linear heart rate variability measures in sickle cell disease compared to the healthy control subjects: a systematic review and mete-analysis study

Introduction: heart rate variability represents the performance of the cardiac autonomic nervous system (ans) and is defined as the fluctuation of beat-to-beat between two successive r-waves (rr intervals). accordingly, addressing the actions of the ans in sickle cell disease helps in identifying the possible risk factors of sudden death. the clinical staging of the disease improves the diagnosis and the quality of the treatments. methods: this systematic review analyzed the data of the basal autonomic reactions in sickle cell anemia (sca) and sickle cell trait (sct) patients compared to healthy people. in this study, 441 articles were retrieved from pubmed, proquest, scopus, embase, and web of science databases. some of them were removed based on the inclusion and exclusion criteria, and finally, seven articles remained for analysis. results: the data analysis of the included studies demonstrated that the vagal modulation at the basal condition decreased in sca or sct patients compared to the control group. conclusion: the sympathovagal balance was altered in sca or sct patients, and an increasing trend was observed in sympathetic nerve activities.