Analysis of cardiac rhythm variability in Jersey breed cows with different vegetative status

Purpose: Conduct an analysis of cardiac rhythm variability in the cows of the Jersey breed with a different vegetative status.Materials and methods. Indicators of the electrocardiogram (ECG) and cardiac rhythm variability studied on cows of the Jersey breed (n = 103). For the analysis and removal of ECG, the animal studied used the program «Conan-4.5» in the system of frontal administrations according to the method of P. M. Roshchensky. Clinical research methods were carried out according to the methods of clinical inspection of animals B. V. Ears and included — inspection, palpation, percussion and auscultation of the heart area.Results. Among the entire studied array of animals, the largest amount was sympathyone — 50,5%, normotonics — 24,3%, hypersympathicotonics — 16,5%. The smallest amount — vagotonic — 8,7%. For the vagotonic, the respiratory modulation index was 8,16±0,02%, the index of the sympathetic system is 43±0,1%, and the index of slowly wave arrhythmia is 0,8±0,1%. This group of cows parasympathetic (software) prevails over the sympathetic department of the vegetative nervous system. For normotonics, the value of the respiratory modulation index was 4,14±0,03%, the index of the sympathetic system is 96±0,2%, and im is 2,5±0,2%. This group is characterized by an equilibrium state between sympathetic department and VNS. The ids for sympathicotonists amounted to 2,78±0,03%, the index of the sympathetic system is 195±0,2%, and im is 8,2±0,1%. At sympathicotonists, which are characterized by a predominance with VNS above software. The hyper smpathetical respiratory modulation index was 1,34±0,02%, ICAS — 588±0,1%, and im is 11,4±0,3%. In hypersympathicotonists, which are characterized by the predominance of the super-viper vehicle of the vegetative nervous system over parasympathetic.Conclusion. The separation of the entire array on the subgroups based on the vegetative status of animals was based on the indicators of the voltage index of regulatory systems. To confirm the correctness of the separation of the studied array of animals on the subgroup, statistical processing was carried out and a classification matrix was built. Also, to confirm the classification separation matrix, additional statistical processing of the material of the differences between the obtained groups in the square of the distance of the Mahalonobis D2 was carried out. In the course of further registration and mathematical analysis of the variability of the heart rate of cattle (cows of the Jersey breed) with the help of a modern complex electrophysiological laboratory «Conan-4.5» features of indexes of A. Ya. Kaplan were established.

Respiratory Induced Modulation in f-Wave Characteristics During Atrial Fibrillation

The autonomic nervous system (ANS) is an important factor in cardiac arrhythmia, and information about ANS activity during atrial fibrillation (AF) may contribute to personalized treatment. In this study we aim to quantify respiratory modulation in the f-wave frequency trend from resting ECG. First, an f-wave signal is extracted from the ECG by QRST cancelation. Second, an f-wave model is fitted to the f-wave signal to obtain a high resolution f-wave frequency trend and an index for signal quality control (S). Third, respiratory modulation in the f-wave frequency trend is extracted by applying a narrow band-pass filter. The center frequency of the band-pass filter is determined by the respiration rate. Respiration rate is estimated from a surrogate respiration signal, obtained from the ECG using homomorphic filtering. Peak conditioned spectral averaging, where spectra of sufficient quality from different leads are averaged, is employed to obtain a robust estimate of the respiration rate. The envelope of the filtered f-wave frequency trend is used to quantify the magnitude of respiratory induced f-wave frequency modulation. The proposed methodology is evaluated using simulated f-wave signals obtained using a sinusoidal harmonic model. Results from simulated signals show that the magnitude of the respiratory modulation is accurately estimated, quantified by an error below 0.01 Hz, if the signal quality is sufficient (S>0.5). The proposed method was applied to analyze ECG data from eight pacemaker patients with permanent AF recorded at baseline, during controlled respiration, and during controlled respiration after injection of atropine, respectively. The magnitude of the respiratory induce f-wave frequency modulation was 0.15 ± 0.01, 0.18 ± 0.02, and 0.17 ± 0.03 Hz during baseline, controlled respiration, and post-atropine, respectively. Our results suggest that parasympathetic regulation affects the magnitude of respiratory induced f-wave frequency modulation.

Respiratory coupling between prefrontal cortex and hippocampus of rats anesthetized with urethane in theta and non-theta states

Respiratory modulation of forebrain activity, long considered hard to reliably separate from breathing artifacts, has been firmly established in recent years using a variety of advanced techniques. Respiratory related oscillation (RRO) is derived from rhythmic nasal airflow in the olfactory bulb (OB) and is conveyed to higher order brain networks, including the prefrontal cortex (PFC) and hippocampus (HC), where it may potentially contribute to communication between these structures by synchronizing their activities at the respiratory rate. RRO was shown to change with sleep-wake states, it is strongest in quiet waking, somewhat less in active waking, characterized with theta activity in the HC, and absent in sleep. The goal of this study was to test RRO synchronization between PFC and HC under urethane anesthesia where theta and non-theta states spontaneously alternate. We found that in theta states, PFC-HC coherences significantly correlated with OB-HC but not with OB-PFC, even though RRO was stronger in PFC than in HC. In non-theta states, PFC-HC synchrony correlated with coherences connecting OB to either PFC or HC. Thus, similar to freely behaving rats, PFC-HC synchrony at RRO was primarily dependent on the response of HC to the common rhythmic drive, but only in theta state. The findings help outlining the value and the limits of applications in which urethane-anesthetized rats can be used for modeling the neural mechanisms of RRO in behaving animals.

After-Discharge in the Upper Airway Muscle Genioglossus Following Brief Hypoxia

Study Objectives Genioglossus after-discharge is thought to protect against pharyngeal collapse by minimising periods of low upper airway muscle activity. How genioglossus after-discharge occurs and which single motor units (SMUs) are responsible for the phenomenon are unknown. The aim of this study was to investigate genioglossal after-discharge. Methods During wakefulness, after-discharge was elicited 8-12 times in healthy individuals with brief isocapnic hypoxia (45-60s of 10%O2 in N2) terminated by a single breath of 100% O2. Genioglossus SMUs were designated as firing solely, or at increased rate, during inspiration (Inspiratory phasic [IP] and inspiratory tonic [IT] respectively); solely, or at increased rate, during expiration (Expiratory phasic [EP] or expiratory tonic [ET] respectively) or firing constantly without respiratory modulation (Tonic). SMUs were quantified at baseline, the end of hypoxia, the hyperoxic breath and the following 8 normoxic breaths. Results 210 SMU’s were identified in 17 participants. Genioglossus muscle activity was elevated above baseline for 7 breaths after hyperoxia (p<0.001), indicating a strong after-discharge effect. After-discharge occurred due to persistent firing of IP and IT units that were recruited during hypoxia, with minimal changes in ET, EP or Tonic SMUs. The firing frequency of units that were already active changed minimally during hypoxia or the afterdischarge period (P>0.05). Conclusion That genioglossal after-discharge is almost entirely due to persistent firing of previously silent inspiratory SMUs provides insight into the mechanisms responsible for the phenomenon and supports the hypothesis that the inspiratory and expiratory/tonic motor units within the muscle have idiosyncratic functions.

Heart rate variability, indicators of Kaplan indices in healthy dogs

The study of indicators of Kaplan indices in dogs has not been previously conducted and their normal values are not described in the available literature. Given the subtlety of the mechanisms of autonomic regulation of the heart, there is a need to expand the diagnostic base for very common heart diseases in dogs.The aim of the research is to study the Kaplan indices in dogs to assess the possibility of including them in an integrated approach to the analysis of the functioning of the heart in dogs. 74 healthy dogs were examined. The dependence of changes in the Kaplan indices on age was studied. An asymmetric distribution of Kaplan indices in the studied group of dogs was established. Intervalograms were recorded using a computerized polygraphic amplifier "MKS KARDi2-NP" (Russia). Recording was performed on dogs in a resting state, standing or sitting. To analyze the obtained intervalograms, to obtain the values of the Kaplan indices, the integrated instrumental-methodological complex "CONAN" was used.The following Kaplan indices have been studied: Respiratory modulation index (IDM); Sympathoadrenal Tone Index (SAT); Slow-wave arrhythmia index (IMA).The normal values of Kaplan's indices were established: IDM, SAT, IMA for dogs. In this regard, the assessment of these indices should be included in the basic set of methods for diagnosing heart disease in dogs. The absence of dependence of changes in indices on age in dogs was found. The lack of research on Kaplan indices requires additional research in groups of different weight on a representative sample.

Respiratory rate modulation improves symptoms in patients with pulmonary hypertension

Background: Pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension are chronic diseases with a severe symptom burden. Common symptoms are dyspnoea at light activity and general fatigue that limits daily activities. Respiratory modulation by device-guided breathing decreased symptoms in patients with heart failure. The aim of this pilot study was to investigate if respiratory modulation could improve symptoms of dyspnoea in patients with pulmonary arterial hypertension or chronic thromboembolic pulmonary hypertension. Method: Adult patients with pulmonary arterial hypertension or chronic thromboembolic pulmonary hypertension with symptoms of dyspnoea at rest or light activity performed home-based respiratory modulation by device-guided breathing 20 min a day for 3 months. Patients were on stable disease-specific treatment ⩾3 months and willing to undergo all study procedures. Dyspnoea score, World Health Organization class, physical status, N-terminal pro b-type natriuretic peptide, quality of life, respiratory rate and 6-min walk distance were assessed before and after 3 months with respiratory modulation. Results: Nine patients with pulmonary arterial hypertension and five with chronic thromboembolic pulmonary hypertension completed the study protocol. Mean age was 71 ± 14 years, and 11 were women. After 3 months of respiratory modulation, dyspnoea score (−0.6, p = 0.014), respiratory rate at rest (−3 breaths/min, p = 0.013), World Health Organization class (−0.3, p = 0.040), quality of life (EuroQol Visual Analogue Scale +5 points, not significant) and decreased N-terminal pro b-type natriuretic peptide (−163 ng/L, p = 0.043) had improved. The fatigue and respiratory rate after the 6-min walk decreased while the 6-min walk distance remained unchanged. Conclusion: Patients with pulmonary arterial hypertension or chronic thromboembolic pulmonary hypertension that used device-guided breathing for 3 months improved symptoms of dyspnoea and lowered the respiratory rate at rest and after exercise.