Long QT syndrome and current exercise recommendations: do we speak an infinite deal of… nothing?

To begin, we would like to thank Drs Ritt, Milani, and Stein for their recent editorial¹ and their interest in our scoping review on the influence of exercise and postural changes on ventricular repolarization in the long QT syndrome (LQTS).² Their editorial has brought complementary information that is crucial to understanding the pathophysiology of LQTS, as well as the reality of diagnosed patients and their families. They also shed light on the scope of the current physical activity and sports recommendations for this population.

Does current evidence-based medicine fully support the exercise recommendations for long QT syndrome?

Although scientific research and published papers should be accessible to everyone, it is important to acknowledge that some findings may be subject to interpretation. Thus, the interpretation that one can make of the current physical activity and sports recommendations for LQTS patients may be that physical inactivity is better than physical activity.³ While recommendations are at the heart of good practice, we should be promptly reminded that there are no randomized controlled trials in the field of exercise and LQTS to support the current recommendations.² As reported in our scoping review, only case control studies, retrospective cohort studies, and cross-sectional studies have been conducted in the field of exercise and LQTS.² Therefore, it is difficult to fully weigh in on these recommendations, which incites us to raise the following question: ‘Do the current recommendations harm more than they protect the majority of patients with LQTS?’ A longitudinal randomized clinical trial should provide the answer.

Lack of physical activity is harmful to patients’ health

According to Werner and colleagues (2013), only 19% of congenital heart disease patients receive formal physical activity advice from their health care professionals. In fact, they are often encouraged towards a sedentary lifestyle due to overprotection and a lack of specific exercise guidelines, including modality, frequency, intensity, time, and type.⁴ When recommendations that tend to exclude physical activity are given to these newly diagnosed, young patients who are at a critical point in their development, there can be various negative effects on physical and intellectual health, as well as current and future quality of life.⁵ Exercise in children should be geared towards spontaneous play, as it is recognized as a fundamental biological regulator of growth and development.^6,7 As nicely pointed out by Ritt, Milani, and Stein, there is also a risk of social and psychological harm when excluding exercise and sports from young patients’ lives.¹ Currently, patients with LQTS have the additional burden of a sedentary lifestyle along with its cohort of comorbidities. In other words, if inactive patients survive a sudden potentially fatal LQTS-related cardiac episode, they will probably suffer -or die- from an early heart disease or other chronic condition: a major lose–lose situation.

Physical activity: a physiological need at any age regardless of illness

For years now, we have accumulated unshakable evidence supporting the inverse relationship between regular physical activity and/or exercise and a myriad of chronic diseases, such as cardiovascular diseases, hypertension, stroke, osteoporosis, Type 2 diabetes, metabolic syndrome, obesity, cancer, depression, functional health, falls, and cognitive function.⁸ As stated by the American College of Sports Medicine, there is also strong evidence of a dose–response relationship between physical activity and risk of cardiovascular diseases and premature mortality proven by several large-scale epidemiology studies.⁸ Evidence-based medicine is as important for developing children, as the well-known European Youth Heart Study strongly supports the fact that physical activity levels should be higher than the current international guidelines of at least 1 h per day of moderate to vigorous intensity physical activity to prevent clustering of cardiovascular disease risk factors.⁹ Therefore, engaging in daily physical activity is needed to maintain adequate health and function for all individuals at all ages. Now, why should LQTS patients be excluded?

The next step for long QT syndrome patients: risk-benefit analysis of physical activity

The current studies and recommendations regarding LQTS patients and physical activity have done a very good job of putting forward the RISKS. Moreover, in addition to the lack of randomized controlled trials in this field, it is important to recognize that published studies are heterogeneous, thus limiting the scope of their findings. And so it is time for clinicians and researchers to emphasize the potential risk of not exercising, or the potential BENEFITS of exercise in LQTS. To reach this goal, we undoubtedly require randomized controlled trials including the different LQTS subtypes and various exercise modalities and parameters to address the many unanswered questions. As discussed by Ritt et al.,¹ a safe and individualized approach may be necessary to allow these patients to benefit from the protection of chronic exercise training, certainly regarding the potential pathologies and comorbidities of physical inactivity, but also possibly regarding the normalization of ventricular repolarization in and of itself.

We hope that our scoping review will help move the field of exercise and LQTS on to the next research steps. In fact, our research team is currently working on a systematic review and meta-analysis (PROSPERO #CRD42022311591) focusing on the effects of different exercise testing modalities on the QT interval response in LQTS. This work should bring new insight to clinicians and researchers to enhance the current exercise recommendations, as well as to safely guide LQTS patients in their daily physical activity.

Acknowledgements

We appreciate the assistance of Mary Ann Hoskin (language editor) for her review and edit of the article in the English language.

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