Autonomic Reactivity in Young Persons with Arterial Hypotension

The analysis of autonomic reactivity is based on study of dynamics of indicators of cardiointervalography during orthostatic test in two positions. It was established that SI (stress index) 1in persons of control group equals 55 SU showing autonomic homeostasis. The increasing of SI up to 131,6 SU was defined after orthostatic test that is in the physiologic range, where correlation of SI1/SI2 equals 2,38 characterizing normal autonomic reactivity. Due to analysis of transitive period of orthostatic test it was defined that R-Rmin equals 0,64 sec and corresponds to 93,7 bpm and R-R max equals 0,95 sec and corresponds to 63,2 bpm. The reaction coefficient was studied and equaled 33% with following recovery of HR starting from the 4th min. It was established that SI1in persons with moderate hypotension equals 38,5 SU showing autonomic homeostasis. The increasing of SI up to 106,3 SU that is in 2,7 times more than in initial state was defined after orthostatic test, where correlation of SI1/SI2 equals 2,8 indicating some excess activation of the sympathetic division of the autonomic nervous system. Due to analysis of transitive period of orthostatic test it was defined that R-Rmin equals 0,68 sec and corresponds to 88 bpm and R-R max equals 1,04 sec and corresponds to 57 bpm. The reaction coefficient was studied and equaled 34% with following slow recovery of HR. It was established that SI1in persons with severe hypotension equals 24,5 SU showing autonomic homeostasis. The increasing of SI up to 80,4 SU that is in 3,2 times more than in initial state was defined after orthostatic test, where correlation of SI1/SI2 equals 3,2 indicating excess activation of the sympathetic division of the autonomic nervous system. Due to analysis of transitive period of orthostatic test it was defined that R-Rmin equals 0,67 sec and corresponds to 89,6 bpm and R-R max equals 1,06 sec and corresponds to 56,6 bpm. The reaction coefficient was studied and equaled 37% with following slow recovery of HR. In order to study autonomic reactivity the Stange-Hench tests have been used. The duration of Stange test in persons of control group is 50.8 and duration of Hench test is 23,5 sec in young women and 25,8 sec in young men, which corresponds to normal parameters, while the rate of CV Sreaction which characterizes sustainability of CVS to hypoxia and hypercapnia and reflects the general state of oxygen-transporting systems, equals 1.07 for young women and men, indicating adequate sensitivity of inspiratory neurons to hypoxia and hypercapnia, as well as anadequate response to their ritant factor of CVS and the unidirectional adaptation of myocardium in the seconditions. In persons with moderate hypotension maximal duration of breath holding equals 27.8 sec, which is characterized as unsatis factory sample, and the rate of CV Sreactionis 1.11. In Hench test sit was found that maximal duration of breath holding is 19.5 seconds, while the rate of CV Sreactionis 1.05. In persons with severe hypotension there sults of Stange tests prove that maximal duration of breath holding is 25.6 seconds, which is also characterized as unsatis factory response, where the rate of CVSreactionis 1.08. Also, Hench tests in this group found that maximal duration of breath holdingis 19.3 seconds, while the rate of reaction CVSequals 1.05. Thus, it becomes possible to make in direct conclusion about hypersensitivity of inspiratory neuron sand chemoreceptors of vessels to hypoxia and hypercapnia in persons with arterial hypotension that was confirmed by less maximal duration of breath holding and reduced adaptationof oxygen-transporting systems, and reduced stability of CVS to hypoxia, that was proved by excessive autonomic reactivity at lower maximal duration of breath holding.