• Title/Summary/Keyword: Heart Work

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Modeling for the Work of Heart and Development of the WOH Medical device (심장운동부하 모델링과 의료장비 개발)

  • Roh, Hyung-Woon;Suh, Sang-Ho
    • 유체기계공업학회:학술대회논문집
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    • 2006.08a
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    • pp.501-504
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    • 2006
  • The estimation of the work of heart can be treated as one of the most important parameters for determining the amount of circulating blood needed for harmonious metabolism in the human body. By monitoring the work of heart, one can detect increased work load of heart and start the treatment at the early stage of CHF. Thus it is necessary to estimate the work of heart. The contractility of the left ventricle, the second important parameter for representing the motion of heart, can be estimated through information on the work of heart. In this study, the modified Windkessel model, which has been used for a measure of vascular hemodynamic impedance parameters, was adapted to estimate the work of heart.

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Work Load Dependency of Heart Rate Variability (HRV) (심박변이도의 운동부하 의존성)

  • Kwon J.H.;Kim C.S.;Eom G.M.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2006.05a
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    • pp.641-642
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    • 2006
  • The purpose of this work is to investigate the effect of work load on heart rate variability (HRV) which is widely used marker of the autonomic nervous system activity. Average heart rate, rating of perceived exertion, and the power spectrum of heart rate variability were investigated in seven healthy males during exercise at various work loads. The subjects were divided into two groups according to the average heart rate during exercise, group 1 with lower heart rate and group 2 with higher heart rate. HF component showed decrease followed by increase with workload. Accordingly, the LF/HF ratio showed increase followed by decrease with workload. The peak in LF/HF ratio of group 1 was at the lower workload than that of group 2.

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Comparison between Heart Rates and Borg's Scale as a Tool to Evaluate Physical Workload (작업 현장에서 육체적 작업 강도를 평가하는 도구로서 Borg's Scale과 심박 수의 비교)

  • Kim, Byoung Hoon;Park, Ji Young;Tak, Sangwoo
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.29 no.3
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    • pp.368-374
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    • 2019
  • Objectives: To examine the associations of borg's scale with actual heart rates of workers and energy consumption during their physical work. Methods: A total of 72 workers performing physical activities in postal service, ceramic manufacturing, and metal manufacturing participated in heart rate measurement for 1 work shift using the activity meter(A360) and responded to a borg's scale questionnaire. Results: In consistent with previous findings, we presented high correlation between borg's scale and energy consumption measures among workers performing physical activities(r=0.89) while post-work average heart rate showed nearly no correlation with post-work borg's scale (r=0.09). We proposed a set of adjustments when using borg's scale to estimate physical workload for those workers engaged in physical activities during the majority of their work shift. Conclusions: Our findings suggest that a caution should be paid to when using Borg's scale to estimate heart rates during physical activities as well as energy consumption as the product of heart rate measurements.

Changes in Total Work, Total Work Ratio, Heart Rate, and Blood Lactate during 75% 1-RM Bench Press Exercise

  • Kim, Ki Hong;Kim, Byung Kwan
    • Medical Lasers
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    • v.10 no.3
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    • pp.153-160
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    • 2021
  • Background and Objectives This study was conducted to investigate the change of total work and total work ratio for each set, peak heart rate during exercise, and blood lactate for each set during the 5-set bench press exercise at 75% one repetition maximum test (1-RM). Materials and Methods Seven men in their 20s with more than 6 months of experience doing resistance exercises were selected as subjects, and their 1-RM bench press was measured two weeks before the experiment and 75% 1-RM was measured one week before the experiment. In this study, total work was measured for each set, and heart rate was measured during rest and set-by-set exercise. Blood lactate was measured during rest time after each set. The raw data were analyzed by repeated one-way ANOVA. Results Total work and total work ratio decreased from 1 set to 4 sets (p < .05), p < .001), heart rate increased from stable at the start of exercise (p < .001) and decreased between 3 sets and 4 sets (p < .05). Blood lactate increased continuously up to 2 sets (p < .001, p < .01). Conclusion In conclusion, total work and heart rate decreased with muscle fatigue during exercise, and blood lactate continuously increased. The results of this study are expected to be useful references for constructing resistance exercise programs in the future.

Global Left Ventricular Myocardial Work Efficiency in Patients With Severe Rheumatic Mitral Stenosis and Preserved Left Ventricular Ejection Fraction

  • Estu Rudiktyo;Amiliana M Soesanto;Maarten J Cramer;Emir Yonas;Arco J Teske;Bambang B Siswanto;Pieter A Doevendans
    • Journal of Cardiovascular Imaging
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    • v.31 no.4
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    • pp.191-199
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    • 2023
  • BACKGROUND: Assessment of left ventricular (LV) function plays a pivotal role in the management of patients with valvular heart disease, including those caused by rheumatic heart disease. Noninvasive LV pressure-strain loop analysis is emerging as a new echocardiographic method to evaluate global LV systolic function, integrating longitudinal strain by speckle-tracking analysis and noninvasively measured blood pressure to estimate myocardial work. The aim of this study was to characterize global LV myocardial work efficiency in patients with severe rheumatic mitral stenosis (MS) with preserved ejection fraction (EF). METHODS: We retrospectively included adult patients with severe rheumatic MS with preserved EF (> 50%) and sinus rhythm. Healthy individuals without structural heart disease were included as a control group. Global LV myocardial work efficiency was estimated with a proprietary algorithm from speckle-tracking strain analyses, as well as noninvasive blood pressure measurements. RESULTS: A total of 45 individuals with isolated severe rheumatic MS with sinus rhythm and 45 healthy individuals were included. In healthy individuals without structural heart disease, the mean global LV myocardial work efficiency was 96% (standard deviation [SD], 2), Compared with healthy individuals, median global LV myocardial work efficiency was significantly worse in MS patients (89%; SD, 4; p < 0.001) although the LVEF was similar. CONCLUSIONS: Individuals with isolated severe rheumatic MS and preserved EF, had global LV myocardial work efficiencies lower than normal controls.

A Clinical Study for Return to Work after Heart Valve Replacement - A Case Report - (심장판막 치환술후 직업복귀에 대한 임상적 고찰)

  • 김현경
    • Journal of Chest Surgery
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    • v.24 no.10
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    • pp.967-972
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    • 1991
  • Between Feb. 1982 and July 1990, 173 patients [male: 89, female: 84] Who underwent heart valve replacement for acquired valvular heart disease on the Department of Thoracic and Cardiovascular Surgery, School of Medicine, Pusan National University, were reviewed for return to work after heart valve replacement. The replaced valve were mitral [128, 74.0%], aortic[10, 5.8%], mitral & aortic[35, 20.2%]. Two tricuspid valve replacement were excluded. Several important factors influencing the return to work were age, the employment status before surgery, the number of replaced valve, the pre - op NYHA functional class and cardiac function [ejection fraction]. These factors were closely related to the optimal time of heart valve replacement. It can be concluded that the rate of return to work and the quality of life would be improved if valve replacement were performed at an earlier stage of valvular heart disease.

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Mathematical Modeling for Estimation of Heart Work (심장 일의 측정을 위한 수학적 모델링)

  • Suh, Sang-Ho;Kaptan, Yalin;Roh, Hyung-Woon;Song, Ji-Hoon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.36 no.2
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    • pp.145-151
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    • 2012
  • Evaluation of the heart work is starting to emerge as a new diagnostic tool for arterial diseases. The aim of this study is to develop a mathematical model for the estimation of heart work utilizing the pulse waves between two points of a vessel. In order to calculate heart work, medical data such as blood pressure waveforms (which are measured using a cuff) are utilized. The heart work is calculated by employing the modified Windkessel model together with the viscosity models of Casson or Herschel-Bulkely (H-B). The results indicate that the compliance values at the proximal and distal locations differ for the Casson and H-B models.

The Effect of Boshimdan(補心丹:$\breve{b}ux\bar{i}nd\bar{a}n$) on Ischemic Heart Disease (허혈성(虛血性) 심근(心筋)에 보심단(補心丹)이 미치는 영향(影響))

  • Gang, Myeong-Seok;Go, Chang-Nam;Jo, Gi-Ho;Kim, Yeong-Seok;Bae, Hyeong-Seop;Lee, Gyeong-Seop
    • The Journal of Internal Korean Medicine
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    • v.16 no.2
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    • pp.61-73
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    • 1995
  • In this study, the effects of Boshimdan, which is used in oriental medicine for the treatment of palpitation, chest discomfort, impatience, insomnia, forgetfulness ete., were tested as a part of series of experimental verification of prescriptions treatments for preventing and curing ischemic heart. The results were as follows: 1. Boshimdan did not effectively work on heart rate of the perfused rat heart. 2. Boshimdan did not effectively work on heart pressure of the perfused rat heart. 3. Boshimdan did not effectively work on flow rate of the perfused rat heart. 4. Boshimdan was not effective in activation of GOT. 5. Boshimdan was not effective in activation of GPT. 6. Boshimdan was not effective in activation of LDH. 7. Boshimdan was not effective in activation of CPK.

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Cardiac Performance of Turtle Heart in Various pH of Perfusate (자라에서 본 관류액(灌流液) pH와 심장박출량(心臟搏出量))

  • Yang, Il-Suk
    • The Korean Journal of Physiology
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    • v.9 no.1
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    • pp.69-76
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    • 1975
  • Cardiac performances were analyzed in intact turtle heart(Amyda japonica), perfusing with turtle Ringer-Locke's solution containing various hydrogen ion concentration, at several levels of arterial and venous pressure. 1. Ventricular work increased when venous pressure, or venous filling pressure increased, and also increased when arterial pressure increased. 2. The higher the arterial pressure, the lower the cardiac to output, for arterial pressure is the resistance to the ventricular blood flow. On the other hand, in specific arterial pressure, cardiac output was proportional to the venous filling pressure. 3. Heart rates did not change significantly during the perfusion with Ringel· solution of various pH. 4. In the heart Perfused with Ringer solution of various pH, ventricular work was the highest at PH 7.6 (at 6 $cmH_2O$ arterial pressure and 8 $cmH_2O$ venous pressure, the ventricular work was 63.09m$\cdot$cm). However, within the range of pH $7.1{\sim}7.6$, there were no significant changes in cardiac output and ventricular work. Below the level of pH 7.0, ventricular work decreased to less than 56% of maximium value (at $6cmH_2O$ arterial pressure and $8cmH_2O$ venous Pressure, ventricular work was 36.0$gm{\cdot}$ at pH 7.0). At pH 7.7 ventricular work decreased to less than 48% of maximum value (ventricular work: 30.0 $gm{\cdot}$). The nature of the cardiac performance at the various arterial and venous pressures was similar to that of normal heart. 5. Turtle heart seemed to be relatively insensitive to acid-base disturbances. The mechanism of negative inotropic effect of hydrogen ion was discussed.

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Development of a Model for Physiological Safe Work Load from a Model of Metabolic Energy for Manual Materials Handling Tasks (에너지 대사량을 고려한 인력물자취급시의 생리적 안전 작업하중 모델 개발)

  • Kim Hong-Ki
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.27 no.3
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    • pp.90-96
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    • 2004
  • The objective of this study was to develop a model for safe work load based on a physiological model of metabolic energy of manual material handling tasks. Fifteen male subjects voluntarily participated in this study. Lifting activities with four different weights, 0, 8, 16, 24kg, and four different working frequencies (2, 5, 8, 11 lifts/min) for a lifting range from floor to the knuckle height of 76cm were considered. Oxygen consumption rates and heart rates were measured during the performance of sixteen different lifting activities. Simplified predictive equations for estimating the oxygen consumption rate and the heart rate were developed. The oxygen consumption rate and the heart rate could be expressed as a function of task variables; frequency and the weight of the load, and a personal variable, body weight, and their interactions. The coefficients of determination ($r^2$) of the model were 0.9777 and 0.9784, respectively, for the oxygen consumption rate and the heart rate. The model of oxygen consumption rate was modified to estimate the work load for the given oxygen consumption rate. The overall absolute percent errors of the validation of this equation for work load with the original data set was 39.03%. The overall absolute percent errors were much larger than this for the two models based on the US population. The models for the oxygen consumption rate and for the work load developed in this study work better than the two models based on the US population. However, without considering the biomechanical approach, the developed model for the work load and the two US models are not recommended to estimate the work loads for low frequent lifting activities.