An observational study in Long QT Syndrome, Catecholaminergic Polymorphic Ventricular Tachycardia Type 1 and Catecholaminergic Polymorphic Ventricular Tachycardia Type 2, sponsored by Royal Brompton & Harefield NHS Foundation Trust. Completed at 2 sites in United Kingdom. Open to participants aged 6 Years to 16 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-09-01.
Sponsored by Royal Brompton & Harefield NHS Foundation Trust · Observational
The goal of this observational study is to evaluate exercise testing and daily physical activity in children and adolescents who are diagnosed with an inherited arrhythmia.
The main question it aims to answer is: Does maximum heart rate during controlled exercise tolerance testing accurately reflect maximum heart rate and peak exercise levels during free living daily physical activity in children and adolescents diagnosed with an inherited arrhythmia?
Participants will:
Exercise tolerance testing (ETT) using an exercise treadmill is a tool used to assess children's physical response to stress, which is thought to accurately reflect normal physiology during normal daily activities and can be used to:
The maximum heart rate achieved during ETT is used to estimate the effect of daily medications and to guide exercise prescription.
Originally designed to assess adult heart disease patients, ETTs were not intended for use in children. To accommodate the needs of children, shorter ETT protocols have been developed which increase the speed and/or incline of the treadmill quickly.
Despite this, many children rarely complete the full ETT protocol as they grow tired or develop other symptoms, which leads to them stopping exercise early, resulting in variable lengths of testing.
Children naturally increase exercise effort during day-to-day free-living physical activity (PA). Free-living PA is therefore thought to show a more accurate representation of the maximum heart rate (HR) children can achieve. Presently there is no strong evidence base to determine what children with an Inherited Arrhythmia (IA) (a genetically inherited heart condition which causes abnormalities in the heart rhythm) are doing in terms of daily free-living PA and exercise. The current recommendations used to prescribe exercise for this patient group are based on expert opinion and are not child specific. The study I propose supports the development of a greater evidence base to guide future exercise prescription and better tailored medications.
The study aims to:
To achieve these aims, the study will recruit children (aged 6-16 years) diagnosed with an IA and who are able to run on an exercise treadmill, plus a healthy control group (unaffected siblings, or children undergoing screening).
A clinical ETT will be performed as part of routine care. Each participant will be given a wearable PA monitoring device to monitor free-living PA over two-weeks. The device will record parameters such as electrocardiogram, HR, and step count. PA will also be recorded digitally to capture type and length of activity they engage in, and estimated intensity.
At the end of the two-weeks, participants will complete a questionnaire about their PA which will be compared with the data obtained during the monitoring period. Parents will be invited to support younger children with questionnaire and digital recording completion.
A study lay advisory group will be established including children and their parents affected by an IA. They will advise on study design and development of all patient-facing information throughout the study.
The results of the study will be discussed with lay advisory groups who will advise on the best ways to share results with the wider public but will include publication in high quality Open Access journals and dissemination at relevant national and international conferences. Invitations will also be provided to the voluntary support groups involved in the early planning phases to publish the results on their websites
95 studies on the registry are indexed under Long QT Syndrome; 20 are open to participants now.
This study's enrollment of 55 is below the median of 150 across 48 observational studies indexed under Long QT Syndrome.
Browse Long QT Syndrome studies →Royal Brompton & Harefield NHS Foundation Trust is the lead sponsor of 137 studies on the registry; 18 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Affected cohort: 60 children aged 6-16 years, diagnosed with inherited arrhythmias (IAS)
Unaffected cohort: 50 healthy children aged 6-16 years (siblings of affected children and those undergoing screening for inherited arrhythmias)
Affected cohort
Healthy cohort
Exclusion Criteria:
Children diagnosed with Long QT Syndrome and Catecholaminergic Polymorphic Ventricular Tachycardia
Diagnostic Test: Exercise tolerance test · Other: Physical activity & heart rate monitoring
Healthy children (siblings of affected or those undergoing screening)
Diagnostic Test: Exercise tolerance test · Other: Physical activity & heart rate monitoring
Clinical routine exercise tolerance test using an exercise treadmill, according to the arrhythmia protocol (15 minute protocol utilising increasing speed and incline with a 6 minute recovery)
Physical activity monitoring over two weeks using Actiheart and Pro-Diary monitors to record heart rate, heart rhythm, activities engaged in and estimated intensity of activities.
Correlation of maximum heart rate during clinical exercise tolerance test and daily physical activity
Assess the correlation between maximum heart rate (HRmax) obtained during controlled exercise tolerance test (ETT) and wearable heart rate devices during daily free-living (FL) physical activity (PA) and exercise.
Time frame: Baseline assessment (week one of study assessments)
Physical activity questionnaire
Investigate actual versus reported PA children engage in using a questionnaire to record accuracy of child/parent recall of the type and intensity of PA.
Time frame: End of two-week physical activity monitoring (week two of study assessments)
Heart rate assessment during exercise tolerance testing
Assess differences in HRmax relative to age of children completing three ETT protocols i. Bruce/modified Bruce with accelerated sprint - Evelina London Children's Hospital (ELCH) ii. Arrhythmia high intensity (HIT) - Royal Brompton Hospital (RBH) iii. Arrhythmia - Great Ormond Street Hospital (GOSH)
Time frame: Baseline assessment (week one of study assessment)
Comparison of exercise tolerance testing protocols
To compare protocols between the centres to determine if one protocol correlates more closely with HRmax (protocol completion or no further rise in HR despite increasing workload) achieved during FL PA.
Time frame: Immediately after the intervention
Documents are hosted by the registry — open the source record to download them.
Plan to share: No — To be completed
This study is completed, as verified in Aug 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Royal Brompton & Harefield NHS Foundation Trust