ABC | Volume 110, Nº1, January 2018

Original Article Liporaci et al Effects of tilt test in healthy subjects Arq Bras Cardiol. 2018; 110(1):74-83 0.7 0.6 0.5 0.4 0.3 0.2 1 2 3 Time TD Figure 4 – Total displacement variation during the pre-Valsalva maneuver (VM) (1), VM (2) and post-VM (3) periods. Significant values between VM and pre-VM; p < 0.05. 0.07 0.06 0.05 0.04 0.03 0.02 VMedt 1 2 3 Time Figure 5 – Total mean velocity variation during the pre-Valsalva maneuver (VM) (1), VM (2) and post-VM (3) periods. : Significant values between VM and pre-VM; p < 0.05; : significant values between post-VM and VM; p < 0.05. increased sympathetic activity and peripheral resistance. Loss of consciousness in CNS patients may be a response to impaired venous return. 17 Despite the assumption that the body may be represented by an inverted pendulum during standing, as proposed in kinematic, kinetic and EMG studies, 18,19 slight displacement of joints that maintain the standing posture, such as the ankle and the hip, have an important role in orthostatism that cannot be ignored. 20-22 Aware of the role of the musculoskeletal system as the venous return protagonist by means of muscle contraction below the heart, we decided to register the activity of some muscles involved in the ankle strategy for maintenance of standing position – the AT and the gastrocnemius – as well as muscles involved in the maintenance of upper hemibody posture – the RA muscle and the ES – and compare it between the two tests. For seven of the eight muscles studied, there was a progression of changes, especially until 78