Comparing the Effect of Moderate-Intensity Versus High-Intensity Interval Training Exercise on Global Longitudinal Strain (GLS) in Cardiovascular Patients: Systematic Review and Meta-Analysis.

Left ventricular global longitudinal strain (LVGLS) is a highly sensitive echocardiographic biomarker that detects signs of myocardial dysfunction. It has been proven that exercise-based cardiac rehabilitation (CR) improves LV-GLS but whether high-intensity interval training (HIIT) is more efficient than moderate-intensity interval training (MIIT) to improve LV-GLS as cardiac deformation index in cardiovascular patients is debatable. In the current systematic review and meta-analysis, different digital databases including PubMed, Scopus, Web of Science (ISI), and Google Scholar were searched systematically with no time restriction to answer the abovementioned question. Studies were included that reported GLS as the outcome in CVD subjects before and after enrolling in HIIT and/or MITT. A random effects model was used for meta-analysis. Eleven sets of results from nine articles-two of which had two sets of results-were included. The result of the sensitivity test to check the publication bias was not significant either for MIIT (p=0.211) or for HIIT (p=0.238). Our findings showed that GLS was improved significantly after both MIIT (-1.72. [-2.68, -0.77]) and HIIT (-1.86 [-3.01, -0.71]) in CVD patients; however, the effect of HIIT was greater than MIIT. Subgroup analysis results showed that baseline disease and duration of exercises do not influence the effect of training on GLS. More studies are needed to confirm the conclusion.