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

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.