Mitral annular disjunction and mitral valve prolapse extrapolating adult data to an adolescent cohort?

PURPOSE OF REVIEW: The aim of this study is to provide an update on mitral valve prolapse (MVP) and mitral annular disjunction (MAD) and who may be at risk for ventricular arrhythmias and sudden cardiac death. RECENT FINDINGS: MVP is generally considered a benign condition. However, a small subset of patients may be at risk for life-threatening ventricular arrhythmias. Among the risk factors identified in adults include patients with bileaflet mitral valves, myxomatous changes, myocardial fibrosis, and the presence of MAD. Advances in multimodal imaging have allowed for improved identification of fibrosis, anatomical valve derangements, and the amount of MAD. Recent guidelines have suggested that patients with MVP with or without MAD may be at risk for life-threatening arrhythmias if they have had prior ventricular arrhythmias, ventricular dysfunction, or unexplained syncope. Yet, extrapolation of adult data to a pediatric cohort with similar MVP and MAD at this juncture is challenging. There is, however, early evidence that some pediatric patients with significant myocardial fibrosis or abnormal tissue Doppler may be at risk for ventricular tachycardia. SUMMARY: Mitral valve prolapse and mitral annular disjunction at times coexist and at other times can be seen as isolated entities. While the incidence of arrhythmic MVP is quite rare, there is increasing evidence that certain select adults with MVP may be at risk for ventricular tachycardia and sudden cardiac death. Future multicenter studies are needed to better understand the natural history of arrhythmic mitral valve disease and how early disease manifestation in children may impact findings now being reported in young adults.

Multiple recurrent supraventricular tachycardia in infantile tuberous sclerosis complex: management requiring triple-drug therapy.

We report the case of a female neonate admitted to the neonatal ICU with a rapid, narrow-complex tachyarrhythmia determined to be supraventricular tachycardia. Multimodality imaging and genetic testing confirmed a diagnosis of tuberous sclerosis complex with multiple cardiac rhabdomyomas. At 13 days of age, the patient was readmitted, exhibiting recurrent supraventricular tachycardia non-responsive to first-line treatment. Management required triple-drug therapy, whereafter the patient remained stable without recurrences. This is a rare report of supraventricular tachycardia in a functionally normal heart with the occurrence of supraventricular tachycardia due to structural abnormalities, with the possibility of multiple concealed accessory pathways.

Building resilient heart center teams.

PURPOSE OF REVIEW: The purpose of this review is to move beyond measures to improve individual resilience but to focus on measures to achieve better team resilience. RECENT FINDINGS: The COVID pandemic, shortages of heath care workers, and subsequent viral resurgence in 2022 placed tremendous stress on pediatric healthcare systems. Much has been written about individual wellness, mindfulness, and strategies to be a more resilient individual. However, little has been written on the importance of team resilience. Resilient teams work together to overcome daily stressors and challenges. Although leaders must create and foster a collaborative culture to establish cohesive and resilient teams; it also requires tremendous institutional support. Four key factors have emerged with regards to successful team resilience: candor, humility, resourcefulness, and compassion and empathy. This article discusses the key elements required for resilient teams to not only survive but also to thrive. SUMMARY: Effective heart centers, like the symphony, are a collection of individuals all coming together to care for a child or create a singular piece of music. Heart centers without effective leaders will most certainly fail, but even with the most accomplished and passionate leaders, there must be administrative institutional support and a shared vision.

Advocacy at the Eighth World Congress of Pediatric Cardiology and Cardiac Surgery.

The Eighth World Congress of Pediatric Cardiology and Cardiac Surgery (WCPCCS) will be held in Washington DC, USA, from Saturday, 26 August, 2023 to Friday, 1 September, 2023, inclusive. The Eighth World Congress of Pediatric Cardiology and Cardiac Surgery will be the largest and most comprehensive scientific meeting dedicated to paediatric and congenital cardiac care ever held. At the time of the writing of this manuscript, The Eighth World Congress of Pediatric Cardiology and Cardiac Surgery has 5,037 registered attendees (and rising) from 117 countries, a truly diverse and international faculty of over 925 individuals from 89 countries, over 2,000 individual abstracts and poster presenters from 101 countries, and a Best Abstract Competition featuring 153 oral abstracts from 34 countries. For information about the Eighth World Congress of Pediatric Cardiology and Cardiac Surgery, please visit the following website: [www.WCPCCS2023.org]. The purpose of this manuscript is to review the activities related to global health and advocacy that will occur at the Eighth World Congress of Pediatric Cardiology and Cardiac Surgery.Acknowledging the need for urgent change, we wanted to take the opportunity to bring a common voice to the global community and issue the Washington DC WCPCCS Call to Action on Addressing the Global Burden of Pediatric and Congenital Heart Diseases. A copy of this Washington DC WCPCCS Call to Action is provided in the Appendix of this manuscript. This Washington DC WCPCCS Call to Action is an initiative aimed at increasing awareness of the global burden, promoting the development of sustainable care systems, and improving access to high quality and equitable healthcare for children with heart disease as well as adults with congenital heart disease worldwide.

Arrhythmogenic right ventricular cardiomyopathy in the pediatric population.

PURPOSE OF REVIEW: Review the current state of the art of arrhythmogenic right ventricular cardiomyopathy (ARVC) diagnosis and risk stratification in the pediatric population. RECENT FINDINGS: ARVC is an inherited cardiomyopathy characterized by progressive myocyte loss and fibrofatty replacement of predominantly the right ventricle and high risk of ventricular arrhythmias and sudden cardiac death (SCD). ARVC is one of the leading causes of arrhythmic cardiac arrest in young people. Early diagnosis and accurate risk assessment are challenging, especially in children who often exhibit little to no phenotype, even if genotype positive. Multimodal imaging provides more detailed assessment of the right ventricle and has been shown in pediatric patients to identify earlier preclinical disease expression. Identification of patients with ARVC allows the clinician to intervene early with appropriate exercise restrictions, even if genotype positive only without phenotypic expression. Emphasis should be placed on stratifying the patient's risk of ventricular arrhythmias and SCD. SUMMARY: ARVC is a challenging diagnosis to make in adolescents who often do not exhibit clinical symptoms. Newer multimodal imaging techniques and improvements in genetic testing and biomarkers should help improve early diagnosis. Exercise restriction for children with ARVC has been shown to reduce disease advancement and decreases the risk of a life-threatening event.

The history of cardiac pacing in the young and a look to the future.

PURPOSE OF REVIEW: The purpose of this review is to explore the historical and serendipitous events that led to the creation of modern-day pacemakers. In addition, this review will explore how contemporary conduction site-specific pacing has overcome some of the deleterious effects from historical chronic right ventricular apical pacing. RECENT FINDINGS: Recently, there have been tremendous advances in not just the lead design but the tools required to promote more physiologic pacing. Although cardiac resynchronization pacing has been around for nearly 2 decades, this review also introduces and discusses the early results of His-bundle pacing and left bundle branch pacing and some of the potential applicability of this technology for our children. SUMMARY: Pacemakers have evolved significantly in the last 30 years through collaborative partnerships between physicians and engineers. The future of cardiac pacing is bright compared to the field of electrotherapy 50 years ago. Future iterations of pacemakers must consider unusual anatomy and growing children. Pediatric patients contribute to a small percentage of the overall device volume, but the majority of these patients will have a pacemaker for life. We need to be proactive and consider what are the best short and long-term solutions for this cohort.

Long QT and Hearing Loss in High-Risk Infants Prospective Study Registry.

The objective of this study is to determine the prevalence of an abnormal electrocardiogram showing a prolonged QTc greater than 450 ms in infants with unilateral or bilateral sensorineural hearing loss. We conducted a prospective study of healthy term infants (≥37 weeks gestational age) who failed their newborn auditory brainstem response hearing screen, were seen by an audiologist and diagnosed as having sensorineural hearing loss during follow-up to 1 year of age. In infants with a diagnosis of hearing loss, we collected a detailed family history and performed an ECG between 2 and 6 months of age. We obtained follow-up for 1 year by calling the parent requesting the hearing and cardiac status of their child. Two of the 40 infants with sensorineural hearing loss (5%) had a QTc greater than 450 ms. Both had mild bilateral hearing loss and genetic testing did not identify a known mutation for long QT syndrome. The remaining 38 infants had QTc intervals of ≤ 450 ms. One patient diagnosed with bilateral severe sensorineural hearing loss had a normal ECG (QTc = 417 ms). Several months after the ECG was performed, the infant's mother contacted the study cardiologist after she learned that the infant's maternal grandmother was diagnosed with a cardiomyopathy and arrhythmias. Genetic testing was recommended even though the child was asymptomatic and was positive for a pathogenic mutation in the KCNQ1 gene. We speculate that molecular genetic testing in infants with hearing loss may become the standard of care rather than targeted electrocardiograms.Clinical Trial Registration NCT02082431 https://www.clinicaltrials.gov/ct2/show/NCT02692521?cond=NCT02692521&rank=1 .

Preliminary assessment of paediatric electrophysiology cardiac implantable electronic device resources around the world.

BACKGROUND: The Pediatric and Congenital Electrophysiology Society (PACES) is a global organisation committed to the care of children and adults with CHD and arrhythmias. OBJECTIVE: To evaluate the global needs and potential inequities as it relates to cardiac implantable electronic devices. METHODS: ARROW (Assessment of Rhythm Resources arOund the World) is an online survey about cardiac implantable electronic devices, sent electronically to physicians within the field of Cardiology, Pediatric Cardiology, Electrophysiology and Pediatric Electrophysiology. RESULTS: ARROW received 42 responders from 28 countries, 50% from low-/middle-income regions. The main differences between low-/middle- and high-income regions include availability of expertise on paediatric electrophysiology (50% versus 93%, p < 00.5) and possibility to perform invasive procedures (35% versus 93%, p < 0.005). Implant of devices in low-income areas relies significantly on patient's resources (71%). The follow-up of the devices is on the hands of paediatric cardiologist/electrophysiologist in higher resources centres (93% versus 50%, p < 0.05). CONCLUSIONS: The ARROW survey represents an initial assessment of the geographical characteristics in the field of Pediatric Electrophysiology. The next step is to make this "state of the art" more extensive to other aspects of the expertise. The relevance of collecting this data before the World Congress of Pediatric Cardiology and Cardiac Surgery (WCPCCS) in 2023 in Washington DC was emphasised in order to share the resulting information with the international community and set a plan of action to assist the development of arrhythmia services for children within developing regions of the world.

COVID-19 will forever change the landscape of telemedicine.

PURPOSE OF REVIEW: The COVID-19 pandemic has had unprecedented global effects, yet the rapid emergence of telehealth across the globe has allowed healthcare professionals to connect virtually with patients and families while following safe social distancing guidelines. Telehealth has been used relatively well in patients from remote regions with limited access to subspecialty healthcare providers. This article discusses novel ways of using telehealth during the current pandemic and measures that would need to be taken to sustain telehealth and teleconsultations. RECENT FINDINGS: Telehealth has expanded to outpatient pediatric cardiology clinics across the globe during the pandemic. Technological advancements in video conferencing and the abundance of readily available wearable devices have allowed cardiologists to establish a preliminary diagnosis and set forth a treatment plan. Additional support by insurance providers and relaxation of mandatory regulations by the government have allowed telehealth to succeed during the pandemic. Although many subdisciplines within pediatric cardiology can be easily adapted into a sustainable telehealth model, some unique patient interactions, such as fetal cardiology, exercise physiology, and echocardiograms cannot be done remotely. The field of telehealth medicine with HIPAA-compliant programs and both insurance and government support should remain in our armamentarium of available resources for all patients and families. SUMMARY: Although not unique to pediatric cardiology, telehealth has emerged as an avenue to perform an initial evaluation and even establish a care pathway for patients. It is well recognized that telehealth visits will not supplant all patient--physician interactions but is a very acceptable first step in the majority of cases and can often steer the patient to subsequently undergo more selective and streamlined care.

Newer risk assessment strategies in hypertrophic cardiomyopathy.

PURPOSE OF REVIEW: The present article serves to review current risk assessment guidelines for sudden cardiac death (SCD) in patients with hypertrophic cardiomyopathy (HCM) and to discuss how these guidelines can be applied to patients with childhood HCM. New diagnostic techniques that could lead to more accurate risk assessment tools are also discussed. RECENT FINDINGS: Current guidelines for risk assessment in childhood HCM are extrapolated from adult guidelines and lack background research to validate their use. Continuous variables, such as wall thickness, are converted to binary variables, which is particularly concerning in pediatric patients' where weight gain and linear growth is likely to lead to more significant hemodynamic changes in shorter periods of time. Some studies have even shown that risk factors concerning in adults may actually be protective in pediatric patients. Additionally, large gaps still remain between genotype and phenotype expression in HCM. SUMMARY: A better understanding of the relationship between cause, phenotype, and outcomes is needed to truly be able to determine risk for SCD in childhood HCM. Larger studies, including newer technologies and quantitative models, similar to the European HCM Risk-SCD model, which allows for a quantitative risk diagnosis, are needed as well.

Challenge of managing opposing rhythms in a mother and fetus.

INTRODUCTION: We report a case of a fetus with complex congenital heart disease and supraventricular tachycardia in the setting of maternal high grade atrioventricular block at 26 weeks' gestation. METHODS AND RESULTS: Electroanatomic mapping allowed successful implantation of a permanent pacemaker to provide adequate back-up pacing in the mother with zero radiation exposure, thus allowing safe delivery of transplacental anti-arrhythmic medications to reduce the fetal arrhythmia burden and optimize the fetal ventricular rate. CONCLUSION: This is the first reported case of using electroanatomic mapping, with zero fluoroscopy use, for pacemaker lead placement and for a novel indication.

COVID-19-associated multisystem inflammatory syndrome in children presenting uniquely with sinus node dysfunction in the setting of shock.

SARS-CoV-2, which causes the disease COVID-19, generally has a mild disease course in children. However, a severe post-infectious inflammatory process known as multisystem inflammatory syndrome in children has been observed in association with COVID-19. This inflammatory process is a result of an abnormal immune response with similar clinical features to Kawasaki disease. It is well established that multisystem inflammatory syndrome in children is associated with myocardial dysfunction, coronary artery dilation or aneurysms, and occasionally arrhythmias. The most common electrocardiographic abnormalities seen include premature atrial or ventricular ectopy, variable degrees of atrioventricular block, and QTc prolongation, and rarely, haemodynamically significant arrhythmias necessitating extracorporeal membrane oxygenation support. However, presentation with fever, hypotension, and relative bradycardia with a left axis idioventricular rhythm has not been previously reported. We present a case of a young adolescent with multisystem inflammatory syndrome in children with myocarditis and a profoundly inappropriate sinus node response to shock with complete resolution following intravenous immunoglobulin.

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.

Ivabradine as a stabilising anti-arrhythmic agent for multifocal atrial tachycardia.

Multifocal atrial tachycardia has certain electrocardiographic similarities to atrial fibrillation. The mechanism of atrial fibrillation is heterogenous but in some cases may arise from a single ectopic driver with fibrillatory conduction to the rest of the atria. This has led to the speculation that multifocal atrial tachycardia may have a similar mechanistic unifocal site that disperses through the atrium in a fibrillatory pattern. Ivabradine has been reported to be efficacious in an adult with paroxysmal atrial fibrillation as well as in children with junctional or ectopic atrial tachycardias. This is the first report of successfully using ivabradine, a novel anti-arrhythmic If blocking agent, to convert multifocal atrial tachycardia in a 5-month-old critically ill infant to a pattern indicating a single ectopic atrial focus. This allowed the patient's single atrial focus to be ablated with return to sinus rhythm and decannulation from ventriculoarterial extracorporeal membrane oxygenation. This case suggests that multifocal atrial tachycardia may arise from a single automatic focus with downstream fibrillatory conduction to the atria.

Frequent premature ventricular beats in healthy children: when to ignore and when to treat?

PURPOSE OF REVIEW: Premature ventricular beats (PVCs) are frequently identified in healthy children with structurally normal hearts and generally have a benign clinical course often disappearing spontaneously. However, a small percentage of children may develop a cardiomyopathy. The purpose of this review is to understand which children may be at risk of development of left ventricular (LV) dysfunction with idiopathic PVCs. RECENT FINDINGS: There is increasing evidence that a ventricular ectopic burden more than 24% in adults may lead to LV dysfunction. Most of the pediatric studies to date are retrospective, small case series from single institutions and have conflicting results regarding a direct correlation of the PVC burden to LV dysfunction. Development of a cardiomyopathy from frequent PVCs in children is likely multifactorial relating to the burden itself, presence of higher levels of ectopy (couplets and runs of ventricular tachycardia) as well as the duration of ventricular ectopy. Understanding the duration of ectopy is often unknown as patients are asymptomatic and the irregular heart beat was identified at a well-child examination. SUMMARY: Asymptomatic children with normal ventricular function and a low ectopy burden can be followed without any intervention and generally reassured. Children with an ectopy burden more than 30% are at some risk of developing LV dysfunction and should be more closely followed with noninvasive imaging. Development of symptoms attributed to the ectopy or signs of increasing LV dimensions or LV dysfunction should be treated with medication or catheter ablation.

An unusual presentation of a large cardiac mass.

We present a case of a large left ventricular capillary haemangioma incidentally discovered in a pre-adolescent patient.

Challenges of healthcare administration: optimizing quality and value at an affordable cost in pediatric cardiology.

PURPOSE OF REVIEW: The purpose of this review is to explore the paradigm shift in healthcare delivery that will need to take place over the next few years away from an emphasis on supply-driven health care to better quality transparent-driven health care whose focus is on the consumer's best interest. RECENT FINDINGS: The current healthcare system is fragmented and costs continue to rise. The best way to contain costs is to improve quality to the consumer, the patient. Physicians and hospitals need to align in a team-based approach that allows physicians to understand current costs and how to strive toward a focus on healthcare outcomes. Pediatric cardiology is a unique discipline that cares for patients with complex congenital conditions that will span their lifetime and also involves not just cardiology but surgery, intensive care, anesthesia, nursing, and a host of inpatient and ambulatory services. Understanding what matters to the patient and his/her family and presenting quality outcomes in a transparent fashion will gradually allow a shift to take place away from physician visits, tests ordered, and procedures performed. This can only be achieved with physicians, given the appropriate tools to understand costs, value, and outcomes and models where the hospitals and physicians are aligned. SUMMARY: The transformation to a value-based healthcare system is beginning and pediatric cardiologists need to be educated, given the appropriate resources, receive appropriate feedback, and patients need to be part of the solution so that care providers can understand what matters most to them.

The clinical and genetic spectrum of catecholaminergic polymorphic ventricular tachycardia: findings from an international multicentre registry.

Aims: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an ion channelopathy characterized by ventricular arrhythmia during exertion or stress. Mutations in RYR2-coded Ryanodine Receptor-2 (RyR2) and CASQ2-coded Calsequestrin-2 (CASQ2) genes underlie CPVT1 and CPVT2, respectively. However, prognostic markers are scarce. We sought to better characterize the phenotypic and genotypic spectrum of CPVT, and utilize molecular modelling to help account for clinical phenotypes. Methods and results: This is a Pediatric and Congenital Electrophysiology Society multicentre, retrospective cohort study of CPVT patients diagnosed at <19 years of age and their first-degree relatives. Genetic testing was undertaken in 194 of 236 subjects (82%) during 3.5 (1.4-5.3) years of follow-up. The majority (60%) had RyR2-associated CPVT1. Variant locations were predicted based on a 3D structural model of RyR2. Specific residues appear to have key structural importance, supported by an association between cardiac arrest and mutations in the intersubunit interface of the N-terminus, and the S4-S5 linker and helices S5 and S6 of the RyR2 C-terminus. In approximately one quarter of symptomatic patients, cardiac events were precipitated by only normal wakeful activities. Conclusion: This large, multicentre study identifies contemporary challenges related to the diagnosis and prognostication of CPVT patients. Structural modelling of RyR2 can improve our understanding severe CPVT phenotypes. Wakeful rest, rather than exertion, often precipitated life-threatening cardiac events.