Non-invasive approach for the assessment of sympathetic baroreflex function: A feasibility study

BackgroundEvaluation of sympathetic baroreflex (sBR) function in humans requires intra-neural recording of muscle sympathetic nerve activity (MSNA) by microneurography.AimsWe proposed noninvasive approach for the evaluation of sBR function by applying the threshold-analysis (traditionally, based on MSNA) to systemic vascular resistance (SVR) measurement by photoplethysmography.Methods & resultsIn nine healthy subjects (5 M; age: 25 ± 5y), the threshold-analysis was calculated twice: using MSNA and SVR. Both methods yield comparable results in men (T50(burst-vs.-svr): CV = 8.8%, r > 0.9; Slope(burst-svr): CV = 30.1%; r > 0.9), but not in women.ConclusionsSVR-based threshold-analysis is feasible in healthy young subjects and provides a promising alternative to the traditional MSNA-based approach.