythmias or electrical storms should be treated with isoproterenol infusion.

Investigation of High-Risk Electrocardiographic Markers as Predictors of Major Arrhythmic Events in Brugada Syndrome: A Systematic Review and Meta-analysis

INTRODUCTION

Numerous studies have demonstrated that a type I Brugada electrocardiographic (ECG) pattern, history of syncope, prior sudden cardiac arrest, and previously documented ventricular tachyarrhythmias are still insufficient to stratify the risk of sudden cardiac death in Brugada syndrome (BrS). Several auxiliary risk stratification parameters are pursued to yield a better prognostic model. Our aim was to assess the association between several ECG markers (wide QRS, fragmented QRS, S-wave in lead I, aVR sign, early repolarization pattern in inferolateral leads, and repolarization dispersion pattern) with the risk of developing poor outcomes in BrS.

METHODS

A systematic literature search from several databases was conducted from database inception until August 17^th, 2022. Studies were eligible if it investigated the relationship between the ECG markers with the likelihood of acquiring major arrhythmic events (MAE).

RESULTS

This meta-analysis comprised 27 studies with a total of 6552 participants. Our study revealed that wide QRS, fragmented QRS, S-wave in lead I, aVR sign, early repolarization pattern in inferolateral leads, and repolarization dispersion ECG pattern were associated with the incremental risk of syncope, ventricular tachyarrhythmias, implantable cardioverter-defibrillator shock, and sudden cardiac death in the future, with the risk ratios ranging from 1.41 to 2.00. Moreover, diagnostic test accuracy meta-analysis indicated that the repolarization dispersion ECG pattern had the highest overall area under curve (AUC) value amid other ECG markers regarding our outcomes of interest.

CONCLUSION

A multivariable risk assessment approach based on the prior mentioned ECG markers potentially improves the current risk stratification models in BrS patients.

Risk stratification of sudden cardiac death in asymptomatic female Brugada syndrome patients: A literature review

BACKGROUND AND OBJECTIVES

Risk stratification in Brugada syndrome remains a difficult problem. Given the male predominance of this disease and their elevated risks of arrhythmic events, affected females have received less attention. It is widely known that symptomatic patients are at increased risk of sudden cardiac death (SCD) than asymptomatic patients, while this might be true in the male population; recent studies have shown that this association might not be significant in females. Over the past few decades, numerous markers involving clinical symptoms, electrocardiographic (ECG) indices, and genetic tests have been explored, with several risk-scoring models developed so far. The objective of this study is to review the current evidence of clinical and ECG markers as well as risk scores on asymptomatic females with Brugada syndrome.

FINDINGS

Gender differences in ECG markers, the yield of genetic findings, and the applicability of risk scores are highlighted.

CONCLUSIONS

Various clinical, electrocardiographic, and genetic risk factors are available for assessing SCD risk amongst asymptomatic female BrS patients. However, due to the significant gender discrepancy in BrS, the SCD risk amongst females is often underestimated, and there is a lack of research on female-specific risk factors and multiparametric risk scores. Therefore, multinational studies pooling female BrS patients are needed for the development of a gender-specific risk stratification approach amongst asymptomatic BrS patients.

Comparing the performance of published risk scores in Brugada syndrome: a multi-center cohort study

INTRODUCTION

The management of Brugada Syndrome (BrS) patients at intermediate risk of arrhythmic events remains controversial. The present study evaluated the predictive performance of different risk scores in an Asian BrS population and its intermediate risk subgroup.

METHODS

This retrospective cohort study included consecutive patients diagnosed with BrS from January 1^st, 1997 to June 20^th, 2020 from Hong Kong. The primary outcome is sustained ventricular tachyarrhythmias. Two novel risk risk scores and seven machine learning-based models (random survival forest, Ada boost classifier, Gaussian naïve Bayes, light gradient boosting machine, random forest classifier, gradient boosting classifier and decision tree classifier) were developed. The area under the receiver operator characteristic (ROC) curve (AUC) [95% confidence intervals] was compared between the different models.

RESULTS

This study included 548 consecutive BrS patients (7% female, age at diagnosis: 50±16 years, follow-up: 84±55 months). For the whole cohort, the score developed by Sieira et al. showed the best performance (AUC: 0.806 [0.747-0.865]). A novel risk score was developed using the Sieira score and additional variables significant on univariable Cox regression (AUC: 0.855 [0.808-0.901]). A simpler score based on non-invasive results only showed a statistically comparable AUC (0.784 [0.724-0.845]), improved using random survival forests (AUC: 0.942 [0.913-0.964]). For the intermediate risk subgroup (N=274), a gradient boosting classifier model showed the best performance (AUC: 0.814 [0.791-0.832]).

CONCLUSION

A simple risk score based on clinical and electrocardiographic variables showed a good performance for predicting VT/VF, improved using machine learning. Abstract: The management of Brugada Syndrome (BrS) patients at intermediate risk of arrhythmic events remains controversial. This study evaluated the predictive performance of published risk scores in a cohort of BrS patients from Hong Kong (N=548) and its intermediate risk subgroup (N=274). A novel risk score developed by modifying the best performing existing score (by. Sieira et al.) showed an area under the curve of 0.855 and 0.760 for the whole BrS cohort and the intermediate risk subgroup, respectively. The performance of the different scores was significantly improved machine learning-based methods, such as random survival forests and gradient boosting classifier.

Electrocardiographic Markers Indicating Right Ventricular Outflow Tract Conduction Delay as a Predictor of Major Arrhythmic Events in Patients With Brugada Syndrome: A Systematic Review and Meta-Analysis

Introduction

Risk stratification in Brugada Syndrome (BrS) patients is still challenging due to the heterogeneity of clinical presentation; thus, some additional risk markers are needed. Several studies investigating the association between RVOT conduction delay sign on electrocardiography (ECG) and major arrhythmic events (MAE) in BrS patients showed inconclusive results. This meta-analysis aims to evaluate the association between RVOT conduction delay signs presented by aVR sign and large S wave in lead I, and MAE in BrS patients.

Methods

The literature search was performed using several online databases from the inception to March 16th, 2022. We included studies consisting of two main components, including ECG markers of RVOT conduction delay (aVR sign and large S wave in lead I) and MAE related to BrS (syncope/VT/VF/SCD/aborted SCD/appropriate ICD shocks)

Results

Meta-analysis of eleven cohort studies with a total of 2,575 participants showed RVOT conduction delay sign was significantly associated with MAE in BrS patients [RR = 1.87 (1.35, 2.58); p < 0.001; I2= 52%, Pheterogeneity = 0.02]. Subgroup analysis showed that aVR sign [RR = 2.00 (1.42, 2.83); p < 0.001; I2= 0%, Pheterogeneity = 0.40] and large S wave in lead I [RR = 1.74 (1.11, 2.71); p = 0.01; I2= 60%, Pheterogeneity = 0.01] were significantly associated with MAE. Summary receiver operating characteristics analysis revealed the aVR sign [AUC: 0.77 (0.73–0.80)] and large S wave in lead I [AUC: 0.69 (0.65–0.73)] were a good predictor of MAE in BrS patients.

Conclusion

RVOT conduction delay sign, presented by aVR sign and large S wave in the lead I, is significantly associated with an increased risk of MAE in BrS patients. Hence, we propose that these parameters may be useful as an additional risk stratification tool to predict MAE in BrS patients.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/#recordDetails, identifier: CRD42022321090.

Brugada Syndrome in Women: What Do We Know After 30 Years?

Brugada syndrome (BrS) was initially described in 1992 by Josep and Pedro Brugada as an arrhythmogenic disease characterized by ST segment elevation in the right precordial leads and increased risk of sudden cardiac death (SCD). Alterations in the SCN5A gene are responsible for approximately 30% of cases of BrS, following an autosomal dominant pattern of inheritance. However, despite its autosomal transmission, sex-related differences are widely accepted. BrS is more prevalent in males than in females (8–10 times), with males having a 5.5-fold higher risk of SCD. There are also differences in clinical presentation, with females being more frequently asymptomatic and older than males at the time of diagnosis. Some factors have been identified that could explain these differences, among which testosterone seems to play an important role. However, only 30% of the available publications on the syndrome include sex-related information. Therefore, current findings on BrS are based on studies conducted mainly in male population, despite the wide acceptance of gender differences. The inclusion of complete clinical and demographic information in future publications would allow a better understanding of the phenotypic variability of BrS in different age and sex groups helping to improve the diagnosis, management and risk management of SCD.

Brugada Syndrome

Brugada syndrome (BrS) is an "inherited" condition characterized by predisposition to syncope and cardiac arrest, predominantly during sleep. The prevalence is ∼1:2,000, and is more commonly diagnosed in young to middle-aged males, although patient sex does not appear to impact prognosis. Despite the perception of BrS being an inherited arrhythmia syndrome, most cases are not associated with a single causative gene variant. Electrocardiogram (ECG) findings support variable extent of depolarization and repolarization changes, with coved ST-segment elevation ≥2 mm and a negative T-wave in the right precordial leads. These ECG changes are often intermittent, and may be provoked by fever or sodium channel blocker challenge. Growing evidence from cardiac imaging, epicardial ablation, and pathology studies suggests the presence of an epicardial arrhythmic substrate within the right ventricular outflow tract. Risk stratification aims to identify those who are at increased risk of sudden cardiac death, with well-established factors being the presence of spontaneous ECG changes and a history of cardiac arrest or cardiogenic syncope. Current management involves conservative measures in asymptomatic patients, including fever management and drug avoidance. Symptomatic patients typically undergo implantable cardioverter defibrillator insertion, with quinidine and epicardial ablation used for patients with recurrent arrhythmia. This review summarizes our current understanding of BrS and provides clinicians with a practical approach to diagnosis and management.

Clinical Genetics of Inherited Arrhythmogenic Disease in the Pediatric Population

Sudden death is a rare event in the pediatric population but with a social shock due to its presentation as the first symptom in previously healthy children. Comprehensive autopsy in pediatric cases identify an inconclusive cause in 40-50% of cases. In such cases, a diagnosis of sudden arrhythmic death syndrome is suggested as the main potential cause of death. Molecular autopsy identifies nearly 30% of cases under 16 years of age carrying a pathogenic/potentially pathogenic alteration in genes associated with any inherited arrhythmogenic disease. In the last few years, despite the increasing rate of post-mortem genetic diagnosis, many families still remain without a conclusive genetic cause of the unexpected death. Current challenges in genetic diagnosis are the establishment of a correct genotype-phenotype association between genes and inherited arrhythmogenic disease, as well as the classification of variants of uncertain significance. In this review, we provide an update on the state of the art in the genetic diagnosis of inherited arrhythmogenic disease in the pediatric population. We focus on emerging publications on gene curation for genotype-phenotype associations, cases of genetic overlap and advances in the classification of variants of uncertain significance. Our goal is to facilitate the translation of genetic diagnosis to the clinical area, helping risk stratification, treatment and the genetic counselling of families.

Risk of sports-related sudden cardiac death in women

Sudden cardiac death (SCD) is a tragic incident accountable for up to 50% of deaths from cardiovascular disease. Sports-related SCD (SrSCD) is a phenomenon which has previously been associated with both competitive and recreational sport activities. SrSCD has been found to occur 5-33-fold less frequently in women than in men, and the sex difference persists despite a rapid increase in female participation in sports. Establishing the reasons behind this difference could pinpoint targets for improved prevention of SrSCD. Therefore, this review summarizes existing knowledge on epidemiology, characteristics, and causes of SrSCD in females, and elaborates on proposed mechanisms behind the sex differences. Although literature concerning the aetiology of SrSCD in females is limited, proposed mechanisms include sex-specific variations in hormones, blood pressure, autonomic tone, and the presentation of acute coronary syndromes. Consequently, these biological differences impact the degree of cardiac hypertrophy, dilation, right ventricular remodelling, myocardial fibrosis, and coronary atherosclerosis, and thereby the occurrence of ventricular arrhythmias in male and female athletes associated with short- and long-term exercise. Finally, cardiac examinations such as electrocardiograms and echocardiography are useful tools allowing easy differentiation between physiological and pathological cardiac adaptations following exercise in women. However, as a significant proportion of SrSCD causes in women are non-structural or unexplained after autopsy, channelopathies may play an important role, encouraging attention to prodromal symptoms and family history. These findings will aid in the identification of females at high risk of SrSCD and development of targeted prevention for female sport participants.

2021 PACES Expert Consensus Statement on the Indications and Management of Cardiovascular Implantable Electronic Devices in Pediatric Patients: Developed in collaboration with and endorsed by the Heart Rhythm Society (HRS), the American College of Cardiology (ACC), the American Heart Association (AHA), and the Association for European Paediatric and Congenital Cardiology (AEPC) Endorsed by the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS)

In view of the increasing complexity of both cardiovascular implantable electronic devices (CIEDs) and patients in the current era, practice guidelines, by necessity, have become increasingly specific. This document is an expert consensus statement that has been developed to update and further delineate indications and management of CIEDs in pediatric patients, defined as ≤21 years of age, and is intended to focus primarily on the indications for CIEDs in the setting of specific disease categories. The document also highlights variations between previously published adult and pediatric CIED recommendations and provides rationale for underlying important differences. The document addresses some of the deterrents to CIED access in low- and middle-income countries and strategies to circumvent them. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by class of recommendation and level of evidence. Several questions addressed in this document either do not lend themselves to clinical trials or are rare disease entities, and in these instances recommendations are based on consensus expert opinion. Furthermore, specific recommendations, even when supported by substantial data, do not replace the need for clinical judgment and patient-specific decision-making. The recommendations were opened for public comment to Pediatric and Congenital Electrophysiology Society (PACES) members and underwent external review by the scientific and clinical document committee of the Heart Rhythm Society (HRS), the science advisory and coordinating committee of the American Heart Association (AHA), the American College of Cardiology (ACC), and the Association for European Paediatric and Congenital Cardiology (AEPC). The document received endorsement by all the collaborators and the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS). This document is expected to provide support for clinicians and patients to allow for appropriate CIED use, appropriate CIED management, and appropriate CIED follow-up in pediatric patients.

2021 PACES expert consensus statement on the indications and management of cardiovascular implantable electronic devices in pediatric patients

In view of the increasing complexity of both cardiovascular implantable electronic devices (CIEDs) and patients in the current era, practice guidelines, by necessity, have become increasingly specific. This document is an expert consensus statement that has been developed to update and further delineate indications and management of CIEDs in pediatric patients, defined as ≤21 years of age, and is intended to focus primarily on the indications for CIEDs in the setting of specific disease categories. The document also highlights variations between previously published adult and pediatric CIED recommendations and provides rationale for underlying important differences. The document addresses some of the deterrents to CIED access in low- and middle-income countries and strategies to circumvent them. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by class of recommendation and level of evidence. Several questions addressed in this document either do not lend themselves to clinical trials or are rare disease entities, and in these instances recommendations are based on consensus expert opinion. Furthermore, specific recommendations, even when supported by substantial data, do not replace the need for clinical judgment and patient-specific decision-making. The recommendations were opened for public comment to Pediatric and Congenital Electrophysiology Society (PACES) members and underwent external review by the scientific and clinical document committee of the Heart Rhythm Society (HRS), the science advisory and coordinating committee of the American Heart Association (AHA), the American College of Cardiology (ACC), and the Association for European Paediatric and Congenital Cardiology (AEPC). The document received endorsement by all the collaborators and the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS). This document is expected to provide support for clinicians and patients to allow for appropriate CIED use, appropriate CIED management, and appropriate CIED follow-up in pediatric patients.

Pregnancy in women with Brugada syndrome: Is there an increased arrhythmia risk? A case-series report

INTRODUCTION

In some rare arrhythmia syndromes, arrhythmia risk in female patients increases during pregnancy, necessitating extra controls. We wanted to evaluate if the increased risk for arrhythmia during pregnancy applies in women with Brugada syndrome and their potentially affected fetuses.

METHODS

A comprehensive literature search was performed on PubMed (MeSH search terms "Brugada syndrome," "pregnancy," "parturition," "labor," "delivery," "fetal death," and "stillbirth").

RESULTS

Overall, six case reports with a total of six patients were identified. Of these six patients (three carriers of an SCN5A variant, three not tested), two women (both with unknown SCN5A status), developed severe cardiac events during pregnancy. The first patient, with a previous history of aborted sudden cardiac arrest at the age of 12 years, developed ventricular fibrillation (VF), while the other was diagnosed with Brugada syndrome postpartum because of nocturnal agonal respiration during pregnancy.

CONCLUSION

These (limited, heterogenous) cases suggest that women with Brugada syndrome (and their possibly affected fetuses), might have an overall low tendency to develop arrhythmias during pregnancy, but important data on risk factors (SCN5A status) are lacking. Arrhythmia risk during pregnancy seems to increase in probands and those who have previously experienced cardiac events. We suggest the use of risk stratification in these women to improve patient care, lower the emotional stress and physical burden for the pregnant mother, and lower health costs. Furthermore, we plead for SCN5A analysis in all these women for use of risk stratification and to enable cascade screening especially for specialized care in children carrying an SCN5A mutation.

Early Experience with High-density Electroanatomical Mapping Using the Rhythmia™ Mapping System in Congenital and Pediatric Heart Disease

The Rhythmia™ system (Boston Scientific, Natick, MA, USA) facilitates the rapid acquisition of high-resolution electroanatomical and activation maps. However, there are limited data on its efficacy and safety in pediatric and adult congenital heart disease (CHD) patients. In a retrospective, observational cohort study, adult CHD and pediatric patients followed by pediatric cardiology underwent electrophysiologic study using the Rhythmia™ electroanatomic mapping system. Variables examined included the number of electroanatomical maps required, acquisition time, procedure time, fluoroscopy time, radiation dosage, and rate of recurrent arrhythmia. Twelve consecutive patients, including six male patients (50%), were included with an average age of 27.7 years (range: 11–64 years). Seven (58%) of these patients had a diagnosis of CHD [moderate complexity in two (17%) and great complexity in five patients (42%)] and 10 (83%) patients underwent ablation. A total of 37 high-density maps were created in 12 procedures, with a median of 8,140 mapping points, taking a median of 631 seconds. The median procedure time was 189.5 minutes. The median fluoroscopy time was 0.9 minutes, with eight (67%) patients receiving no fluoroscopy at all. Recurrence occurred in one patient (8%) over a median follow-up duration of 16 months (interquartile range: 12.8–17.3 months). No adverse periprocedural events were recorded. This study suggests the use of high-density electroanatomic mapping in adult CHD patients showed potential for rapid acquisition of highly detailed maps with minimal fluoroscopy time or risk of periprocedural events in the studied population.

High-risk features and predictors of unexplained syncope in the young SCD-SOS cohort

INTRODUCTION

The Sudden Cardiac Death-Screening of Risk FactOrS survey included a 12-lead electrocardiogram (ECG) plus a digital-based questionnaire and aimed to screen for warning signs of diseases that may course with sudden cardiac death in children and young adults. We aimed to estimate the prevalence of unexplained syncope (US) and characterize its high-risk features and predictors in this cohort.

METHODS AND RESULTS

We determined the most probable etiology of transient loss of consciousness (TLOC) episodes based on clinical criteria. US was an exclusion diagnosis and we analyzed its potential clinical and ECG predictors. Among 11 878 individuals, with a mean age of 21 ± 6 (range 6-40) years old, the cumulative incidence of TLOC was 26.5%, 76.2% corresponding to females. Reflex syncope was present in 66.4%, orthostatic hypotension in 8.2%, and 14.8% of the individuals had US. Unexplained syncope was independently associated with age < 18 years old (odds ratio [OR] 1.695; 95% confidence interval [CI] 1.26-2.29, p = .001), male gender (OR 1.642; 95% CI 1.22-2.22, p = .001), participation in competitive sports (OR 1.644; 95% CI 1.01-2.66, p = .043), syncope during exertion and/or palpitations preceding syncope (OR 2.556; 95% CI 1.92-3.40, p < .001), syncope after exertion (OR 2.662; 95% CI 1.73-4.10, p < .001), fever context (OR 9.606; 95% CI 4.13-22.34, p < .001), isolated previous syncopal episode (OR 2.780; 95% CI 0.2.06-3.75, p < .001), and history of palpitations requiring medical care (OR 1.945; 95% CI 1.14-3.31, p = .014). We found no ECG predictors of US in this population.

CONCLUSIONS

The cumulative incidence of TLOC in children and young adults is high and remains unexplained in an important proportion of individuals. We identified eight clinical characteristics that may be useful for the risk stratification of individuals evaluated in a nonacute setting.

2021 PACES Expert Consensus Statement on the Indications and Management of Cardiovascular Implantable Electronic Devices in Pediatric Patients

In view of the increasing complexity of both cardiovascular implantable electronic devices (CIEDs) and patients in the current era, practice guidelines, by necessity, have become increasingly specific. This document is an expert consensus statement that has been developed to update and further delineate indications and management of CIEDs in pediatric patients, defined as ≤21 years of age, and is intended to focus primarily on the indications for CIEDs in the setting of specific disease categories. The document also highlights variations between previously published adult and pediatric CIED recommendations and provides rationale for underlying important differences. The document addresses some of the deterrents to CIED access in low- and middle-income countries and strategies to circumvent them. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by class of recommendation and level of evidence. Several questions addressed in this document either do not lend themselves to clinical trials or are rare disease entities, and in these instances recommendations are based on consenus expert opinion. Furthermore, specific recommendations, even when supported by substantial data, do not replace the need for clinical judgment and patient-specific decision-making. The recommendations were opened for public comment to Pediatric and Congenital Electrophysiology Society (PACES) members and underwent external review by the scientific and clinical document committee of the Heart Rhythm Society (HRS), the science advisory and coordinating committee of the American Heart Association (AHA), the American College of Cardiology, (ACC) and the Association for European Paediatric and Congenital Cardiology (AEPC). The document received endorsement by all the collaborators and the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS). This document is expected to provide support for clinicians and patients to allow for appropriate CIED use, appropriate CIED management, and appropriate follow-up in pediatric patients.

2021 PACES Expert Consensus Statement on the Indications and Management of Cardiovascular Implantable Electronic Devices in Pediatric Patients

In view of the increasing complexity of both cardiovascular implantable electronic devices (CIEDs) and patients in the current era, practice guidelines, by necessity, have become increasingly specific. This document is an expert consensus statement that has been developed to update and further delineate indications and management of CIEDs in pediatric patients, defined as ≤21 years of age, and is intended to focus primarily on the indications for CIEDs in the setting of specific disease categories. The document also highlights variations between previously published adult and pediatric CIED recommendations and provides rationale for underlying important differences. The document addresses some of the deterrents to CIED access in low- and middle-income countries and strategies to circumvent them. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by class of recommendation and level of evidence. Several questions addressed in this document either do not lend themselves to clinical trials or are rare disease entities, and in these instances recommendations are based on consensus expert opinion. Furthermore, specific recommendations, even when supported by substantial data, do not replace the need for clinical judgment and patient-specific decision-making. The recommendations were opened for public comment to Pediatric and Congenital Electrophysiology Society (PACES) members and underwent external review by the scientific and clinical document committee of the Heart Rhythm Society (HRS), the science advisory and coordinating committee of the American Heart Association (AHA), the American College of Cardiology (ACC), and the Association for European Paediatric and Congenital Cardiology (AEPC). The document received endorsement by all the collaborators and the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS). This document is expected to provide support for clinicians and patients to allow for appropriate CIED use, appropriate CIED management, and appropriate CIED follow-up in pediatric patients.

2021 PACES Expert Consensus Statement on the Indications and Management of Cardiovascular Implantable Electronic Devices in Pediatric Patients: Executive Summary

Guidelines for the implantation of cardiac implantable electronic devices (CIEDs) have evolved since publication of the initial ACC/AHA pacemaker guidelines in 1984 [1]. CIEDs have evolved to include novel forms of cardiac pacing, the development of implantable cardioverter defibrillators (ICDs) and the introduction of devices for long term monitoring of heart rhythm and other physiologic parameters. In view of the increasing complexity of both devices and patients, practice guidelines, by necessity, have become increasingly specific. In 2018, the ACC/AHA/HRS published Guidelines on the Evaluation and Management of Patients with Bradycardia and Cardiac Conduction Delay [2], which were specific recommendations for patients >18 years of age. This age-specific threshold was established in view of the differing indications for CIEDs in young patients as well as size-specific technology factors. Therefore, the following document was developed to update and further delineate indications for the use and management of CIEDs in pediatric patients, defined as ≤21 years of age, with recognition that there is often overlap in the care of patents between 18 and 21 years of age.

This document is an abbreviated expert consensus statement (ECS) intended to focus primarily on the indications for CIEDs in the setting of specific disease/diagnostic categories. This document will also provide guidance regarding the management of lead systems and follow-up evaluation for pediatric patients with CIEDs. The recommendations are presented in an abbreviated modular format, with each section including the complete table of recommendations along with a brief synopsis of supportive text and select references to provide some context for the recommendations. This document is not intended to provide an exhaustive discussion of the basis for each of the recommendations, which are further addressed in the comprehensive PACES-CIED document [3], with further data easily accessible in electronic searches or textbooks.

Brugada syndrome associated with out-of-hospital cardiac arrest: A case report

BACKGROUND

Brugada syndrome (BrS) is an inherited disease characterized by an electrocardiogram (ECG) with a coved-type ST-segment elevation in the right precordial leads (V1-V3), which predisposes to sudden cardiac death (SCD) due to polymorphic ventricular tachycardia or ventricular fibrillation in the absence of structural heart disease. We report the case of a 29-year-old man with out-of-hospital cardiac arrest. BrS is associated with a high incidence of SCD in adults, and increasing the awareness of BrS and prompt recognition of the Brugada ECG pattern can be lifesaving.

CASE SUMMARY

A 29-year-old man suffered from out-of-hospital cardiac arrest, and after defibrillation, his ECG demonstrated a coved-type elevated ST segment in V1 and V2. These findings were compatible with type 1 Brugada pattern, and ECG of his brother showed a type 2 Brugada pattern. The diagnosis was BrS, NYHF IV, multiple organ dysfunction syndrome, sepsis, and hypoxic ischemic encephalopathy. The patient had no arrhythmia episodes after discharge throughout a follow-up period of 36 mo.

CONCLUSION

Increasing awareness of BrS and prompt recognition of the Brugada ECG pattern can be lifesaving.

Clinical characteristics and risk of arrhythmic events in patients younger than 12 years diagnosed with Brugada syndrome

BACKGROUND

Brugada syndrome (BrS) is an inheritable disease with an increased risk of sudden cardiac death. Although several score systems have been proposed, the management of children with BrS has been inconsistently described.

OBJECTIVE

The purpose of this study was to identify the characteristics, outcome, and risk factors associated with cardiovascular and arrhythmic events (AEs) in children younger than 12 years with BrS.

METHODS

In this single-center case series, all children with spontaneous or drug/fever-induced type 1 Brugada electrocardiographic (ECG) pattern and younger than 12 years at the time of diagnosis were enrolled.

RESULTS

Forty-three patients younger than 12 years at the time of diagnosis were included. The median follow-up was 3.97 years (interquartile range 2-12 years). In terms of first-degree atrioventricular block, premature beats, nonmalignant AEs, malignant AEs, and episodes of syncope, no significant differences were observed either between patients with spontaneous and drug/fever-induced type 1 Brugada ECG pattern or between female and male patients (except a significant difference between female and male patients for first-degree atrioventricular block). A higher incidence of malignant AEs was observed in patients with syncope (3 of 8 [37.5%] vs 0 of 35 [0%]; P = .005) than in patients without syncope. SCN5A mutations were associated with a higher occurrence of malignant AEs (3 of 14 [21.4%] vs 0 of 25 [0%]; P = .04) compared with no SCN5A mutations.

CONCLUSION

A spontaneous type 1 Brugada ECG pattern is not associated with a higher incidence of syncope, first-degree atrioventricular block, premature beats, nonmalignant AEs, and malignant AEs than the drug/fever-induced type 1 Brugada ECG pattern. Syncope events are correlated with an increased incidence of malignant AEs. Moreover, SCN5A mutations are associated with a higher occurrence of malignant AEs.

Ventricular Tachyarrhythmia Risk in Paediatric/Young vs. Adult Brugada Syndrome Patients: A Territory-Wide Study

Introduction: Brugada syndrome (BrS) is a cardiac ion channelopathy with a higher prevalence in Asia compared to the Western populations. The present study compared the differences in clinical and electrocardiographic (ECG) presentation between paediatric/young (≤25 years old) and adult (>25 years) BrS patients.

Method: This was a territory-wide retrospective cohort study of consecutive BrS patients presenting to public hospitals in Hong Kong. The primary outcome was spontaneous ventricular tachycardia/ventricular fibrillation (VT/VF).

Results: The cohort consists of 550 consecutive patients (median age of initial presentation = 51 ± 23 years; female = 7.3%; follow-up period = 83 ± 80 months), divided into adult (n = 505, mean age of initial presentation = 52 ± 19 years; female = 6.7%; mean follow-up period = 83 ± 80 months) and paediatric/young subgroups (n = 45, mean age of initial presentation = 21 ± 5 years, female = 13.3%, mean follow-up period = 73 ± 83 months). The mean annual VT/VF incidence rate were 17 and 25 cases per 1,000 patient-year, respectively. Multivariate analysis showed that initial presentation of type 1 pattern (HR = 1.80, 95% CI = [1.02, 3.15], p = 0.041), initial asymptomatic presentation (HR = 0.26, 95% CI = [0.07, 0.94], p = 0.040) and increased P-wave axis (HR = 0.98, 95% CI = [0.96, 1.00], p = 0.036) were significant predictors of VT/VF for the adult subgroup. Only initial presentation of VT/VF was predictive (HR = 29.30, 95% CI = [1.75, 492.00], p = 0.019) in the paediatric/young subgroup.

Conclusion: Clinical and ECG presentation of BrS vary between the paediatric/young and adult population in BrS. Risk stratification and management strategies for younger patients should take into consideration and adopt an individualised approach.

Standard ECG in Brugada Syndrome as a Marker of Prognosis: From Risk Stratification to Pathophysiological Insights

Background

The 12‐lead ECG plays a key role in the diagnosis of Brugada syndrome (BrS). Since the spontaneous type 1 ECG pattern was first described, several other ECG signs have been linked to arrhythmic risk, but results are conflicting.

Methods and Results

We performed a systematic review to clarify the associations of these specific ECG signs with the risk of syncope, sudden death, or equivalents in patients with BrS. The literature search identified 29 eligible articles comprising overall 5731 patients. The ECG findings associated with an incremental risk of syncope, sudden death, or equivalents (hazard ratio ranging from 1.1–39) were the following: localization of type 1 Brugada pattern (in V2 and peripheral leads), first‐degree atrioventricular block, atrial fibrillation, fragmented QRS, QRS duration >120 ms, R wave in lead aVR, S wave in L1 (≥40 ms, amplitude ≥0.1 mV, area ≥1 mm²), early repolarization pattern in inferolateral leads, ST‐segment depression, T‐wave alternans, dispersion of repolarization, and Tzou criteria.

Conclusions

At least 12 features of standard ECG are associated with a higher risk of sudden death in BrS. A multiparametric risk assessment approach based on ECG parameters associated with clinical and genetic findings could help improve current risk stratification scores of patients with BrS and warrants further investigation.

Registration

URL: https://www.crd.york.ac.uk/prospero/. Unique identifier: CRD42019123794.

Clinical significance of inferolateral early repolarisation and late potentials in children with Brugada Syndrome

INTRODUCTION

The clinical utility of inferolateral early repolarisation (ER) and late potentials (LP) in children with Brugada Syndrome (BrS) has not been previously evaluated. The aim of this study was to determine the prevalence of electrocardiographic (ECG) abnormalities in children with BrS, and to investigate their relationship with clinical outcomes.

METHODS

43 patients with BrS and 47 controls aged ≤18 undergoing systematic clinical and ECG evaluation, including signal-averaged ECG (SAECG) and pharmacological provocation testing, between 2003 and 2019 were included.

RESULTS

Four patients with BrS (9%) presented with a spontaneous type 1 Brugada pattern; the remaining 39 (91%) were diagnosed following ajmaline provocation testing. Twelve BrS patients (28%) had late potentials (LP) on SAECG compared to 1 (2%) in controls (p = 0.001). LP were more common in 5 patients with a high-risk phenotype (60% vs 24%) but this was not statistically significant. Twelve patients with BrS (28%) had inferolateral early repolarisation (ER) and 2 (5%) had fractionated QRS (f-QRS), but there were no statistically-significant differences with controls in these parameters. A significant arrhythmia (non-sustained ventricular tachycardia or atrial fibrillation) was seen in 4 patients (9%).

CONCLUSIONS

This study shows a high prevalence of SAECG abnormalities in children with BrS compared with controls, but this was not significantly associated with a high-risk phenotype.

Editor-in-Chief's Top Picks From 2019

Each week, I record audio summaries for every paper in JACC, as well as an issue summary. Although this process is quite time-consuming, I have become familiar with every paper that we publish. Thus, I have personally selected the top 100 papers (both Original Investigations and Review Articles, and an occasional Editorial Comment) from the distinct specialties each year. In addition to my personal choices, I have included papers that have been the most accessed or downloaded on our websites, as well as those selected by the JACC Editorial Board members. In order to present the full breadth of this important research in a consumable fashion, we will present these abstracts in this issue of JACC, as well as most of the central illustrations, with the realization that a magnifying glass will be be needed for appropriate visualization. The highlights comprise the following sections: Basic & Translational Research, Cardiac Failure & Myocarditis, Cardiomyopathies/Congenital & Genetics, Cardio-Oncology, Coronary Disease & Interventions, Hypertension, Imaging, Metabolic & Lipid Disorders, Neurovascular Disease & Dementia, Promoting Health & Prevention, Rhythm Disorders & Thromboembolism, Valvular Heart Disease, and Vascular Medicine (1-100).

ArrhythmoGenoPharmacoTherapy

This review is focusing on the understanding of various factors and components governing and controlling the occurrence of ventricular arrhythmias including (i) the role of various ion channel-related changes in the action potential (AP), (ii) electrocardiograms (ECGs), (iii) some important arrhythmogenic mediators of reperfusion, and pharmacological approaches to their attenuation. The transmembrane potential in myocardial cells is depending on the cellular concentrations of several ions including sodium, calcium, and potassium on both sides of the cell membrane and active or inactive stages of ion channels. The movements of Na+, K+, and Ca2+ via cell membranes produce various currents that provoke AP, determining the cardiac cycle and heart function. A specific channel has its own type of gate, and it is opening and closing under specific transmembrane voltage, ionic, or metabolic conditions. APs of sinoatrial (SA) node, atrioventricular (AV) node, and Purkinje cells determine the pacemaker activity (depolarization phase 4) of the heart, leading to the surface manifestation, registration, and evaluation of ECG waves in both animal models and humans. AP and ECG changes are key factors in arrhythmogenesis, and the analysis of these changes serve for the clarification of the mechanisms of antiarrhythmic drugs. The classification of antiarrhythmic drugs may be based on their electrophysiological properties emphasizing the connection between basic electrophysiological activities and antiarrhythmic properties. The review also summarizes some important mechanisms of ventricular arrhythmias in the ischemic/reperfused myocardium and permits an assessment of antiarrhythmic potential of drugs used for pharmacotherapy under experimental and clinical conditions.

Diagnostic challenges of Brugada Syndrome in pediatric patients

Although most cases of Brugada syndrome have been described in adults, pediatric patients with the disease have been reported since the original article from Josep and Pedro Brugada. Herein is presented the case series of Brugada syndrome in pediatric population of the National Institute of Cardiology Ignacio Chavez. One boy and two adolescent males had palpitations as clinical presentation of the disease. Atrial arrhythmias were documented in two, in the third case there was a high clinical suspicion and quinidine abolished symptoms. The aim of this report is to highlight the importance of performing a detailed clinical history as well as the usefulness of high precordial leads for the diagnosis of this entity.

Current Controversies and Challenges in Brugada Syndrome

More than three decades since its initial description in 1993, Brugada syndrome remains engulfed in controversy. This review aims to shed light on the main challenges surrounding the diagnostic pathway and criteria, risk stratification of asymptomatic patients, pharmacological and interventional risk modification strategies as well as our current pathophysiological understanding of the disease.

Editorial commentary: When should the patient with an inherited cardiac disease have an ICD?

The implantable cardioverter defibrillator (ICD) is often considered a routine intervention for an inherited heart rhythm disorder (IHRD) despite there being little to no randomized data for non-ischemic indications. Furthermore, existing IHRD studies often do not report adverse ICD outcomes, and observational data increasingly show that complications are under-recognized. Only recently have tools emerged to address the rational use of ICDs for specific forms of IHRD, although the acceptable risk of device complications remains unestablished. Here, we summarize the evidence of ICD benefit and harm in IHRD, highlight current knowledge gaps, and propose alternative and adjunctive options to the transvenous ICD.

Evaluation After Sudden Death in the Young

Sudden cardiac death is defined as a death occurring usually within an hour of onset of symptoms, arising from an underlying cardiac disease. Sudden cardiac death is a complication of a number of cardiovascular diseases and is often unexpected. In individuals aged <35 years, unexplained sudden cardiac death is the most common presentation. A significant proportion of sudden cardiac death in the young (≤35 years) events may be precipitated by underlying inherited cardiac conditions, including both heritable cardiomyopathies and inherited arrhythmia syndromes (also known as cardiac channelopathies). Tragically, sudden death may be the first manifestation of the disease in a family and, therefore, clinical and genetic evaluation of surviving family members forms a key role in diagnosing the underlying inherited cardiac condition in the family. This is particularly relevant when considering that most inherited cardiac conditions are inherited in an autosomal dominant manner meaning that surviving family members have a 50% chance of inheriting the same disease substrate. This review will outline the underlying causes of sudden cardiac death in the young and outline our universal approach to familial evaluation following a young person’s sudden death.