New adrenergic baroreflex evaluation in Valsalva maneuver

Abstract

Background: Valsalva maneuver (VM) is a simple and non-invasive technique extensively utilized clinically to detect dysautonomia. VM provides detailed information of baroreflex sensitivity (BRS) which is an important cardiovascular and autonomic marker. However, the current approach for calculating its adrenergic component (BRSa1) is moderately reliable and fails to evaluate atypical VM patterns. Methods: We analyzed typical and atypical VM patterns of 89 young, healthy individuals (30 ±13 years) with the aim of improving BRSa evaluation. Objectives: 1) To determine a new BRSa calculation (BRSa2) applicable to different VM patterns; 2) correlate BRSa2 to BRSa1; 3) compare the internal consistency (ICC) between BRSa1 and BRSa2. Results: The BRSa2 calculation is a complex hemodynamic and time assessment equivalent to the slope in vagal BRS. In contrast to BRSa1, BRSa2 operates with hemodynamic indices easily detectable in any VM pattern. In atypical VM patterns, BRSa2 correlated with BRSa1: “flat-top responses” (r = 0.774, p < 0.01); rapid hemodynamic recovery (r = 0.461, p < 0.05). Most importantly, BRSa2 was more reliable than BRSa1 (ICC= 0.759 versus 0.469). Conclusion: BRSa2 is more reliable and allows atypical responses to VM to be analyzed, which clinically, could help differentiate natural physiological variances and mild adrenergic dysfunction.