Physical Activity and Functional Capacity in Patients With Congenital Long QT Syndrome

Patients with congenital long QT syndrome (LQTS) have traditionally been discouraged from physical activity and competitive sports, although the rate of exercise-related arrhythmic events is considered low. In recent years, international guidelines have become less restrictive and now support shared decision-making between physicians, patients and families to promote safe physical activity. Excessive restriction, especially in young people, may negatively affect mental health, quality of life and overall cardiovascular risk. However, little is known about the physical activity level and physical fitness of patients with LQTS in clinical practice. This observational study will describe the baseline functional capacity, physical activity level and quality of life of adults with congenital LQTS followed at the Arrhythmia Outpatient Clinic of the Heart Institute (InCor), São Paulo, Brazil, and compare them with patients with arrhythmias and a structurally normal heart. Participants will answer questionnaires on physical activity, quality of life and barriers to exercise, and will undergo cardiopulmonary exercise testing and 24-hour Holter monitoring. This is the first step of the Channelopathies Movement and Exercise Study (CANMOVE).

Inclusion Criteria: * Age 18 years or older * Confirmed diagnosis of congenital long QT syndrome, followed at the Arrhythmia Outpatient Clinic of the Heart Institute (InCor) * Signed informed consent Exclusion Criteria: * Acquired long QT syndrome * No diagnostic confirmation by clinical and/or genetic criteria, without the possibility of genetic testing as part of routine care * Corrected QT interval (QTc) persistently above 500 ms * Any implantable cardioverter-defibrillator (ICD) therapy or unexplained syncope in the previous 6 months * Bedridden patients or patients with walking difficulties * Eastern Cooperative Oncology Group (ECOG) performance status of 2 or higher * Non-adherence to drug treatment * Advanced-stage disease with estimated survival of less than 1 year * Advanced cognitive impairment or inability to answer the questionnaires