The aortic elasticity in hearing-impaired girls after dynamic load

© 2019 by Advance Scientific Research. Persons with hearing impairments are a fairly large group of people whose physiological characteristics are poorly understood. Particular attention should be paid to the state of their cardiovascular system due to the fact that the body of a hearing-impaired person develops in reduced motor activity. When measuring hemodynamic parameters in real-time using an ultrasound monitor in girls with varying degrees of hearing loss, differences were revealed compared with those of normally hearing girls. We analyzed the following hemodynamic parameters at rest and after dynamic loading: aortic compliance (C), mean pressure gradient in aorta (Pmn), pulse arterial pressure (BPp), peak velocity (Vpk), and stroke volume variation (SVV). Higher values of mean pressure gradient in aorta, pulse blood pressure, and peak velocity after dynamic loading were obtained. Differences in the dynamics of aortic compliance indicator values were revealed. An assessment of aortic elasticity in girls with hearing impairment is given. These studies can be used during medical examinations in people with disabilities; when compiling guides for doctors and specialists in cardiology and functional diagnostics; in the preparation of teaching aids for specialists in age and sports physiology, teachers and trainers of specialized boarding schools for hearing-impaired and deaf children

The heart contractility of hearing-impaired young people under static load

© 2019 by Advance Scientific Research. The contractile function of the heart is controlled by the autonomic nervous system. The reaction of the contractile function of the heart to physical activity clearly demonstrates the features of the regulation of the cardiovascular system. In the modern way of life, the response of the body's systems to static loads is of particular importance. It is necessary to conduct regular diagnostics of the state of the cardiovascular system of hearing-impaired people due to the fact that their body develops under reduced physical activity and is exposed to mainly static loads. Diagnosis of hemodynamic parameters using an ultrasound monitor in young men with varying degrees of hearing loss revealed differences compared with healthy young men. We studied the following hemodynamic parameters at rest and after the static load: stroke volume (SV), cardiac output (CO), stroke work (SW), cardiac power (CPO). Higher values of these indicators were recorded at rest (except for SW) and after the static load. Signs of the predominance of the influence of the sympathetic nervous system on the regulation of hemodynamics in young people with hearing pathology were recorded. The reaction of the contractility of the heart in young people with hearing impairments was evaluated. These studies can be used during medical examinations in people with disabilities; when compiling guides for doctors and specialists in cardiology and functional diagnostics; in the preparation of teaching aids for specialists in age and sports physiology

Influence of HCN channels on isolated heart functions in adult rats

Heart pacemaking has triggered a research interest for many decades. Hyperpolarization-activated currents (If) and ion channels (HCN channels) that provide this current are widespread in the central and peripheral nervous system. In atypical cardiomyocytes, HCN channels generate a spontaneous electrical activity. The physiological role of HCN channels in the working myocardium remains a subject of constant research. The expression of HCN channels in cardiomyocytes of the ventricles was shown. It is possible that If participates in the formation of the potential action of working cardiomyocytes and, consequently, in the regulation of the inotropic cardiac function. The study was performed in order to investigate the role of hyperpolarization-activated currents on chronotropy, inotropy, and coronary flow of the Langendorff heart in adult rats. Experiments ex vivo were performed on random-bred albino rats aged 20 weeks. The heart was perfused in the Langendorff System (ADInstruments). The coronary flow, left ventricular pressure, and heart rate were calculated along the curve. 10–9 – 3?10–5 М concentrations range of ZD7288 (Sigma) were used for If blockade. The analysis of the results demonstrated that the left ventricular pressure increased after the blockade of If at the concentration of 10–9 M and decreased with the blocker concentration of 3?10–5 M. The ZD7288 caused bradycardia of the isolated heart at the concentrations of 10–9, 10–6, 3?10–5 M. The isolated heart coronary flow decreased with the blockade of If at the concentration of 10–9 M and 3?10–5 M. It was concluded that If blockade changes chronotropy, inotropy, and coronary flow of the isolated heart in adult rats