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 Pre-VM Post-VM VM 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2 0.22 lTA rTA lRA rRA lMG rMG lES rES a a b a b a b a b a b a b A c A c A c A c A c A C B B B C B C B C B C A % maximum effort Figure 6 – Percentage of maximum effort in relation to the electromyographic activity recorded during the test divided into three stages: pre-Valsalva maneuver (VM), during the VM and post-VM during the Active Standing Test. A, B, C: significant difference with their corresponding muscles (a,b,c): p < 0.05. Pre-VM Post-VM VM 0 0.02 0.04 0.06 0.08 0.1 a a a b a b a b a b a b b A A A c A c A c A c A c C C B B B B C B C B C % maximum effort lTA rTA lRA rRA lMG rMG lES rES Figure 7 – Percentage of maximum effort in relation to the electromyographic activity recorded during the test divided into three stages: pre-Valsalva maneuver (VM), during the VM and post-VM during the Head-Up Tilt Test Test. A, B, C: significant difference with their corresponding muscles (a,b,c): p < 0.05. the end of the VMs. However, for rRA during the AS and for rMG during HUT had no statistical relevance in the changes observed during the VMs as compared with the pre-VM during orthostatism. If we compare the electrical activity between AS and HUT, we find a higher EMG activity during AS than HUT, except for the rES and lES, whose activity was higher in the HUT than AS. These data corroborate our hypothesis that the role of muscles would be different in each test. AS allows the use of muscle strategies for postural maintenance by contraction of the muscles, as the patient feels the necessity to correct eventual body sways that may make him fall. On the other hand, during the HUT, such strategies are compromised and the patient can bend forwards only, since the patient is kept 79