Heart rate increase results in case of positional venous entrapment

INTRODUCTION: Tachycardia has previously been reported as a possible sign of neurovascular entrapment during upper-limb abduction and assumed to result from compression of the adrenergic nerve. However, this increase in heart rate could also be caused by a vascular factor, such as venous entrapment. The aim of this study was to determine whether heart rate increases specifically in the case of venous entrapment during upper-limb dynamic mobilization tasks. METHODS: One hundred and sixteen patients were asked to perform a provocative manoeuvre consisting of consecutive upper limb mobilizations by raising their arms to the "surrender" position (Su, 90° abduction) and then keeping their arms raised in front of the body ("prayer" position, Pra) prior to returning to the initial position ("End"). During this manoeuvre, simultaneous venous (V-PPG) and arterial (A-PPG) photoplethysmography (PPG) recordings were obtained. Participants were categorized by PPG recording analysis as having bilateral venous compression only (V-group) or having no vascular compression (C-group). All other responses (n = 75) were excluded. Heart rate responses in V-group and C-group were compared across arm positions using a linear mixed model. RESULTS: V-group (n = 17) showed a significantly higher heart rate during the 'Su' phase compared to the 'Rest' phase (+6.9 bpm, p < 0.001) and compared to the 24 patients of the C-group (+4.9 bpm, p = 0.02). CONCLUSION: This study suggests that the cardiovascular response to dynamic provocative manoeuvres is found specifically in the presence of positional venous upper-limb entrapment and likely results from decreased cardiac pre-charge rather than from adrenergic nerve excitation.