Deriving electrophysiological phenotypes of paroxysmal atrial fibrillation based on the characteristics of heart rate variability

Aim. To analyze heart rate variability of patients with paroxysmal atrial fibrillation and identify electrophysiological phenotypes of the disease by using methods of exploratory analysis of twenty-four-hour electrocardiographic (Holter) recordings. Methods. 64 electrocardiogram recordings of patients with paroxysmal atrial fibrillation were selected from the open Long-Term Atrial Fibrillation Database (repository PhysioNet). 52 indices of heart rhythm variability were calculated for each recording, including new heart rate fragmentation and asymmetry indices proposed in the last 5 years. Data analysis was carried out with machine learning methods: dimensionality reduction with principal component analysis, hierarchical clustering and outlier detection. Feature correlation was checked by the Pearson criterion, the selected patients subgroups were confirmed by using MannWhitney and Student's tests. Results. For the vast majority of patients with paroxysmal atrial fibrillation, heart rate variability can be described by five parameters. Each of these parameters captures a distinct approach in heart rate variability classification: dispersion characteristics of interbeat intervals, frequency characteristics of interbeat intervals, measurements of heart rate fragmentation, indices based on heart rate asymmetry, mean and median of interbeat intervals. Two large phenotypes of the disease were derived based on these parameters: the first phenotype is a vagotonic profile with a significant increase of linear parasympathetic indices and paroxysmal atrial fibrillation lasting longer than 4.5 hours; the second phenotype with increased sympathetic indices, low parasympathetic indices and paroxysms lasting up to 4.5 hours. Conclusion. Our findings indicate the potential of nonlinear analysis in the study of heart rate variability and demonstrate the feasibility of further integration of nonlinear indices for arrhythmia phenotyping.

Early Predictors of Heart Failure Progression in Patients After Myocardial Infarction

Aim To identify early predictors for progression of chronic heart failure (CHF) in patients with ST-segment elevation myocardial infarction (STEMI).Material and methods The study included 113 patients with STEMI aged 52 (95 % confidence interval, 36 to 65) years. 24-h ECG monitoring was performed with assessment of ventricular late potentials, QT dispersion, heart rhythm turbulence (HRT), and heart rhythm variability (HRV); XStrain 2D echocardiograpy with determination of volumetric parameters, myocardial strain characteristics and velocities; and measurement of brain natriuretic peptide (BNP) concentrations. The endpoint was CHF progression during 48 weeks of follow-up, which was observed in 26 (23 %) patients. Based on the outcome, two groups were isolated, with CHF progression (Prg) (26(23%)) and with a relatively stable CHF postinfarction course (Stb) (87 (77 %)).Results At 12 weeks following MI, the Prg group showed increases in left ventricular (LV) end-diastolic dimension (EDD) (р<0.05) and end-diastolic and end-systolic volumes (EDV, ESV), (р<0.01), and EDV and ESV indexes (EDVi and ESVi, р<0.01). In this group, global longitudinal strain (GLS) was decreased at 24 weeks (р<0.05) and global radial strain (GRS) was decreased at 48 weeks (р=0.0003). In the Prg group, values of strain parameters (GLS, global circular strain (GCS), and GRS) were lower at all times. At 7-9 days, 24 weeks, and 48 weeks, the proportion of patients with pathological HRT was higher in the Prg group (38, 27, and 19 % for the Prg group vs 14 % (р=0.006); 3,4 % (р=0.001), and 2.3 % (р=0.002) for the Stb group, respectively). Only in the Stb group, increases in HRV were observed (SDNNi by 13 % (р=0.001), rMSSD by 24 % (р=0.0002), TotP by 49 % (р=0.00002), VLfP by 23 % (р=0.003), LfP by 22 % (р=0.008), and HfP by 77 % (р=0.002). At 7-9 days of MI, the Stb group had greater values of SDANN (р=0.013) and HfP (р=0.01). CHF progression correlated with abnormal values of turbulence onset (TO), disturbed HRT, increased BNP levels and LV ESD, and low values of GLS, GCS, and GRS. Combined assessment of HRT, LV ESD, and GLS at 7–9 days after STEMI allows identifying patients with high risk for CHF progression in the next 48 weeks.Conclusion The markers for CHF progression after STEMI include abnormal TO values, disturbed HRT, increased BNP levels and LV ESD, and low values of GLS, GCS, and GRS. The multifactor logistic regression analysis revealed early predictors of CHF in the postinfarction period, including abnormal TO, increased LV ESD, and reduced GLS.

Preparation of Silver Nanoparticle Composite Material and Its Role in Electrocardiogram Treatment of Acute Myocardial Infarction

The surface resonance scattering of silver nanoparticles, commonly used to enhance the matrix of the Raman, is the most active of all metal nano particles which can greatly improve the sensitivity of the detected molecules. At the same time, the sterilization ability of silver is also highly recommended in the field of biology. In this study, cytosine nucleoside was used as a template to quickly synthesize silver-based composite nanomaterials (Ag–C/Au) with enhanced fluorescence and good water solubility. Then, the fluorescence spectrum, lifetime, the ultraviolet-visible absorption spectrum of the material, and the size and shape of the grain size were studied through characterization. After that, the interaction between the silver-based composite nanomaterial Ag–C/Au and the recombinant protein ephrin-b2 was studied by spectroscopy, and the mixed metalloprotein was used for electrocardiogram treatment of myocardial infarction in SD rats to establish a rat modeling, then the rats were grouped according to the different injections, and the heart rhythm variability (HRV) of different groups of rats with myocardial infarction (MI) was recorded. Finally, the program electrical stimulation (PES) was used to analyze the ventricular effective refractory period (VERP) and ventricular arrhythmia (VAs) in rats. In the experiment, Ag–C/Au nanomaterials produced strong yellow fluorescence under 370 nm ultraviolet excitation, with an approximate particle size of 1.6 nm; through spectral data fitting, it was found that the recombinant protein ephrin-b2 could be adsorbed on the surface of the composite nanomaterials, making the intensity of the characteristic peak decreased; the myocardial indicators of myocardial infarction rats based on ephrin- b2 + Ag–C/Au group were significantly improved, while the grouping of rats using Ag–C/Au alone didn't affect the electrophysiological characteristics after myocardial infarction, that is, ephrin-b2 could improve arrhythmia after myocardial infarction, and the improvement effect would be further strengthened when Ag–C/Au was added.

Disturbances of Autonomic Regulation of Cardiovascular System at Different Working Regimes with Night Shifts

Aim To study temporal and spectral characteristics of heart rhythm variability (HRV) in night shift workers.Materials and methods Along with traditional risk factors, conditions of labor contribute to development of cardiovascular morbidity, including night shift work, which can be associated with disorders of the autonomic regulation detected by analysis of HRV. This study included 100 healthy men. 74 of them were engaged in shift work, including 53 men with rotating shift work, 21 men with fixed night shifts, and 26 men with day-time work. HRV was analyzed by data of 5-min electrocardiogram recording (background recording and orthostatic test).Results Night-shift workers had decreases in total power of regulation (ТР, SDNN) and in the parasympathetic branch (HF, pNN50). Rotating night-shift workers displayed significant decreases in SDNN and pNN50 and pronounced changes in the VLF / LF / HF ratio in the orthostatic test.Conclusion In work with night shifts, the type of autonomic regulation differs from the “standard” functioning of the autonomic nervous system (ANS). This study showed different effects of night work regimens on HRV indexes. With the rotating shift work, the ANS dysregulation was more profound and was evident by a significant decrease in the ANS total tone and parasympathetic activity (SDNN, pNN50) compared to night shifts with fixed working hours. The excessive weakening of the parasympathetic component in the passive orthostatic test can be considered as an early marker for ANS maladaptation.

Functiоnal Deviatiоns оf Vegetative Nervоus System in Girls with Gynaecоlоgical Pathоlоgy and their Dynamics under the Influence оf Sanatоrium Treatment

Purpose. Detectiоn and cоrrectiоn оf vegetative deviatiоns in girls with impaired menstrual functiоn, inflammatоry diseases оf appendages, after оperative interventiоns abоut cysts at the stage оf sanatоrium treatment. Materials and methоds. Clinical-functiоnal studies were carried оut in dynamics, including assessment оf the state оf vegetative regulatiоn by spectral analysis оf heart rhythm variability, catechоlamine urine hоrmоnes. Results. Under supervisiоn there were 126 girls between the ages оf 9 and 15 whо arrived fоr sanatоrium treatment. Perfоrmed sanatоrium treatment: 66 girls with menstrual functiоn disоrders including pyrecetam electrоphоresis by eye-оccipital methоd against the backgrоund оf sanatоrium regime, LFC, 32 girls with inflammatоry diseases оf pelvic оrgans receiving SMT – Phоresis оf the mud sоlutiоn оn the abdоminal bоttоm, micrоclysms with sage, 28 girls after gynaecоlоgical оperatiоns receiving laser therapy оn the оvarian area, phоnоphоresis оn the abdоminal bоttоm and lоcal therapy in the fоrm оf micrоclysms with sage allоwed tо оbtain a favоrable effect оf the functiоnal state оf BHS, first оf all, due to reductiоn оf the impact оn the BDR оf the central humоral-metabоlic cоmpоnent, reductiоn of excessive activity. Cоnclusiоns. The effectiveness оf sanatоrium and spa treatment оf girls with gynecоlоgical pathоlоgy with menstrual cycle disоrders, inflammatоry diseases оf pelvic оrgans and after gynecоlоgical оperatiоns depends оn the individual purpоse оf the therapeutic cоmplex taking intо accоunt the expressiоn оf deviatiоns оf the state оf the vegetative nervоus system.

Neural network analysis of heart rhythm variability for diagnosis of immobilization syndrome and objectivization of effectiveness of early rehabilitation

The article discusses the use of a neural network analysis of heart rate variability for the diagnosis of immobilization syndrome and post-intensive care syndrome (PICS) in patients with disorders of consciousness for monitoring the quality of the rehabilitation process. It is shown that there are statistical differences between the curves characterizing the heart rate variability of healthy patients and patients with impaired consciousness. The use of a neural network allows to automatically evaluate the severity of the immobilization syndrome and Post Intensive Care Syndrome, as well as the effectiveness of measures for their prevention and the overall quality of the work of medical personnel.

FEATURES OF DIAGNOSTICS OF SINUS ARRHYTHMIA IN YOUNG ATHLETES

In 47 young athletes with sinus bradycardia, levels of MB-creatine phosphokinase (MB-KFC) activity in blood serum and the state of the main spectral parameters of heart rhythm variability were studied. It has been stated that in asympatikotinic vegetative dysfunction the decrease in energy exchange is accompanied by bradycardia of an unstable character. Stable bradycardia, combined with high energy availability, is inherent in athletes without dystonia of the vagotonic type.

CORRELATION ANALYSIS OF INDICATORS OF ELECTROENCEPHALOGRAPHY AND VARIABILITY OF THE HEART RHYTHM IN SEAFARERS OVER TIME DURING THE ARCTIC VOYAGE

Introduction. The paper presents a correlation analysis between indicators of variability of heart rhythm and electroencephalogram among professional seafarers and expedition members who first set out on an Arctic voyage. The purpose of the work is to evaluate the compensatory-adaptive reactions of the brain and autonomic regulation of heart in seafarers and expedition members in the Arctic.Material and methods. Studies were carried out among groups of men of research vessels and expedition members of the Northern (Arctic) Federal University (NArFU) in the amount of 70 people. The subjects were divided into two groups – these are seafarers of the Professor Molchanov research vessel and the Neotrazimy marine rescue tugboat, as well as members of the NArFU expedition who participated in the Arctic marine expedition for the first time. To solve the tasks at the same time, an electroencephalogram (EEG) and heart rhythm variability (HRV) were measured at the beginning of the voyage (65 N) and at the end on the 20–30th day (78 N). Subsequently, a statistical analysis of the indicators and the calculation of correlations between groups were carried out.The results of the study showed that at the beginning of the flight, the subjects had high indicators of regulating body systems, due to the specifics of the influence of negative factors in the high latitudes of the Arctic. However, by the end of the month, a tendency towards a decrease in indicators of cardiac activity regulation and central nervous system (CNS) was observed in the group of seafarers. The obtained correlation relationships between the indicators can be used to control the adaptation of seafarers who first set out on an Arctic voyage.