This paper describes in detail a new method proposed by authors for quantitative estimation of the strength of synchronization between the low-frequency oscillations (with the main frequency of about 0.1 Hz) in the heart rate variability (HRV) and photoplethysmogram (PPG). Calculation of index value is followed by statistical significance control. The proposed method is applied for the analysis of 1056 pairs of HRV and PPG signals obtained from patients having different clinical status. Methodological recommendations are developed for method application in clinical studies.
Anton R. Kiselev, Anatoly S. Karavaev, Vladimir I. Gridnev, Mikhail D. Prokhorov, Vladimir I. Ponomarenko, Ekaterina I. Borovkova, Vladimir A. Shvartz, Yurii M. Ishbulatov, Olga M. Posnenkova, Boris P. Bezruchko Method of estimation of synchronization strength between low-frequency oscillations in heart rate variability and photoplethysmographic waveform variability // Russian Open Medical Journal, Vol. 5, Issue 1, 2016, pp. 0-0

The aim of the article: the peculiarities of the modern methods of treatment efficiency objective assessment in considerable contingent of patients with intraperitoneal bleeding of a genital origin are investigated. Material et metods: The original data of intra- and postoperative medical interventions efficiency are given and analyzed in 78 patients who were operated laparoscopically owing to intraperitoneal bleedings up to 500 ml of blood. Results. Circulating blood volume in these patients was restituted by blood Autohaemoreinfusion together with donors' blood and blood-substituting compounds injection. Red blood cells and hemoglobin content together with heart rate variability indexes were taken as the markers of the patients' organism functional condition and rehabilitation efficacy estimation. One month after miniinvazive treatment in women with acute intraperitoneal blood loss above 500 ml one could see certain sympathetic activation with reciprocal parasympathetic activity suppression together with pertinent activation degree value normalization. Conclusions. The conclusion was made that HRV data analysis allows to make an objective estimation of women with acute genital intraperitoneal bleeding (above 500 ml) treatment efficacy. The last is very important in the prognostic aspect because there are few objective methods of afteroperational state analysis in patients with bleeding of different origin.
Nazarenko O.Ya., Timofeyeva S.V. The contemporary methods of patients with intraperitoneal bleeding of genital origin treatment objective efficacy assessment // Saratov Journal of Medical Scientific Research, Vol. 10, Issue 1, 2014, pp. 70-74

Background. Low-frequency (LF) oscillations in heart rate (HR) are largely an index of baroreflex gain. Controlled 0.1 Hz breathing maybe used as input stimuli for study of this resonance phenomenon in LF oscillations in HR. The aim of this study was the investigation of the dynamic characteristics of LF oscillations in the heart rate (HR) of chronic heart failure (CHF) patients during bicycle exercise (BE) tests, under 0.1 Hz controlled breathing. Methods. Forty five male patients aged 50±3 years with left ventricle ejection fraction (EF) <50% and 35 male patients aged 52±6 years with EF>50% participated in the study. BE tests were performed for all participants. Five-minute recording of R-R intervals was performed first in sedentary posture and in 25 W load stage of BE test. The frequency estimates of heart rate variability in LF spectrum bands were obtained. Results. Under the load rising till 25 W in CHF patients with EF<50%, consequent depression of LF band power was observed 2-3 times in comparison with the relaxed condition. There was no similar significant expressed dynamic in the group with EF>50%. Conclusions. The stability of LF oscillations in HR to low-intensity loads depends from the severity of myocardial contractility damage. The power dynamic of 0.1 Hz component of the heart rate variability spectrum may be considered an independent index of dynamic stability of the heart autonomic control in CHF patients.
Health Science Journal 2013; 7(1): 90-98.

Background: Selection of the optimal dose of beta-blocker treatment in myocardial infarction (MI) patients is problematic because of a lack of well-established guidelines. Methods: We evaluated changes in synchronization between 0.1 Hz oscillations in heart rate (HR) and plethysmographic peripheral microcirculation in response to a tilt-table test and to 3-month treatment with the highest tolerated beta-blocker (metoprolol) dose in 43 patients aged between 41 and 77 years with acute MI 6 months prior to the start of the study. Before the study the patients were treated with small doses of beta-blocker. Phase differences between HR and peripheral microcirculation oscillations were used to measure the degree of synchronization (S), and relative change in S from horizontal position was used to characterize the response to vertical tilt. Results: Two groups of MI patients matched for clinical characteristics were identified on the basis of the results. The first group was composed of patients with decreased S as a response to vertical tilt at the beginning of the study. The patients with increased S during vertical tilt before treatment with the highest tolerated beta-blocker dose were attributed to the second group. The response to vertical tilt in the first group of patients was postulated to indicate the need to increase beta-blocker dose, and in turn, the response in the second group to indicate an already adequate beta-blocker dose. Conclusion: Assessment of synchronization of 0.1 Hz HR and peripheral microcirculation oscillations as a response to a tilt test can possibly be used as a guideline for selecting beta-blocker dose in post-MI patients.
Journal of Cardiovascular Medicine 2012; 13(8): 491-498

Abstract—Biophysical features of 0.1Hz oscillations of heart rate variability (HRV) and distal blood flow (DBF) variability were compared in healthy subjects and patients after acute myocardial infarction (MI). Patients with acute MI (72 men and 53 women; 125 in total) and healthy subjects (23 men and 10 women; 33 in total) aged 30–38 and 20–46 years, respectively, participated in the study. The patients were involved in the study for a year after acute MI. The delay in coupling 0.1Hz oscillations of HRV and DBF variability was estimated. In healthy subjects, the delay in the heart DBF coupling proved to be less than the delay in the DBF heart coupling. Acute MI results mainly in disruption of the heart DBF coupling, which is par tially restored by the end of the first year after acute MI, though it remains lower than in healthy subjects. The DBF heart coupling is rapidly restored to the level of healthy subjects within three weeks after acute MI.
Human Physiology. 2012. Vol.38. Iss.3. P.303–309.

Aim: to estimate prognostic value of indicators of heart rhythm variability (HRV) in patients with chronic heart failure (CHF) within three years. Materials and methods: A total of 110 patients aged 55,2±6,5 years with CHF experienced Q-wave myocardial infarction were enrolled in the study. Analysis of HRV measures was obtained by means of 5 minutes records of standing at rest. Results: Within three years of supervision of patients 50 cases of cardiovascular complications were developed: 22 cases presented CHF regeneration, 13 patients suffered recurrent myocardial infarctions, lethal outcome was observed in 15 cases. It was established that at level of low-frequency spectrum HRV less than 5,2 In ms2 decompensations CHF (p=0,048) and lethal outcome (p=0,02) were determined than at bigger value of this indicator. Independent predictors of lethal outcome in patients with CHF within three years included the left ventricle ejection fraction, uric acid, N-terminal fragment of cerebral natriuretic peptide and low-frequency spectrum HRV. Conclusions: The developed algorithm of estimation of individual risk of lethal outcome development in CHF patients within three years, will allow to improve tactics and prognosis in this category of patients
Kosheleva N.A. Prognostic value of heart rhythm variability in patients with chronic heart failure (three-year investigation) // Saratov Journal of Medical Scientific Research, Vol. 7, Issue 4, 2011, pp. 845-850

The research goal is to study the correlation between indices of variational pulsometry, entropy of heart rate, temporal and spectral analyses and heart rate variability in healthy patients and patients with coronary heart disease. Materials. Of the study are indicators of variational pulsometry and temporal and spectral analyses from 111 patients with coronary heart disease and in 61 healthy individuals. Results. Most parameters of HRV correlated with each other. In healthy patients the greatest independence was characterized by Mo and LF/HF, in patients with coronary artery disease — only by LF/HF Significant correlation with SDNN RMSSD, TP, LF, HF was determined. Conclusion. The variational pulsometry, temporal and spectral analyses of HRV and entropy of heart rate provide HRV assessment. The indices are interdependent and indicate interchangeability of methods
Durnova N.Yu., Dovgalevskiy Ya.P., Burlaka A.N., Kiselev A. R., Furman N.V. Interdependence of parameters of varia-tional pulsometry, entropy of heart rate, temporal and spectral analyses of heart rate variability in normal state and in ischemic heart disease // Saratov Journal of Medical Scientific Research, Vol. 7, Issue 3, 2011, pp. 607-611

The aim was to study the suitability of the heart rate variability (HRV) spectral parameters for evaluations of bicycle ergometry results in coronary heart disease (CHD) patients. Methods. Our study included 243 male CHD patients aged 49±8 years. The coronary atherosclerosis was assessed by coronary angiography. The results of bicycle ergometry, Doppler echocardio-graphy and HRV spectral analysis were also analyzed. The duration of each stage of bicycle ergometry was 3 min, the initial load value was 25 W. Dynamic load continued until the patient had reached 75% of heart rate from his maximal age level. The maximal level of load achieved (i.e. load tolerance) was taken into consideration. We calculated sensitivity (Se), specificity (Sp), likelihood ratios of positive (LR+) and negative (LR-) bicycle ergometry results. Results. All patients had similar clinical characteristics. LR+ become maximal under the moderate load tolerance. LR- are maximal in the CHD patients with high load tolerance. Thus, the excessiveness of false-negative results of bicycle ergometry is in CHD patients with high load tolerance. Reliability of results of bicycle ergometry increased under using assessments of low-frequency (LF) range power of HRV spectrum. Conclusions. Thus,the using of LF range power of HRV spectrum increases reliability of bicycle ergometry (or other load tests) results in CHD patients.
Health. 2011. Vol. 3. No. 8. P.477-481.

Synchronization between 0.1 Hz oscillations in heart rate and blood pressure is studied and its change during vertical tilt is evaluated in 37 myocardial infarction patients. Two groups of patients are identified with decreased and increased, respectively, synchronization of the studied oscillations as a response to a tilt test. It is shown that assessment of synchronization of 0.1 Hz oscillations as a response to vertical tilt can be used as a guideline for selecting optimal dose of beta-blocker treatment in post-myocardial infarction patients.
Proceedings of World Academy of Science, Engineering and Technology. 2011. Vol. 76. P.367–372.

Aim: The aim was the studying of synchronization between 0.1 Hz oscillations in heart rate (HR) and plethysmographic peripheral microcirculation (PM) in acute myocardial infarction (AMI) patients and in healthy subjects. Material and Method: 12 healthy volunteers aged 26±5 years and 125 patients with AMI aged 65±9 years were involved in the study. Simultaneous registration of electrocardiogram and photoplethysmogram were performed during 10 min. In AMI patients the signals were recorded twice: the first record was done during 3-5 days after AMI, the second record was done during the third week after AMI. Phase differences between HR and PM oscillations were used to measure the degree of synchronization (S). Data are submitted as medians with inter-quartile ranges (25%, 75%). Results: S was 65.8% (50.5%; 79.5%) in healthy subjects whereas in AMI patients at the first week after AMI S was 16.3% (9.4%; 24.6%) (p<0.001). In records made at the third week after AMI index S was 18.4% (11.2%; 28.2%). Two groups of AMI patients were identified on the basis of individual S dynamics. In 100 AMI patients no dynamics of S was observed during the observation period and in 25 AMI patients the increase of S was observed. The group of AMI patients with increase of S had greater HR values during the first week after AMI. Conclusion: The index S of synchronization of 0.1 Hz oscillations in HR and PM appears to be a sensitive indicator of autonomic control dynamic disturbances in AMI patients.
Applied Medical Informatics. 2011. Vol. 28. Iss. 1. P. 1-8.