Predictors of Heart Rate Variability: A Systematic Review

Introduction: The heart has the ability to maintain cardiac output in accordance with the body’s momentarily changing demands by adjusting its rate of contractions and this ability is termed Heart Rate Variability (HRV), which is manifested as a fluctuation of R-R interval in milliseconds on an Electrocardiography (ECG). Maintenance of good HRV levels is significant for the patient population since they influence the prognosis and quality of life. Aim: To identify the predictors of HRV. Materials and Methods: The present study was a systematic and literature review which was based on Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) guidelines 2020. Randomised Controlled Trials (RCTs) published in English from 2014 to 2021 were identified from Cochrane Library, Science Direct, PubMed, and Google Scholar databases. The keywords with Boolean operators were used as “influencing factors or determinants or predictors and HRV.” The quality assessments of the studies were performed with Cochrane risk-of-bias assessment tool. Narrative syntheses upon the selected studies were done. Results: The significant findings from the nine selected RCTs were summarised. Physical exercise, breathing exercise, diet, music, and mind-body interventions such as yoga and meditation were identified as the factors enhancing HRV or predictors of HRV. Conclusion: The findings of this systematic review strive to facilitate healthcare providers to devise the strategies to support the risk group of low HRV by the implementation of enhancing factors of HRV to achieve a better outcome.