Search

Current exercise recommendations make it difficult for long QT syndrome (LQTS) patients to adopt a physically active and/or athletic lifestyle. The purpose of this review is to summarize the current evidence, identify knowledge gaps, and discuss research perspectives in the field of exercise and LQTS. The first aim is to document the influence of exercise training, exercise stress, and postural change interventions on ventricular repolarization in LQTS patients, while the second aim is to describe electrophysiological measurements used to study the above. Studies examining the effects of exercise on congenital or acquired LQTS in human subjects of all ages were included. Systematic searches were performed on 1 October 2021, through PubMed (NLM), Ovid Medline, Ovid All EBM Reviews, Ovid Embase, and ISI Web of Science, and limited to articles written in English or French. A total of 1986 LQTS patients and 2560 controls were included in the 49 studies. Studies were mainly case–control studies (n = 41) and examined exercise stress and/or postural change interventions (n = 48). One study used a 3-month exercise training program. Results suggest that LQTS patients have subtype-specific repolarization responses to sympathetic stress. Measurement methods and quality were found to be very heterogeneous, which makes inter-study comparisons difficult. In the absence of randomized controlled trials, the current recommendations may have long-term risks for LQTS patients who are discouraged from performing physical activity, rendering its associated health benefits out of range. Future research should focus on discovering the most appropriate levels of exercise training that promote ventricular repolarization normalization in LQTS.

Exercise-induced ischemic preconditioning (IPC) can be assessed with the second exercise stress test during sequential testing. Exercise-induced IPC is defined as the time to 1 mm ST segment depression (STD), the rate-pressure product (RPP) at 1 mm STD, the maximal ST depression and the rate-pressure product at peak exercise. The purpose of this meta-analysis is to validate the parameters used to assess exercise-induced IPC in the scientific community. A literature search was performed using electronic database. The main key words were limited to human studies, which were (a) ischemic preconditioning, (b) warm-up phenomenon, and (c) exercise. Meta-analyses were performed on the study-specific mean difference between the clinical measures obtained in the two consecutive stress tests (second minus first test score). Random effect models were fitted with inverse variance weighting to provide greater weight to studies with larger sample size and more precise estimates. The search resulted in 309 articles of which 34 were included after revision (1053 patients). Results are: (a) time to 1 mm ST segment depression increased by 91 s (95% confidence interval (CI): 75-108), p < 0.001; (b) peak ST depression decreased by -0.38 mm (95% CI: -0.66 to -0.10), p < 0.01; and (c) rate-pressure product at 1 mm STD increased by 1.80 × 10(3)mmHg (95% CI: 1.0-2.0), p < 0.001. This is the first meta-analysis to set clinical parameters to assess the benefit of exercise-induced ischemic preconditioning in sequential stress testing. The results of this first meta-analysis on the sequential stress test confirm what is presented in the literature by independent studies on exercise-induced ischemic preconditioning. From now on, the results could be used in further research to set standardized parameters to assess the phenomenon.