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

Abstract

Background: Evaluation of sympathetic baroreflex (sBR) function in humans requires intra-neural recording of muscle sympathetic nerve activity (MSNA) by microneurography.

Aims: We 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 & results: In nine healthy subjects (5M; 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.

Conclusions: SVR-based threshold-analysis is feasible in healthy young subjects and provides a promising alternative to the traditional MSNA-based approach.

Keywords: Microneurography; Muscle sympathetic nerve activity (MSNA); Sympathetic baroreflex; Systemic vascular resistance; Threshold-analysis.