Vigorous Exercise in Patients With Congenital Long QT Syndrome: Results of the Prospective, Observational, Multinational LIVE-LQTS Study.

BACKGROUND: Whether vigorous exercise increases risk of ventricular arrhythmias for individuals diagnosed and treated for congenital long QT syndrome (LQTS) remains unknown. METHODS: The National Institutes of Health-funded LIVE-LQTS study (Lifestyle and Exercise in the Long QT Syndrome) prospectively enrolled individuals 8 to 60 years of age with phenotypic and/or genotypic LQTS from 37 sites in 5 countries from May 2015 to February 2019. Participants (or parents) answered physical activity and clinical events surveys every 6 months for 3 years with follow-up completed in February 2022. Vigorous exercise was defined as ≥6 metabolic equivalents for >60 hours per year. A blinded Clinical Events Committee adjudicated the composite end point of sudden death, sudden cardiac arrest, ventricular arrhythmia treated by an implantable cardioverter defibrillator, and likely arrhythmic syncope. A National Death Index search ascertained vital status for those with incomplete follow-up. A noninferiority hypothesis (boundary of 1.5) between vigorous exercisers and others was tested with multivariable Cox regression analysis. RESULTS: Among the 1413 participants (13% <18 years of age, 35% 18-25 years of age, 67% female, 25% with implantable cardioverter defibrillators, 90% genotype positive, 49% with LQT1, 91% were treated with beta-blockers, left cardiac sympathetic denervation, and/or implantable cardioverter defibrillator), 52% participated in vigorous exercise (55% of these competitively). Thirty-seven individuals experienced the composite end point (including one sudden cardiac arrest and one sudden death in the nonvigorous group, one sudden cardiac arrest in the vigorous group) with overall event rates at 3 years of 2.6% in the vigorous and 2.7% in the nonvigorous exercise groups. The unadjusted hazard ratio for experience of events for the vigorous group compared with the nonvigorous group was 0.97 (90% CI, 0.57-1.67), with an adjusted hazard ratio of 1.17 (90% CI, 0.67-2.04). The upper 95% one-sided confidence level extended beyond the 1.5 boundary. Neither vigorous or nonvigorous exercise was found to be superior in any group or subgroup. CONCLUSIONS: Among individuals diagnosed with phenotypic and/or genotypic LQTS who were risk assessed and treated in experienced centers, LQTS-associated cardiac event rates were low and similar between those exercising vigorously and those not exercising vigorously. Consistent with the low event rate, CIs are wide, and noninferiority was not demonstrated. These data further inform shared decision-making discussions between patient and physician about exercise and competitive sports participation. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02549664.

Utilizing median and maximum QTc values improves prediction of breakthrough cardiac events in pediatric long QT syndrome.

INTRODUCTION: Although prior studies indicate that a QTc > 500 ms on a single baseline 12-lead electrocardiogram (ECG) is associated with significantly increased risk of arrhythmic events in long QT syndrome (LQTS), less is known about the risk of persistent QT prolongation. We sought to determine QTc persistence and its prognostic effect on breakthrough cardiac events (BCEs) among pediatric patients treated for LQTS. METHODS: We performed a retrospective analysis of 433 patients with LQTS evaluated, risk-stratified, and undergoing active guideline-based LQTS treatment between 1999 and 2019. BCEs were defined as arrhythmogenic syncope/seizure, sudden cardiac arrest (SCA), appropriate VF-terminating ICD shock, and sudden cardiac death (SCD). RESULTS: During the median follow-up of 5.5 years (interquartile range [IQR] = 3-9), 32 (7%) patients experienced a total of 129 BCEs. A maximum QTc threshold of 520 ms and median QTc threshold of 490 ms were determined to be strong predictors for BCEs. A landmark analysis controlling for age, sex, genotype, and symptomatic status demonstrated models utilizing both the median QTc and maximum QTc demonstrated the highest discriminatory value (c-statistic = 0.93-0.95). Patients in the high-risk group (median QTc > 490 ms and maximum QTc > 520 ms) had a significantly lower BCE free survival (70%-81%) when compared to patients in both medium-risk (93%-97%) and low-risk (98%-99%) groups. CONCLUSIONS: The risk of BCE among patients treated for LQTS increases not only based upon their maximum QTc, but also their median QTc (persistence of QTc prolongation). Patients with a maximum QTc > 520 ms and median QTc > 490 ms over serial 12-lead ECGs are at the highest risk of BCE while on guideline-directed medical therapy.

Hypertrophic cardiomyopathy and competitive sports: let 'em play?

PURPOSE OF REVIEW: Hypertrophic cardiomyopathy (HCM) is one of the most common cardiovascular genetic conditions. Although most patients with HCM typically do well clinically, there is a small but real incidence of sudden cardiac death. A diagnosis of HCM was previously a reason for complete exclusion in sports, particularly competitive sports.However, many of these recommendations are based on expert consensus, and much data has been published in the last decade furthering the scientific knowledge in this area, and allowing athletes who may have been previously excluded the potential to participate in strenuous activities and competitive sports. RECENT FINDINGS: With recent publications on participation in sports with HCM, as well as an emphasis on shared decision-making, more athletes with HCM are participating in competitive sports, even at a professional level. Even contact sports in the presence of an implantable cardioverter-defibrillator are no longer mutually exclusive in the current era. SUMMARY: Previous guidelines were likely overly restrictive for patients with HCM. Although there is a risk of sudden death that cannot be ignored, the potential for shared decision making as well as medical guidance are entering a new era in all aspects of medicine, particularly in sports participation.

Utility of routine follow-up defibrillation safety margin testing in young patients with epicardial implantable cardioverter-defibrillators.

BACKGROUND: Routine defibrillation threshold testing (DFT) of transvenous implantable defibrillators (ICDs) has largely been in decline. In patients with non-transvenous ICDs that utilize subcutaneous and pleural ICD leads, serial DFT testing can detect a significant number of failures. Data about the utility of follow-up defibrillation safety margin testing (DSM) testing in pediatric patients and young adults with an epicardial ICD are lacking. METHODS: Patients aged < 25 years old who underwent epicardial ICD placement at Mayo Clinic from 2014 to 2023 with at least one follow-up DSM test were included. The patients were divided into a "routine" (R) and "clinically indicated" (CI) group based on the index of clinical concern. Inadequate DSM was defined as unsuccessful defibrillation at an output of less than 10 J below the maximum output of the device. The purpose of this study was to assess the utility of follow-up DSM testing. RESULTS: An epicardial ICD system was placed in 122 patients. A total of 26 patients met inclusion criteria and underwent a total of 47 DSM follow up tests. Inadequate DSM occurred in 1/33 (3%) in the R group and 2/14 (14%) DSM tests in the CI group. The median follow-up period was 54 and 36 months for the R and CI group, respectively. CONCLUSIONS: Our data suggest that epicardial ICDs are reliable and routine follow-up DSM testing may not be necessary for all patients. DSM testing should be performed in individuals with epicardial ICD systems when there is clinical concern about lead or coil performance.

Empiric Slow Pathway Cryoablation in Symptomatic Children Without Documented Supraventricular Tachycardia.

In symptomatic children without documented supraventricular tachycardia (SVT) and non-inducible atrioventricular nodal reentry tachycardia (AVNRT) the benefit of empiric slow pathway (SP) ablation is unknown. We evaluated 62 symptomatic patients without documented SVT that underwent electrophysiology study (EPS). The purpose of this study was to determine if symptoms improved after empiric SP ablation in children without documented SVT and without inducible AVNRT. Sixty-two symptomatic patients without previously documented SVT underwent EPS; 31 (50%) had inducible AVNRT and underwent SP ablation, 20 (32%) were non-inducible and underwent empiric SP ablation, 11 (18%) were non-inducible and had no ablation. After a mean follow-up of 23 ± 18 months there was no significant difference in freedom from symptoms within the non-inducible cohort regardless of whether empiric SP ablation was performed (p = 0.135). There was a significant improvement in symptoms at follow-up after SP ablation when comparing inducible and non-inducible patients (p = 0.020). During follow-up no patients had documented SVT. Symptomatic children without documented SVT do not benefit from empiric SP ablation when AVNRT cannot be induced.

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.

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.

B cells in rheumatoid arthritis synovial tissues encode focused antibody repertoires that include antibodies that stimulate macrophage TNF-α production.

Rheumatoid arthritis (RA) is characterized by the production of anti-citrullinated protein antibodies (ACPAs). To gain insights into the relationship between ACPA-expressing B cells in peripheral blood (PB) and synovial tissue (ST), we sequenced the B cell repertoire in paired PB and ST samples from five individuals with established, ACPA+ RA. Bioinformatics analysis of paired heavy- and light-chain sequences revealed clonally-related family members shared between PB and ST. ST-derived antibody repertoires exhibited reduced diversity and increased normalized clonal family size compared to PB-derived repertoires. Functional characterization showed that seven recombinant antibodies (rAbs) expressed from subject-derived sequences from both compartments bound citrullinated antigens and immune complexes (ICs) formed using one ST-derived rAb stimulated macrophage TNF-α production. Our findings demonstrate B cell trafficking between PB and ST in subjects with RA and ST repertoires include B cells that encode ACPA capable of forming ICs that stimulate cellular responses implicated in RA pathogenesis.

Wolff-Parkinson-White syndrome: De novo variants and evidence for mutational burden in genes associated with atrial fibrillation.

BACKGROUND: Wolff-Parkinson-White (WPW) syndrome is a relatively common arrhythmia affecting ~1-3/1,000 individuals. Mutations in PRKAG2 have been described in rare patients in association with cardiomyopathy. However, the genetic basis of WPW in individuals with a structurally normal heart remains poorly understood. Sudden death due to atrial fibrillation (AF) can also occur in these individuals. Several studies have indicated that despite ablation of an accessory pathway, the risk of AF remains high in patients compared to general population. METHODS: We applied exome sequencing in 305 subjects, including 65 trios, 80 singletons, and 6 multiple affected families. We used de novo analysis, candidate gene approach, and burden testing to explore the genetic contributions to WPW. RESULTS: A heterozygous deleterious variant in PRKAG2 was identified in one subject, accounting for 0.6% (1/151) of the genetic basis of WPW in this study. Another individual with WPW and left ventricular hypertrophy carried a known pathogenic variant in MYH7. We found rare de novo variants in genes associated with arrhythmia and cardiomyopathy (ANK2, NEBL, PITX2, and PRDM16) in this cohort. There was an increased burden of rare deleterious variants (MAF ≤ 0.005) with CADD score ≥ 25 in genes linked to AF in cases compared to controls (P = .0023). CONCLUSIONS: Our findings show an increased burden of rare deleterious variants in genes linked to AF in WPW syndrome, suggesting that genetic factors that determine the development of accessory pathways may be linked to an increased susceptibility of atrial muscle to AF in a subset of patients.

Placement of Reveal LINQ Device in the Left Anterior Axillary Position.

Implantable loop recorders (ILR) are utilized for long-term rhythm monitoring. Typical placement of the Medtronic Reveal LINQ along the left parasternal border may compromise the quality and/or feasibility of future imaging studies. We sought to evaluate the utility of placing an ILR in the left anterior axillary position and the impact on the quality of cardiac imaging. We reviewed patients from May 2017 to June 2018 who had placement of a Reveal LINQ device in the left anterior axillary position. Demographic, procedural, and clinical data were collected via retrospective review. Cardiac magnetic resonance imaging (MRI) studies were reviewed for image quality after ILR placement. Eight patients met inclusion criteria for this study (median age 6 years, 50% female). Six patients (75%) had an ILR placed in the operating room, while all others were placed in the electrophysiology lab. All patients demonstrated acceptable R waves for diagnostic evaluation (median = 0.85 mV, range 0.24-1.7 mV). Cardiac MRI was obtained in 7 patients following ILR placement with diagnostic image quality and no adverse events. One device was explanted 28 days after placement due to concern for possible infection. No other devices required removal or revision (median follow up duration 11 months, IQR 8-13.5). ILR placement in the left anterior axillary position can record adequate signals in pediatric patients. In addition, axillary ILR device position may allow for completion of cardiac imaging, particularly cardiac MRI, without significant artifacts which is critical for patients with congenital heart disease.

Current Interventional and Surgical Management of Congenital Heart Disease: Specific Focus on Valvular Disease and Cardiac Arrhythmias.

Successful outcome in the care of patients with congenital heart disease depends on a comprehensive multidisciplinary team. Surgery is offered for almost every heart defect, despite complexity. Early mortality for cardiac surgery in the neonatal period is ≈10% and beyond infancy is <5%, with 90% to 95% of patients surviving with a good quality of life into the adult years. Advances in imaging have facilitated accurate diagnosis and planning of interventions and surgical procedures. Similarly, advances in the perioperative medical management of patients, particularly with intensive care, has also contributed to improving outcomes. Arrhythmias and heart failure are the most common late complications for the majority of defects, and reoperation for valvar problems is common. Lifelong surveillance for monitoring of recurrent or residual structural heart defects, as well as periodic assessment of cardiac function and arrhythmia monitoring, is essential for all patients. The field of congenital heart surgery is poised to incorporate new innovations such as bioengineered cells and scaffolds that will iteratively move toward bioengineered patches, conduits, valves, and even whole organs.

Cosmetic outcomes and quality of life in children with cardiac implantable electronic devices.

BACKGROUND: Axillary implant location is an alternative implant location in patients for cardiac implantable electronic devices (CIEDs) for the purposes of improved cosmetic outcome. The impact from the patient's perspective is unknown. The purpose of this study was to compare scar perception scores and quality of life (QOL) in pediatric patients with axillary CIED implant location versus the standard infraclavicular approach. METHODS: This is a multicenter prospective study conducted at eight pediatric centers and it includes patients aged from 8 to 18 years with a CIED. Patients with prior sternotomy were excluded. Scar perception and QOL outcomes were compared between the infraclavicular and axillary implant locations. RESULTS: A total of 141 patients (83 implantable cardioverter defibrillator [ICD]/58 pacemakers) were included, 55 with an axillary device and 86 with an infraclavicular device. Patients with an ICD in the axillary position had better perception of scar appearance and consciousness. Patients in the axillary group reported, on average, a total Pediatric QOL Inventory score that was 6 (1, 11) units higher than the infraclavicular group, after adjusting for sex and race (P = 0.02). CONCLUSIONS: QOL is significantly improved in axillary in comparison to the infraclavicular CIED position, regardless of device type. Scar perception is improved in patients with ICD in the axillary position.

Outcomes of atrial arrhythmia radiofrequency catheter ablation in patients with Ebstein's anomaly.

Aims: Atrial arrhythmias are common in patients with Ebstein's anomaly (EA) despite cardiac surgical repair and concomitant Maze procedures. We aimed to evaluate the outcome of radiofrequency catheter ablation in this group of patients. Methods and results: All patients with EA and atrial arrhythmias who underwent catheter ablation for atrial arrhythmias between 1/1999 and 1/2016 were included. Atrial arrhythmia recurrence was identified as the primary outcome; secondary outcomes included repeat ablation, need for antiarrhythmic medications after ablation, and death. Predictors of recurrence were sought using univariate analysis. 22 patients (median age 42 years, 54.5% male) were included. Atrial flutter was the most common presenting arrhythmia (n = 14 patients, 63.5%), whereas focal atrial tachycardia (FAT) and atrial fibrillation were identified in 5 (22.7%) and 2 patients (9.1%), respectively, with both atrial flutter/fibrillation evident in a single patient 1 (4.5%). 8 patients (36.4%) had a history of right-sided maze procedures. Cavotricuspid isthmus atrial flutter (CTI-AFl) was the most commonly induced arrhythmia (n = 13, 59.1%), followed by incisional intra-atrial re-entrant tachycardia (IART; n = 4, 18.2%), and FAT (n = 4, 18.2%); 3 patients also underwent left-side ablation with concomitant pulmonary vein isolation (13.6%). 1-year and 5-year atrial arrhythmia recurrence rates were 10.0% and 41.2%, respectively. 7 patients (31.8%) underwent redo ablations, and anti-arrhythmic medication was utilized in 8 patients (36.4%) post-ablation. Neither ablation location nor echocardiographic parameters were found to be predictors of arrhythmia recurrence. Conclusion: Catheter ablation of atrial arrhythmias in patients with EA has a favorable outcome overall with an acceptable recurrence and safety profile; left-sided ablations are rarely necessary. Despite prior Maze and catheter ablation procedures, CTI-AFl and IART recurrences predominate.

Intravascular and hybrid intraoperative stent placement for baffle obstruction in transposition of the great arteries after atrial switch.

OBJECTIVES: To report our experience with intravascular and hybrid intra-operative stent placement for baffle obstruction in patients with complete transposition of the great arteries (TGA) after the atrial switch (Mustard/Senning) operation. BACKGROUND: Venous baffle obstruction is a challenging complication after atrial switch operation in patients with TGA. Traditional treatment options include intravascular stenting or surgery. METHODS: A retrospective analysis of Mayo Clinic's electronic medical record was completed to identify consecutive pediatric and adult patients with TGA after atrial switch who underwent baffle stent implantation from 1994 to 2015. RESULTS: Overall, 64 patients were referred for cardiac catheterization, in whom 47 (73%) were noted to have hemodynamic and angiographic evidence of baffle obstruction. A total of 20 patients mean age 33 (range: 8-46) years old underwent stent implantation of baffle stenosis at a mean of 33 (range: 7.5-45) years after initial atrial switch operation (Mustard, n = 19; Senning, n = 1). Overall, 27 baffles were stented in 20 patients via the following approaches: intravascular (17); hybrid surgical (3); staged intravascular & hybrid (2). Sites of stent placement were: superior vena cava (SVC) (13); inferior vena cava (IVC) (9); pulmonary venous baffle (5). Three patients had stent placement in the SVC and IVC baffles during the same procedure. Procedural adverse events occurred in 2/22 cases (9%) including creation of unintentional baffle leak (n = 1) and stent migration (n = 1). There was no procedure-related mortality. At follow-up (median 2, range 0.02-10 years), significantly improved NYHA class and mean Doppler baffle gradient were demonstrated (P < 0.05). Mild baffle re-stenosis (mean Doppler gradient; 2-3 mmHg) occurred in two patients who have not required re-intervention. Trivial baffle leak was noted in four patients. Baffle re-intervention was only occurred in one patient. One patient with pre-procedural Class IV symptoms died 3.5 months after stent implantation. CONCLUSIONS: This study is the largest reported experience of intravascular and intra-operative hybrid stent placement for patients with TGA after atrial switch. Transcatheter and minimally invasive hybrid intraoperative surgical stent placement are an effective strategy for relief of systemic and pulmonary venous baffle obstruction. © 2016 Wiley Periodicals, Inc.

Lead extraction outcomes in patients with congenital heart disease.

AIMS: Patients with congenital heart disease (CHD) are at increased risk for intracardiac device malfunction and infection that may necessitate extraction; however, the risk of extraction is poorly understood. This study addresses the safety of extraction in patients with structural heart disease and previous cardiac surgery. METHODS AND RESULTS: This retrospective study included 40 CHD and 80 matched control patients, who underwent transvenous lead extractions between 2001 and 2014. Only leads >12 months were included. There were 77 leads in CHD patients and 146 in controls. The mean age was 38 ± 16 years in CHD patients. Ninety per cent of CHD patients had ≥1 cardiac surgeries when compared with 21% of controls (P < 0.001). The number of abandoned leads was significantly different (17 vs. 3, P < 0.001). Lead age was similar with an average duration of 83 ± 87 months in CHD patients and 62 ± 65 months in controls (P = 0.24). There was no significant difference in extraction techniques. Manual traction was successful in 40% of CHD patients and 47% of controls, and advanced techniques were used in 60 and 53% of CHD patients and controls, respectively. Complete extraction was achieved in 94% of the patients in both groups. There was no significant difference in complications. CONCLUSION: Lead extraction can be safely performed in patients with CHD. Despite anatomic abnormalities and longer implantation times, the difficulty of lead extraction in patients with CHD is comparable with controls.

Electrocardiographic abnormalities in elite high school athletes: comparison to adolescent hypertrophic cardiomyopathy.

BACKGROUND: In athletes, ECG changes from physiological cardiac remodelling are common but can overlap with findings from a pathological disorder. We compared ECG findings in a group of elite high school athletes to a cohort of adolescents with hypertrophic cardiomyopathy (HCM). METHODS/RESULTS: We prospectively performed 15-lead ECGs and echocardiograms in 147 elite high school athletes. Student-athlete ECGs were compared in blinded fashion to ECGs of 148 adolescents with HCM of similar age and ethnicity. Standard ECG hypertrophy criteria and established expert opinion guidelines (European Society of Cardiology, ESC and Seattle criteria) were analysed. All student-athletes had normal echocardiograms. Overall, 77/147 (52%) of student-athletes met standard ECG criteria for ventricular hypertrophy compared to 126/148 (85%) adolescents with HCM (p<0.0001). There were 112/148 (76%) adolescents with HCM who had pathological Q-waves, T-wave inversion and/or ST-segment depression compared to 1/147 (1%) athletes (p<0.0001). Most patients with HCM (84%, 124/148) had ≥1 abnormal ECG finding(s) according to Seattle criteria, compared to 1% of student-athletes (2/147). Similarly, 130/148 (88%) patients with HCM met group-2 ESC criteria (abnormal), compared to 36/147 (24%) student-athletes (p<0.0001). CONCLUSIONS: Over 50% of elite high school athletes with echocardiographically confirmed normal hearts satisfied standard voltage criteria for ventricular hypertrophy. Pathological Q-waves, T-wave inversion or ST-segment depression were most helpful in distinguishing adolescents with HCM from normals. Both ESC and Seattle criteria successfully stratified the student-athlete and HCM cohorts, however each had a false-negative rate >10% for the HCM cohort. The Seattle criteria demonstrated a significantly lower false-positive rate (1%) than the ESC criteria (24%).

Radiofrequency Ablation in the Sinus of Valsalva for Ventricular Arrhythmia in Pediatric Patients.

The need to perform catheter ablation of ventricular arrhythmia from within the sinuses of Valsalva in a pediatric patient is uncommon. This has been reported in adults, but there are little data about the feasibility, safety or efficacy of catheter ablation in the sinuses of Valsalva in the pediatric patients. This is a retrospective review of all patients aged 18 years or less, at two separate institutions with no structural heart disease that underwent an ablation procedure for ventricular arrhythmia mapped to the sinus of Valsalva from 2010 to 2015. We identified 8 total patients meeting inclusion criteria. Median age was 16 years and the median weight was 61 kg. All patients were symptomatic or had developed arrhythmia-induced ventricular dysfunction. Ablation was performed in the left sinus in 4 patients and the right sinus in 4 patients. No ablations were required in the non-coronary sinus. All 8 patients had an acutely successful ablation using radiofrequency energy. There were no complications. At a mean follow-up of 7 months (4-15 months), all patients were known to be living. Follow-up data regarding arrhythmia were available in 6 of the 8 patients, and none had recurrence of their ventricular arrhythmia off of all antiarrhythmic medications. Radiofrequency catheter ablation of ventricular arrhythmia in the sinus of Valsalva can be done safely and effectively in pediatric patients.

Sudden cardiac arrest during sex in patients with either catecholaminergic polymorphic ventricular tachycardia or long-QT syndrome: a rare but shocking experience.

BACKGROUND: Patients with catecholaminergic polymorphic ventricular tachycardia (CPVT) and long-QT syndrome (LQTS) are susceptible to cardiac events during sympathetic nervous system activation. Herein, we sought to determine the risk of cardiac events associated with sex in CPVT and LQTS patients. METHODS AND RESULTS: We reviewed the electronic medical record of patients seen in the Genetic Heart Rhythm Clinic. There were 445 patients ≥ 18 years diagnosed with LQTS (N = 402, age at diagnosis 30 ± 16 years) or CPVT (N = 43, age at diagnosis 25 ± 15 years). No sex-induced cardiac events occurred in the LQTS population, and 2 occurred in the CPVT population. Sex-induced events were more likely in CPVT (2/43, 4.7%) than LQTS (0/402, 0%, P = 0.008). One case involved a 22-year-old CPVT1 female with prior cardiac arrest, who experienced several appropriate implantable cardioverter defibrillator shocks during intercourse while taking ß-blockers. The second case was a 52-year-old CPVT1 male with history of recurrent exercise-triggered syncope, who had syncope during sex in the setting of ß-blocker noncompliance. Extrapolating from published estimates of intercourse frequency by age, the overall event rate was only 0.0004%, and 0.005% among the CPVT cohort. CONCLUSIONS: Potentially life-threatening cardiac events during sex in patients with CPVT are rare and even rarer in LQTS. Overall, the cardiac event per intercourse rate is extremely low. Patients and their partners should be reassured that sex is a low-risk activity from a cardiac standpoint.