Uncovering possible silent acquired long QT syndrome using exercise stress testing in long-term pediatric acute lymphoblastic leukemia survivors.

An example of chemotherapy-induced cardiotoxicity in cancer survivors is acquired long QT syndrome (aLQTS), which may cause serious yet preventable life-threatening consequences. Our objective was to identify and characterize childhood acute lymphoblastic leukemia (ALL) survivors with possible aLQTS using maximal exercise testing. In this cross-sectional study with exploratory analysis, a total of 250 childhood ALL survivors were evaluated for abnormal QT interval prolongation using the McMaster cycle exercise test. A total of 198 survivors (102 males; 96 females), having reached their V ̇ O 2 $$ \dot{\mathrm{V}}{\mathrm{O}}_2 $$ peak (mean 32.1 ± 8.4 mL/kg/min; range 15.5-57.8 mL/kg/min), were included in our analyses. Two survivors were excluded for possible congenital LQTS. QT intervals were corrected for heart rate using the Bazett, Fridericia, and Rautaharju formulas at rest (supine, sitting, and standing positions), at the end of each stage of the CPET, and at 1, 3, and 5 minutes into the recovery period. The corrected QT (QTc) of borderline (n = 37) and long QT survivors (n = 20) was significantly longer than normal survivors (n = 141) at rest, exercise, and recovery. Out of 57 survivors presenting an abnormal QTc prolongation, 40 survivors (70%) showed no QT interval anomalies at rest but developed various anomalies during exercise. No significant differences were found between the groups for any of the measured clinical characteristics or cardiac parameters. The standardization of exercise testing in the regular follow-up of oncology patients is necessary for appropriate cardiac prevention and surveillance to enhance the health and quality of life of the ever-increasing number of cancer survivors.

Role of new generation implantable loop recorders in managing undiagnosed pediatric cardiac symptoms.

Pediatric cardiac symptoms such as palpitations, syncope, or seizure-like episodes pose diagnostic challenges for general pediatricians. These symptoms, though often benign, may reveal underlying arrhythmias or inherited cardiac conditions (ICCs), affecting the quality of life and limiting activity participation. The purpose of this study is to determine the effectiveness and safety of implantable loop recorders (ILRs) in diagnosing and managing arrhythmias in pediatric patients. A retrospective cohort study conducted over an 8-year period from January 2016 to December 2023 in a single pediatric cardiology center. A cohort of 155 pediatric patients (median age 11.4 years) who underwent ILR implantation were selected based on symptoms such as palpitations, chest pain, or syncope, and those with previously recorded arrhythmias or high-risk ICCs. The primary outcomes were the diagnostic yield of ILRs for arrhythmias and subsequent changes in patient management. Diagnostic yield was defined as the detection of relevant arrhythmias, such as pauses of 3 s or longer, high-degree AV block, sinus node dysfunction, supraventricular tachycardia, ventricular tachycardia, or inappropriate sinus tachycardia. The median follow-up period was 2.3 years (845 days). Diagnostic arrhythmias were recorded in 60% of patients with symptom-activated transmissions and 80% of device-activated transmissions. Sinus pauses (37.5%) and VT (30%) were the most common arrhythmias detected. In patients with syncope (n = 76), 30% had relevant arrhythmias. In the palpitations group (n = 20), 35% had relevant arrhythmias. Approximately 80% of patients with ILR-diagnosed arrhythmias underwent targeted management, including medication changes and additional procedures. No significant complications were observed; minor complications occurred in 2.5% of patients.Conclusions: New generation ILRs are effective and safe for diagnosing and managing pediatric arrhythmias, providing significant reassurance to patients and families. Further studies are needed to evaluate the impact of ILRs on quality of life and sports participation in high-risk young patients.

Outcome monitoring and risk stratification after cardiac procedure in neonates, infants, children and young adults born with congenital heart disease: protocol for a multicentre prospective cohort study (Children OMACp).

INTRODUCTION: Congenital heart disease (CHD) represents the most common birth defect, affecting from 0.4% to 1.2% of children born in developed countries. The survival of these patients has increased significantly, but CHD remains one of the major causes of neonatal and childhood death. The aetiology of CHD is complex, with some evidence of both genetic and environmental causes. However, there is still lack of knowledge regarding modifiable risk factors and molecular and genetic mechanisms underlying the development of CHD. This study aims to develop a prospective cohort of patients undergoing cardiac procedures that will bring together routinely collected clinical data and biological samples from patients and their biological mothers, in order to investigate risk factors and predictors of postoperative-outcomes, as well as better understanding the effect of the surgical intervention on the early and long-term outcomes. METHODS AND ANALYSIS: Children OMACp (OMACp, outcome monitoring after cardiac procedure in congenital heart disease) is a multicentre, prospective cohort study recruiting children with CHD undergoing a cardiac procedure. The study aims to recruit 3000 participants over 5 years (2019-2024) across multiple UK sites. Routine clinical data will be collected, as well as participant questionnaires collecting sociodemographic, NHS resource use and quality of life data. Biological samples (blood, urine and surgical waste tissue from patients, and blood and urine samples from biological mothers) will be collected where consent has been obtained. Follow-up outcome and questionnaire data will be collected for 5 years. ETHICS AND DISSEMINATION: The study was approved by the London-Brent Research Ethics Committee on 30 July 2019 (19/SW/0113). Participants (or their parent/guardian if under 16 years of age) must provide informed consent prior to being recruited into the study. Mothers who wish to take part must also provide informed consent prior to being recruited. The study is sponsored by University Hospitals Bristol and Weston Foundation Trust and is managed by the University of Bristol. Children OMACp is adopted onto the National Institute for Health Research Clinical Research Network portfolio. Findings will be disseminated through peer-reviewed publications, presentation at conference, meetings and through patient organisations and newsletters. TRIAL REGISTRATION NUMBER: ISRCTN17650644.

Indications and utility of cardiac genetic testing in athletes.

Sports Cardiology practice commonly involves the evaluation of athletes for genetically determined cardiac conditions that may predispose to malignant arrhythmias, heart failure, and sudden cardiac death. High-level exercise can lead to electrical and structural cardiac remodelling which mimics inherited cardiac conditions (ICCs). Differentiation between 'athlete's heart' and pathology can be challenging and often requires the whole armamentarium of available investigations. Genetic studies over the last 30 years have identified many of the genetic variants that underpin ICCs and technological advances have transformed genetic testing to a more readily available and affordable clinical tool which may aid diagnosis, management, and prognosis. The role of genetic testing in the evaluation and management of athletes with suspected cardiac conditions is often unclear beyond the context of specialist cardio-genetics centres. This document is aimed at physicians, nurses, and allied health professionals involved in the athlete's care. With the expanding role and availability of genetic testing in mind, this document was created to address the needs of the broader sports cardiology community, most of whom work outside specialized cardio-genetics centres, when faced with the evaluation and management of athletes with suspected ICC. The first part of the document provides an overview of basic terminology and principles and offers guidance on the appropriate use of genetic testing in the assessment of such athletes. It outlines key considerations when contemplating genetic testing, highlighting the potential benefits and pitfalls, and offers a roadmap to genetic testing. The second part of the document presents common clinical scenarios in Sports Cardiology practice, outlining the diagnostic, prognostic, and therapeutic implications of genetic testing, including impact on exercise recommendations. The scope of this document does not extend to a comprehensive description of the genetic basis, investigation, or management of ICCs.