A Single-center Experience Comparing First- Versus Second-generation Insertable Cardiac Monitors in Pediatric Patients.

Insertable cardiac monitors (ICMs) have undergone advancements in size and functionality over the past decade, resulting in the introduction of small, easily insertable devices capable of long-term remote monitoring. We define first-generation ICMs as implantable cardiac monitoring devices that require an incision and surgical creation of a subcutaneous pocket and second-generation ICMs as devices implanted using a custom-made tool for subcutaneous insertion, respectively. The aim of this study was to understand the differences between first- and second-generation pediatric ICM implants, implant indications, and time to diagnosis. We performed a retrospective, single-center chart review of patients who underwent ICM implantation from 2009-2019, spanning a 5-year course of first-generation ICM implantations and 5-year course of second-generation ICM implantations. Demographic data, past medical history, implant indication, and time to diagnosis were obtained. A total of 208 patients were identified over the 10-year time period, including 38 (18%) who underwent implantation with a first-generation device and 170 (82%) who underwent implantation with a second-generation device. Implant indications for first-generation ICMs included syncope (71%), palpitations (16%), inherited arrhythmia syndrome (IAS) management (5%), and premature ventricular contractions/ventricular tachycardia (VT) (8%); implant indications for second-generation ICMs included syncope (48%), palpitations (19%), IAS management (40%), premature ventricular contractions/VT (11%), atrial fibrillation (2%), tachycardia (3%), and heart block (0.5%). The average time to diagnosis was 38 weeks for patients with first-generation devices and 55 weeks for those with second-generation devices. With innovations in ICM technologies, there are expanding indications for ICM implantation in pediatric patients for long-term monitoring, specifically regarding the management of IAS patients.

Familial Recurrence Patterns in Congenitally Corrected Transposition of the Great Arteries: An International Study.

BACKGROUND: Congenitally corrected transposition of the great arteries (ccTGA) is a rare disease of unknown cause. We aimed to better understand familial recurrence patterns. METHODS: An international, multicentre, retrospective cohort study was conducted in 29 tertiary hospitals in 6 countries between 1990 and 2018, entailing investigation of 1043 unrelated ccTGA probands. RESULTS: Laterality defects and atrioventricular block at diagnosis were observed in 29.9% and 9.3%, respectively. ccTGA was associated with primary ciliary dyskinesia in 11 patients. Parental consanguinity was noted in 3.4% cases. A congenital heart defect was diagnosed in 81 relatives from 69 families, 58% of them being first-degree relatives, including 28 siblings. The most prevalent defects in relatives were dextro-transposition of the great arteries (28.4%), laterality defects (13.6%), and ccTGA (11.1%); 36 new familial clusters were described, including 8 pedigrees with concordant familial aggregation of ccTGA, 19 pedigrees with familial co-segregation of ccTGA and dextro-transposition of the great arteries, and 9 familial co-segregation of ccTGA and laterality defects. In one family co-segregation of ccTGA, dextro-transposition of the great arteries and heterotaxy syndrome in 3 distinct relatives was found. In another family, twins both displayed ccTGA and primary ciliary dyskinesia. CONCLUSIONS: ccTGA is not always a sporadic congenital heart defect. Familial clusters as well as evidence of an association between ccTGA, dextro-transposition of the great arteries, laterality defects and in some cases primary ciliary dyskinesia, strongly suggest a common pathogenetic pathway involving laterality genes in the pathophysiology of ccTGA.

Implementation and early experience of a pediatric electrophysiology telehealth program.

Background: Telehealth (TH) visits have been growing with exponential increased utilization during the COVID-19 pandemic. The aim of this manuscript is to describe the implementation and early experience of a pediatric electrophysiology (EP) TH program implemented during the pandemic, assessing patient satisfaction, patient equity and inclusion (measured by geographical outreach), and sustainability. Methods: A retrospective chart review study was performed and data were collected from the medical record, including demographic, testing, and billing data from scheduled TH encounters between March and August 2020 of a single pediatric EP group in the Midwest. Patients were called to complete satisfaction surveys. Results: Patients with diverse pathologies were seen in TH, with supraventricular/atrial tachycardias (n = 41, 35%) and inherited arrhythmia syndromes (n = 23, 20%) being most common. The mean distance from clinic was 95 miles (range 2.8-320 miles), with 43% of patients living more than 100 miles away from clinic. A total of 172 tests were performed previsit (n = 102, 59%), during the visit (n = 17, 10%), or postvisit (n = 53, 31%), including 15 EP studies. Time-based Current Procedural Terminology codes were predominantly used for billing purposes (n = 92, 78%). There was generation of work relative value units (wRVU) for visits (220.5 wRVU) and testing (325.1 wRVU). Survey data demonstrated that 98% of patients were satisfied with their telehealth appointment and 99% had a clear understanding of their diagnosis. Conclusion: Pediatric EP TH clinics can provide care for a geographically and pathologically heterogeneous group of patients who had positive attitudes toward TH. Our study shows significant downstream testing and subsequent wRVU generation, suggesting financial sustainability.

The Evolution of Pediatric and Congenital Electrophysiology as a Subspecialty.

Over the past 50 years, pediatric and congenital electrophysiology has progressed from a rare subspecialty practiced at just a handful of centers to become an essential part of nearly every congenital heart program the world over. This paper traces the evolution of the subspecialty in North America by recognizing the individuals who dedicated their careers to this field and trained subsequent generations of practitioners, thereby establishing a legacy that insures continued progress in the treatment of arrhythmias for children and patients with congenital heart disease. Data were generated from a survey of the current membership of the Pediatric and Congenital Electrophysiology Society and were supplemented by review of archived Society records. Maps depicting the locations for clinicians and training centers over time provide a graphic display of progress in this field.

Opportunities and challenges in heart rhythm research: Rationale and development of an electrophysiology collaboratory.

There are many challenges in the current landscape of electrophysiology (EP) clinical and translational research, including increasing costs and complexity, competing demands, regulatory requirements, and challenges with study implementation. This review seeks to broadly discuss the state of EP research, including challenges and opportunities. Included here are results from a Heart Rhythm Society (HRS) Research Committee member survey detailing HRS members' perspectives regarding both barriers to clinical and translational research and opportunities to address these challenges. We also provide stakeholder perspectives on barriers and opportunities for future EP research, including input from representatives of the U.S. Food and Drug Administration, industry, and research funding institutions that participated in a Research Collaboratory Summit convened by HRS. This review further summarizes the experiences of the heart failure and heart valve communities and how they have approached similar challenges in their own fields. We then explore potential solutions, including various models of research ecosystems designed to identify research challenges and to coordinate ways to address them in a collaborative fashion in order to optimize innovation, increase efficiency of evidence generation, and advance the development of new therapeutic products. The objectives of the proposed collaborative cardiac EP research community are to encourage and support scientific discourse, research efficiency, and evidence generation by exploring collaborative and equitable solutions in which stakeholders within the EP community can interact to address knowledge gaps, innovate, and advance new therapies.

Assessment of Apple Watch Series 6 pulse oximetry and electrocardiograms in a pediatric population.

BACKGROUND: Recent technologic advances have resulted in increased development and utilization of direct-to-consumer cardiac wearable devices with various functionality. This study aimed to assess Apple Watch Series 6 (AW6) pulse oximetry and electrocardiography (ECG) in a cohort of pediatric patients. METHODS: This single-center, prospective study enrolled pediatric patients ≥ 3kg and having an ECG and/or pulse oximetry (SpO2) as part of their planned evaluation. Exclusion criteria: 1) non-English speaking patients and 2) patients in state custody. Simultaneous tracings were obtained for SpO2 and ECG with concurrent standard pulse oximeter and 12-lead ECG. AW6 automated rhythm interpretations were compared to physician over-read and categorized as accurate, accurate with missed findings, inconclusive (automated interpretation: "inconclusive"), or inaccurate. RESULTS: A total of 84 patients were enrolled over a 5-week period. 68 patients (81%) were placed into the SpO2 and ECG arm, with 16 patients (19%) placed into the SpO2 only arm. Pulse oximetry data was successfully collected in 71/84 (85%) patients and ECG data in 61/68 (90%). ΔSpO2 between modalities was 2.0±2.6% (r = 0.76). ΔRR was 43±44msec (r = 0.96), ΔPR 19±23msec (r = 0.79), ΔQRS 12±13msec (r = 0.78), and ΔQT 20±19msec (r = 0.9). The AW6 automated rhythm analysis yielded a 75% specificity and found: 1) 40/61 (65.6%) "accurate", 2) 6/61 (9.8%) "accurate with missed findings", 3) 14/61 (23%) "inconclusive", and 4) 1/61 (1.6%) incorrect. CONCLUSION: The AW6 can accurately measure oxygen saturation when compared to hospital pulse oximeters in pediatric patients and provide good quality single lead ECGs that allow for accurate measurement of RR, PR, QRS, and QT intervals with manual interpretation. The AW6-automated rhythm interpretation algorithm has limitations for smaller pediatric patients and patients with abnormal ECGs.

A unique cardiovascular presentation of pheochromocytoma.

We describe a unique presentation of a pheochromocytoma in a normotensive teenager, who presented with symptoms of headache, neck pain, and palpitations. Holter and event monitor tracings revealed intermittent junctional rhythm causing electromechanical dyssynchrony between atrial and ventricular contraction resulting in reported symptoms. Exercise stress testing helped correlate symptomatic junctional rhythm events to episodic hypertension which led to the eventual diagnosis of pheochromocytoma. The exercise test provided insight into the physiologic coupling that the sympathetic and parasympathetic autonomic nervous systems have on the cardiovascular system during exercise and exaggerated hypertension. The patient was found to have MEN2A and partial adrenalectomy resulted in complete resolution of symptoms and arrhythmia. This unusual presentation illustrates the benefit of a comprehensive clinical evaluation, which led to the eventual diagnosis.

Preventing Arrhythmic Death in Patients With Tetralogy of Fallot: JACC Review Topic of the Week.

Patients with tetralogy of Fallot are at risk for ventricular arrhythmias and sudden cardiac death. These abnormalities are associated with pulmonary regurgitation, right ventricular enlargement, and a substrate of discrete, slowly-conducting isthmuses. Although these arrhythmic events are rare, their prediction is challenging. This review will address contemporary risk assessment and prevention strategies. Numerous variables have been proposed to predict who would benefit from an implantable cardioverter-defibrillator. Current risk stratification models combine independently associated factors into risk scores. Cardiac magnetic resonance imaging, QRS fragmentation assessment, and electrophysiology testing in selected patients may refine some of these models. Interaction between right and left ventricular function is emerging as a critical factor in our understanding of disease progression and risk assessment. Multicenter studies evaluating risk factors and risk mitigating strategies such as pulmonary valve replacement, ablative strategies, and use of implantable cardiac-defibrillators are needed moving forward.

Performance Evaluation of Mixed Reality Display for Guidance During Transcatheter Cardiac Mapping and Ablation.

Cardiac electrophysiology procedures present the physician with a wealth of 3D information, typically presented on fixed 2D monitors. New developments in wearable mixed reality displays offer the potential to simplify and enhance 3D visualization while providing hands-free, dynamic control of devices within the procedure room. OBJECTIVE: This work aims to evaluate the performance and quality of a mixed reality system designed for intraprocedural use in cardiac electrophysiology. METHOD: The Enhanced Electrophysiology Visualization and Interaction System (ELVIS) mixed reality system performance criteria, including image quality, hardware performance, and usability were evaluated using existing display validation procedures adapted to the electrophysiology specific use case. Additional performance and user validation were performed through a 10 patient, in-human observational study, the Engineering ELVIS (E2) Study. RESULTS: The ELVIS system achieved acceptable frame rate, latency, and battery runtime with acceptable dynamic range and depth distortion as well as minimal geometric distortion. Bench testing results corresponded with physician feedback in the observational study, and potential improvements in geometric understanding were noted. CONCLUSION: The ELVIS system, based on current commercially available mixed reality hardware, is capable of meeting the hardware performance, image quality, and usability requirements of the electroanatomic mapping display for intraprocedural, real-time use in electrophysiology procedures. Verifying off the shelf mixed reality hardware for specific clinical use can accelerate the adoption of this transformative technology and provide novel visualization, understanding, and control of clinically relevant data in real-time.

Institutional experience of healthy pediatric patients presenting with atrial fibrillation who had an electrophysiology study.

INTRODUCTION: Atrial fibrillation (AF) is a very common tachyarrhythmia with increasing prevalence with age, but uncommon in the pediatric population. Understanding that AF increases comorbidities make the need for investigation and potential elimination of alternate etiologies in pediatric AF patients critical. The objective of this study was to review our institutional data and compare our findings with previously documented adult AF risk factors to pediatric patients while also identifying which patients had alternate electrophysiology diagnoses amenable to transcatheter ablation. METHODS: A retrospective chart review was performed identifying AF patients who were less than 21 years old, had no significant congenital cardiovascular anomalies, a documented episode of AF on electrocardiogram and underwent invasive electrophysiology study (EPS). RESULTS: Nineteen patients were identified over a 9-year period of time finding a male predominance (74%), the average age of 14.95 ± 4.17 years, the average weight of 78.5 ± 31.4 kg, and average body mass index of 26.8 ± 6.87 kg/m2 . Preprocedural left atrial volumes made on echocardiograms demonstrated a mean of 33.96 ± 16.35 mL/m2 (Z-scores -0.81 ± 1.50), indicating no dilation. Five of nineteen patients (26%) had additional electrophysiologic diagnoses during EPS, including atrioventricular reentrant tachycardia (n = 2, 10%) and atrioventricular nodal reentrant tachycardia (n = 3, 16%). Four patients underwent successful ablation with no documented or clinical AF recurrence. CONCLUSIONS: Adult risk factors of male predominance and obesity were seen in pediatric AF patients, while left atrial enlargement was not. Twenty-one percent of the pediatric AF patients who had additional electrophysiologic substrates and successful ablations resulted in no further clinical episodes of AF. This suggests that pediatric patients presenting with AF might benefit from an EPS as part of a complete evaluation.

Challenges in Ablation of Complex Congenital Heart Disease.

The field of congenital cardiac electrophysiology is growing rapidly due to the rapid growth in the population of survivors of childhood critical congenital heart disease surgery. Chronic arrhythmias pose one of the biggest challenges in this patient population, and catheter ablation, despite its challenges, is still the most desirable and acceptable approach when successful. Clinicians who propose catheter ablation in such patients need to understand the congenital anatomy, should carefully review the details of all prior cardiac surgery, and should be prepared to deal with the various challenges posed by lack of normal cardiac access and the possibility of poor hemodynamics. Still, experienced laboratories can achieve excellent results in this difficult patient population.