PSI - Issue 65

Mironov V.A. et al. / Procedia Structural Integrity 65 (2024) 147–151 Author name / Structural Integrity Procedia 00 (2024) 000–000

148

2

volume of intervention based on a preoperative assessment – Zulenski et al. (1997). Intraoperative neuromonitoring (IONM) is used, although it is known that the leading source of postoperative dysfunction of the recurrent nerve branch (RNB) is not transsection, but nonstructural functional injury – Hermann et al. (2004), Barczyński et al. (2009), Schneider et al. (2016). One of the high-resolution methods for assessing the risk of perioperative complications is the study of the vegetative regulation state of heart rhythm. Its use is justified by the possibility of the initial manifestations of diseases registering, complications arising from vegetative dysregulations specific to each disease – Malik et al. (1996), Sassi et al. (2015), Billman et al. (2015). There is a known study of the relationship between heart rate variability (HRV) and all–cause mortality in a cohort of 736 subjects (age 72 ± 6 years, 74 people died) during 4 years of follow-up using 5 measurements of the intersystolic intervals duration in the frequency domain and three measurements in the time domain (very low frequency power from 0.01 to 0.04 Hz, low–frequency – 0.04-0.15 Hz and high–frequency power – 0.01-0.4 Hz). In a step-by-step regression analysis with the inclusion of well-known risk factors, the low-frequency power (P <0.0001) of the heart rate with a decrease of 1 standard deviation was associated with a 1.7-fold increase in mortality from all causes (95% confidence interval 1.37-2.09). It was concluded that HRV provides independent prognostic information in addition to that provided by the assessment of traditional risk factors – Tsuji et al. (1994). It was the basis for conducting this study.

2. Purpose

The prediction of long-term outcomes of interventional interventions in patients with stable angina pectoris (SAP) depending on the features of autonomic regulation of heart.

3. Materials and methods

As a special research method, we used the analysis of HRV – Mironova and Mironov (1989), Mironov and Mironova (1994) using a hardware and software complex Mironov et al. (2002), with cutaneous registration of electrocardiosignal (ECS), subsequent amplification, interference filtering, analog-to-digital conversion and ECS- transmission in digital form to a personal computer (PC). The graphic construction of a rhythmocardiogram (RCG), its analysis and processing, registration of an electrocardiography (ECG), data storage in PC memory for the purpose of diagnosing disorders of peripheral autonomic regulation of the heart sinus rhythm based on temporal and wave HRV spectral analysis were carried out when using computer programs "Mikor" in the PC and software complex KAP-RK-01-"Mikor" – Mironov and Mironova (1995). 25-30 RCG records were statistically analyzed for 300 episodes of intersystolic intervals with high sensitivity of ECS, reflecting changes in RCG at the surgery stages. The comparison of the study results was carried out continuously using the program Stat.exe in the software KAP-RK 01-"Mikor". The study was conducted before, during, and after surgery for 39 patients with a confirmed NFTG diagnosis. These patients were subject to surgical treatment. Оf these, NFTG patients with a median age of 47 (28...64 years) and thyroid cancer (TC) patients with a median age of 47 (24...71 years). The following aspects were identified during continuous monitoring of the duration of intersystolic intervals during surgery: 1) signs of a systemic increase in the vagal effect on heart rate regulation in the form of significant increases in the amplitude of respiratory arrhythmia, including all values of RR-intervals before smoothing by Humming and Parsen windows (ARA); 2) an increase in the indicators values reflecting an increase in the influence of parasympathetic waves in absolute values (standard deviation σs) and in relative spectral parameters in the form of an increase in the spectral fraction of high-frequency waves (HF%) in the overall wave structure of the heart rate (Table 1). The table shows that the most responsive part of the wave spectrum in the general structure of the heart rate belongs to the high-frequency wave periodicity in the form of the highest values of the amplitude of respiratory arrhythmia (ARA), absolute (σs) and relative values (HF%) of rhythm variability. It indicates the greatest interest in parasympathetic influence on heart rate regulation, while all components – the sympathetic, parasympathetic and humoral-metabolic environment are oppressed during general anesthesia. 4. Results and discussion