Sample entropy analysis of hemodynamic parameters in elderly with orthostatic intolerance

This study focuses on examining the hemodynamic profile in older people with symptoms of orthostatic intolerance (OI) undergoing an active stand and to investigate if their dynamic cardiovascular profile during six-minute walk distance would be different to those of controls. The database included a total of 65 participants, aged over 70 years of age (70.11±5.85), of whom 65% were females. The participants underwent a supine to stand orthostatic test with non-invasive beat to beat systolic (SBP) and diastolic blood pressure (DBP) and inter-beat interval (R-R) monitoring. Sample Entropy (SampEn) method was calculated at each phase. R-R SampEn values showed statistically significant differences during Phase 2 and Phase 4 between symptomatic and asymptomatic OI participants. This study empathizes the importance of entropy analysis to extract information of cardiovascular signals. SampEn based measures might provide useful indicators of pathological changes in cardiac activity and be suitable for the early detection of autonomic cardiovascular dysfunction.