Concerning all etiological factors for the increasing factors of Chronic Cerebral Ischemia (CCI) fits into the concept of the creation of a stable pathological system in the central nervous system (CNS). Aim. The evaluation of the increasing factors for the formation of a pathological system of the brain, peculiarities of cerebro-cardial interactions with the help of parameters of quantitative electroencephalography and heart rate variability in patients with CNS of different genesis. Materials and methods. At aged from 40 to 68 were comprehensively examined 88 people in dynamics in the period from 2016 to 2019. The registration of brain biopotentials was recorded using Tredex Expert computer-based electroencephalograph. For the analysis of EEG, the amplitude-time representation of an unsteady signal and its result of continuous wavelet transform were used. In the dynamics of therapy, an analysis of quantitative EEG (qEEG), heart rate variability (HRV) (Utas UM 200) was proceed. Results and discussion. Using the method of quantitative EEG with a wavelet conversion of a stationary EEG signal , the formation and destruction of stable pathological systems of the brain in patients with stroke, transient cerebral ischemia (TCI), MCI grade 2 were studied. In patients with MCI grade 2, in contrast to the “healthy brain”, the role of the “central contour” of regulation of heart rate variability shifts from the vegetative centers of the medulla oblongata to the region of diencephalic formations; in the thalamus area; into the hypothalamic zone. In patients with stroke, the role of the "central contour" is shifted to the region of limbic-hippocampal formations, the diencephalic zone, the area of the thalamus and ascending thalamocortical pathways. In patients with TCI, the role of the “central contour” shifts to the cortical region (signs of cortical irritation), diencephalic zone, thalamus and descending corticothalamic pathways. Conclusions. The positive effect of therapy when acting on the formed pathological system should be considered the appearance of an EEG on the wavelet graph in parallel with the dominant frequency of the subdominant frequency in the alpha range, the movement of the “central contour” of regulation of heart rate variability in the region of the vegetative centers of the medulla oblongata.