PSI - Issue 40

V. Mironov et al. / Procedia Structural Integrity 40 (2022) 296–306

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V. Mironov at al. / Structural Integrity Procedia 00 (2022) 000 – 000

and collected in a special file in the computer operative memory in the archive with the resolution till 1 millisecond. HRV-records may be displayed on the monitor with synchronous ECG-record with the conclusion of a specialist in RCG. RCG is a graphic image of intrasystole pauses between heart contractions in the form of the vertical rectilinear pieces equivalent in size to the duration of RR intervals. It is consistently built on graphics from the beginning on the abscissa axis and with continuation parallel to the ordinate axis (Figs. 1 – 5). The stages of anesthesiology and the surgical operation were registered during all CABGS with time marks, with the indications of entered preparations and surgical manipulations. It presents an opportunity to observe all the changes of RCG in comparison to initial RCG HRV patterns during intervention. Four editor computer programs for correction of RCG may be used for the removing of artifacts in every 300-interval fragments before correcting HRV-analyses. Artifacts were caused by the influence of the electric knife during operation, direct surgical manipulations on the heart tissues, noises and movements of the pt at the first RCG – studying before operation. Episodes of the cardiac arrest under the influence of the introduction of drugs were registered during the preparation of the passage of heart contractions to artificial circulation (pump), during restoration of the heart activity after the end of cardiac shunting. During CABGS, the real work was provided to the analysis of results of HRV monitoring and dynamics of its changes. In figure 3, RCG shows the reduction of HRV waves with the expressive HRV stabilization. The spectral changes reflected the transition of the heart rhythm regulation to the humoral-metabolic level in the form of an increase in a percentage share of a very low frequency (VLF%). The spectrograms of the shares of HRV waves have shown the prevalence of the humoral-metabolic influences (black part of the spectrogram – VLF%). The sympathetic (LF%) and parasympathetic (HF%) autonomic regulations in SN were almost absent. On spectrograms, there are pathologically changed spectral shares of the influence of the regulation factors in SN with autonomic oppression and significant increase in the humoral-metabolic influence, slow and inadequate. The regulative humoral prevalence and loss of the autonomic control are dangerous, namely it may result in the appearance of cardiac arrhythmias.

Fig. 3. RCG, spectrogram, and average HRV indices after the premedication and intubation narcosis during CABGS in a pt with angina pectoris of FC 4.

The clip installation on the aorta and the introduction of the cardioplegic solutions caused a stop of blood entering into aorta from the left heart ventricle. Simultaneously, blood entered from the apparatus of artificial circulation (Fig. 4). The surgical manipulations with heart ventricles caused cardioarrhythmias in the form of a number of polyfocal ventricular extrasystoles (VE) and replaceable rhythms, episodes of ventricular tachycardia (VT), and asystole (AS). The change intervals correspond to a part of ECG.