Epicardial vs. transvenous implantable cardioverter defibrillators in children

Cardiac implantable electronic devices in pediatric and congenital populations

Pediatric patients and children and adults with congenital heart disease often will require implantation of cardiac implantable electronic devices (CIEDs) for management of a variety of cardiac rhythm pathologies. The safe and effective use of CIEDs in these patients requires an awareness of important differences between this special population and the adult populations for whom these devices were primarily developed and in whom they have been most thoroughly studied. These include issues of body size and growth, anticipated lifespan, anatomical issues related to implantation and the epidemiology of underlying rhythm issues. In this paper, we discuss these issues in the context of the current state of the art in pediatric and congenital heart disease patients with respect to implant and lead extraction strategies, physiological cardiac pacing and resynchronization, ICD indications and use of transvenous and subcutaneous devices, and the use of implantable monitoring devices.

HRS Call to Action: Improved MRI Access for Patients with Cardiovascular Implantable Electronic Devices

Access to magnetic resonance imaging (MRI) remains limited for many patients with cardiovascular implantable electronic devices (CIEDs), despite evidence demonstrating safety under appropriate conditions. This call-to-action statement from the Heart Rhythm Society (HRS) aims to describe persistent barriers to MRI access for patients with a CIED and to provide practical, actionable recommendations for improvement of clinical care. Developed by a multidisciplinary writing committee, this document addresses regulatory, operational, and institutional challenges; highlights findings from a recent HRS member survey on MRI access; and outlines the impact of evolving vendor-specific MRI exclusions. Specific populations discussed include patients with multiple MRI-conditional devices, mixed-vendor systems, abandoned leads, and epicardial leads or subcutaneous arrays. The statement also calls attention to the clinical and administrative burden on electrophysiology teams and the need for fair recognition and reimbursement of MRI-related care. Collaboration across specialties, industry, and regulatory bodies is essential to eliminate non-data-driven barriers and to ensure equitable access to clinically indicated MRI for all patients with a CIED.

Independent External Evaluation of Pediatric Hypertrophic Cardiomyopathy Risk Scores in Predicting Severe Ventricular Arrhythmias

BACKGROUND

Sudden cardiac death is the most common cause of death in childhood hypertrophic cardiomyopathy (HCM). Recently, 2 risk scores have been developed to estimate the 5-year risk of sudden cardiac death. We aimed to assess their respective performances in an independent cohort.

METHODS

All patients with HCM aged <18 years from a single center were retrospectively included between 2003 and 2023. HCM Risk-Kids and PRIMaCY risk scores were calculated at diagnosis and during follow-up. The primary composite outcome included sustained ventricular arrhythmia, appropriate implantable cardioverter defibrillator (ICD) therapy, aborted cardiac arrest, or sudden cardiac death.

RESULTS

A total of 100 primary prevention children were included (7.1±5.6 years, 59.0% males), with a mean follow-up of 8.6±5.5 years. Overall, 13 (13.0%) patients experienced the primary composite outcome. When only considering events during the 5 first years, Harrel C index was 0.52 (95% CI, 0.27-0.77) for HCM Risk-Kids (≥6%) and 0.70 (95% CI, 0.59-0.80) for PRIMaCY (>8.3%), with 1 patient potentially treated by ICD for every 25 ICDs implanted for HCM Risk-Kids and 1 for every 14 ICDs implanted for PRIMaCY. When risk scores were repeated and all primary outcomes during follow-up were considered, 12 of 13 (92.3%) events were correctly identified using both risk scores, with 1 patient potentially treated by ICD for every 5.6 ICDs implanted for HCM Risk-Kids and 1 for every 5.3 ICDs implanted for PRIMaCY. Among 44 (44.0%) patients implanted with an ICD, all primary prevention patients who had ≥1 appropriate ICD therapy during follow-up had an HCM Risk-Kids ≥6% and PRIMaCY >8.3% at implantation.

CONCLUSIONS

In this independent evaluation, our findings suggest imperfect discrimination between low and high-risk patients using the HCM Risk-Kids and PRIMaCY risk scores, with predicted risks tending to be overestimated compared with the actual observed events. The performance or risk scores was substantially improved by periodic reassessment during follow-up.

Implantable cardioverter defibrillator therapy in paediatric patients for primary vs. secondary prevention

AIMS

The decisions about placing an ICD in a child are more difficult than in an adult due to longer expected lifespan and the complication risk. Young patients gain the most years from ICDs, despite higher risk of device-related complications. The secondary prevention ICD indication is clear, and device is implanted regardless of potential complications. For primary prevention, risk of sudden cardiac death and complications need to be evaluated. We aimed to compare outcomes for primary and secondary prevention ICDs.

METHODS AND RESULTS

Retrospective nationwide cohort study including paediatric patients identified from the Danish ICD registry with ICD implanted at an age ≤ 15 from 1982-21. Demographics, complications (composite of device-related infections or lead-failure requiring re-operation, mortality because of arrhythmia, or unknown cause), and mortality were retrieved from medical charts. Endpoint was appropriate therapy (shock or anti-tachycardia pacing for ventricular tachycardia or fibrillation). Of 72 receiving an ICD, the majority had channelopathies (n = 34) or structural heart diseases (n = 28). ICDs were implanted in 23 patients for primary prevention and 49 for secondary prevention, at median ages of 13.8 and 11.6 years (P-value 0.01), respectively. Median follow-up was 9.0 (interquartile ranges: 4.7-13.5) years. The 10-year cumulative incidence of first appropriate therapy was 70%, with complication and inappropriate therapy rates at 41% and 15%, respectively. No difference was observed between prevention groups for all outcomes. Six patients died during follow-up.

CONCLUSION

In children, two-thirds are secondary prevention ICDs. Children have higher appropriate therapy and complication rates than adults, while the inappropriate therapy rate was low.

Congenital Long QT Syndrome in Children and Adolescents: A General Overview

Congenital long QT syndrome (LQTS) represents a disorder of myocardial repolarization characterized by a prolongation of QTc interval on ECG, which can degenerate into fast polymorphic ventricular arrhythmias. The typical symptoms of LQTS are syncope and palpitations, mainly triggered by adrenergic stimuli, but it can also manifest with cardiac arrest. At least 17 genotypes have been associated with LQTS, with a specific genotype-phenotype relationship described for the three most common subtypes (LQTS1, -2, and -3). β-Blockers are the first-line therapy for LQTS, even if the choice of the appropriate patients needing to be treated may be challenging. In specific cases, interventional measures, such as an implantable cardioverter-defibrillator (ICD) or left cardiac sympathetic denervation (LCSD), are useful. The aim of this review is to highlight the current state-of-the-art knowledge on LQTS, providing an updated picture of possible diagnostic algorithms and therapeutic management.

New Guidelines of Pediatric Cardiac Implantable Electronic Devices: What Is Changing in Clinical Practice?

Guidelines are important tools to guide the diagnosis and treatment of patients to improve the decision-making process of health professionals. They are periodically updated according to new evidence. Four new Guidelines in 2021, 2022 and 2023 referred to pediatric pacing and defibrillation. There are some relevant changes in permanent pacing. In patients with atrioventricular block, the heart rate limit in which pacemaker implantation is recommended was decreased to reduce too-early device implantation. However, it was underlined that the heart rate criterion is not absolute, as signs or symptoms of hemodynamically not tolerated bradycardia may even occur at higher rates. In sinus node dysfunction, symptomatic bradycardia is the most relevant recommendation for pacing. Physiological pacing is increasingly used and recommended when the amount of ventricular pacing is presumed to be high. New recommendations suggest that loop recorders may guide the management of inherited arrhythmia syndromes and may be useful for severe but not frequent palpitations. Regarding defibrillator implantation, the main changes are in primary prevention recommendations. In hypertrophic cardiomyopathy, pediatric risk calculators have been included in the Guidelines. In dilated cardiomyopathy, due to the rarity of sudden cardiac death in pediatric age, low ejection fraction criteria were demoted to class II. In long QT syndrome, new criteria included severely prolonged QTc with different limits according to genotype, and some specific mutations. In arrhythmogenic cardiomyopathy, hemodynamically tolerated ventricular tachycardia and arrhythmic syncope were downgraded to class II recommendation. In conclusion, these new Guidelines aim to assess all aspects of cardiac implantable electronic devices and improve treatment strategies.