• Journal of Biomedical Engineering Research
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• v.44 no.4
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• pp.284-292
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• 2023

This study attempted to observe muscle activity and muscle fatigue among isotonic exercise of Biceps Brachii and Deltoidus Medius, which correspond to upper limb muscles, using metronome. For the experiment, 13 adult men participated to evaluate biosignals (ECG, EMG). For quantitative evaluation, 1RM and MVIC test were carried out and a constant pace isotonic excise session was conducted. Five sets of exercise were performed, and each set proceeded to the failure point while the speed condition (30bpm) was assigned. As a result of the experiment, muscle activity in both muscles was significantly reduced in fifth set compared to first set. Muscle fatigue has been confirmed to occur at a significant level within the set, but there was only a significant difference in both muscles in the first and second sets between sets. This is similar to the results of previous studies that gives the same rest time(2min), but further research is needed to see if the conditions for the number of repetitions are affected. Based on the recent increase of interest in muscle strength exercise, this study was conducted to observe the results by varying the conditions of common exercise.

• The Korean Journal of Nuclear Medicine
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• v.33 no.1
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• pp.40-48
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• 1999

Purpose: The sensitivity of ST-depression in the electrocardiogram during exercise is influenced by the level of efforts. However, unlike the prevalence of ST-depression on exercise ECG, the degree of exercise is reported to do not influence the diagnostic ability of myocardial perfusion scan. Furthermore, the relation between the prevalence of myocardial ischemia and effort is still controversial. We evaluated the effect of the degree of exercise on the ability of SPECT imaging to detect coronary artery stenosis. Materials and Methods: The patient population was comprised of 111 patients (73 men and 38 women, mean age 56 years) who underwent an exercise test in conjunction with Tc-99m MIBI and cardiac catheterization within 3 months apart each other. The degree of exercise was classified into four groups according to the percentage of maximal predicted heart rate. The sensitivity and specificity was compared between each group. Results: The overall diagnostic sensitivity was significantly higher with Tc-99m MIBI SPECT than exercise ECG. The specificity was not significantly different between two tests. Sensitivity and specificity of Tc-99m MIBI was not different between four groups. Sensitivity for individual coronary stenosis seemed to be lower in subjects who had premature termination of exercise due to early appearance of ST depression. Conclusion: These results suggest that the overall diagnostic sensitivity of Tc-99m MIBI myocardial perfusion SPECT is not significantly affected by the degree of exercise in stable patients undergoing symptom-limited treadmill exercise testing. Myocardial perfusion SPECT imaging should be added to routine exercise stress testing for the detection of coronary artery disease.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.464-471
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• 2016

To investigate the effects of cardiac rehabilitation (CR) on cardiopulmonary exercise capacity in both elderly and younger patients with myocardial infarction (MI). Of the MI patients who received hospital-based CR between February 2012 and December 2015, we retrospectively reviewed the medical records of patients who continued a follow-up through the outpatient clinic. A total of 46 patients (18 elderly patients (${\geq}60years$) and 28 younger patient (< 60)) were included in this study. The subjects visited the clinic to perform aerobic exercises with ECG monitoring based on their initial exercise tolerance test outcome. The exercise capacity was measured by symptom-limited exercise tests before and after hospital-based CR. Before CR, the elderly group had a significantly lower exercise capacity in peak VO2, METs, anaerobic threshold, exercise time, respiratory exchange ratio (RER) than the younger group. After CR, elderly groups showed a significantly improved exercise capacity in exercise time, HRmax, HRrest, peak VO2, METs, anaerobic threshold, and RER. Both elderly and younger groups showed similar improvement of cardiopulmonary exercise capacity after hospital-based CR. There is a very low cardiac rehabilitation participation and referral rates with MI patients in Korea. It is considered necessary to further expand the participation of cardiac rehabilitation in elderly MI patients.

• The Korean Journal of Physiology
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• v.16 no.2
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• pp.129-136
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• 1982

We studied this experiment to compare the effects of exercise and other body conditions: i.e., Flack test, cold pressor test and bicycle ergometry on the electrocardiogram. We had sixty healthy college students who were thirty nine men and twenty one women. Their $mean{\pm}SD$ values of physical characteristics were as follows: age; $22.0{\pm}1.4$, weight; men $61.7{\pm}5.6\;kg$, women $46.2{\pm}7.47\;kg$. We observed the changes of P-Q and Q-T interval, R and T amplitude, mean QRS vector, S-T segment deviation, and P and T vector. The result obtained were summarized as follows: P vector was shifted rightward regardless of the type of stress. T vector was shifted var-in each stress but in the bicycle ergometry T vector was shifted leftward. Mean QRS vector was shifted rightward immediately after the bicycle ergometry. Percentage of the occurrence of the depression of S-T segment was 21.7% at the immediately after the submaximal bicycle ergometry in lead II. The elevation of S-T segment was often observed after the mild stresses. Increased amplitude of T wave in the cold pressor test and decreased amplitude of T wave in the bicycle ergometry were observed. In the bicycle ergometry and other stresses, the precise mechanism of S-T segment changes was unexplained but insufficient repolarization in base or apex of the left ventricle due to heart strain was indicated by so called S-T vector analysis.

• Journal of Biomedical Engineering Research
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• v.40 no.1
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• pp.32-37
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• 2019

In this study, we designed a blending algorithm for rate adaptive pacing for cardiac pacemaker. Generally, rate adaptive pacing (RAP) is applied to patients whose heart rate does not rise during exercise for chronotropic incompetence (CI) patient. It is very important to develop an algorithm for RAP that can be properly applied to CI patients. In order to design an RAP algorithm we used dual sensors. Firstly, we designed a bio-signal measurement system based on the dual sensors, which are accelerometer and respiratory system. Secondly, we conducted treadmill test for the simulation experiment while using 3-lead ECG as reference. Finally, we designed a blending algorithm based on activation state of the dual sensors. The proposed blending algorithm was subdivided into three sections based on the accelerometer signal, which are rapidly increased section (W1), hardly changed section (W2), and decreased section (W3). Each weight is set aside for each section. To evaluate this algorithm, ten healthy adult males were participated. The correlation and Root Mean Square Error between the proposed algorithm and the reference were compared, and shown to be r=0.88 and 2.82 bpm, respectively. These results show that the proposed blending algorithm of dual sensors enables proper tracking of the heart rate during exercise. Also, it shows the possibility that the proposed blending algorithm can be applied to improve quality of life of the chronotropic incompetence patient.

• Fashion & Textile Research Journal
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• v.24 no.6
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• pp.694-706
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• 2022

This study focusses on the development of a motion-sensing smart leggings prototype with the help of a module that monitors motion using a fiber-type stretch sensor. Additionally, it acquires data on Electrocardiogram (ECG), respiration, and body temperature signals, for the development of smart clothing used in online exercise coaching and customized healthcare systems. The research process was conducted in the following order: 1) Fabrication of a fiber-type elastic strain sensor for motion monitoring, 2) Positioning and attaching the sensor, 3) Pattern development and three-dimensional (3D) design, 4) Prototyping 5) Wearability test, and 6) Expert evaluation. The 3D design method was used to develop an aesthetic design, and for sensing accurate signal acquisition functions, wearability tests, and expert evaluation. As a result, first, the selection or manufacturing of an appropriate sensor for the function is of utmost importance. Second, the selection and attachment method of a location that can maximize the function of the sensor without interfering with any activity should be studied. Third, the signal line selection and connection method should be considered, and fourth, the aesthetic design should be reflected along with functional verification. In addition, the selection of an appropriate material is important, and tests for washability and durability must be made. This study presented a manufacturing method to improve the functionality and design of smart clothing, through the process of developing a prototype of motion-sensing smart leggings.

• Tuberculosis and Respiratory Diseases
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• v.48 no.2
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• pp.203-209
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• 2000

Background: Exercise is a very common precipitant of asthma. Bronche-constriction associated with exercise can occur in 75~90% of individuals with asthma The estimated prevalence(30~85%) of gastroesophageal reflux(GER) in patients with asthma is significantly higher than in general population. We performed pH monitoring during the exercise in order to evaluate whether exercise induced asthma(EIA) could be related to GER and acid reflux-induced esophagobronchial reflex-mediated bronchospasm might be a factor for EIA. Method: Following an overnight fast, 18 patients with a suspected EIA(6 men, 12 women) were studied. Monitoring of intraesophageal pH, ECG and spirometry was done for 1 hour before treadmill exercise. After baseline monitoring, subjects underwent symptom-limited treadmill exercise with Bruce protocol and continuous monitoring for 60 min after exercise. Spirometry was done at baseline prior to exercise, and repeated every 10 min after full exercise for 60 min. Results: Exercise-induced bronchoconstriction was noted in 15 patients, who performed MBPT and 12 patients confirmed for bronchial asthma and 3 patients were diagnosed exercise-induced astham. Five of 15 EIA patients demonstrated a pathologic degree of GER. Conclusion: We suggest that GER may be one of pathophysiologic factors of EIA and evoke further concentration on the GER in the EIA patients.

• The Korean Journal of Nuclear Medicine
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• v.34 no.3
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• pp.199-206
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• 2000

Purpose: Myocardial perfusion scintigraphy is a useful technique to diagnose and to predict prognosis in patients with suspected or known coronary artery disease. The purpose of the present study is to evaluate the prognostic value of normal exercise $^{99m}Tc$-MIBI myocardial perfusion single photon emission computed tomography (SPECT) and to analyze results with regard to those of exercise electrocardiography or coronary angiography. Materials and Methods: We evaluated 301 patients (mean age $52{\pm}10$ years, 166 males and 135 females) with normal exercise $^{99m}Tc$-MIBI myocardial perfusion SPECT performed for suspected coronary artery disease. Subject were evaluated for cardiac events and followed for 8-55 months (mean $19{\pm}10$ months) after imaging. Results: During the follow-up period, there was no cardiac death but only one non-fatal myocardial infarction (event rate 0.21% per year). In addition, only one patient underwent coronary revascularization. There was no significant difference in cardiac event rate between patients with positive (n=27) and negative (n=235) exercise electrocardiography (p:NS). There was no cardiac event in 17 patients who underwent coronary angiography (4 patients with >50% luminal narrowing, 2 patients with vasospasm and 11 patients with no significant lesion). Conclusion: Patients with normal exercise $^{99m}Tc$-MIBI myocardial perfusion SPECT has a very low risk for cardiac events regardless of exercise electrocardiographic and coronary angiographic findings.

• The Korean Journal of Physiology
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• v.18 no.1
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• pp.67-79
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• 1984

In an effort to elucidate the physiological characteristics in cardiopulmonary function, electromyogram(EMG), and blood chemistry in athletic high school students, an analysis of electrocardiogram(ECG) and EMG, pulmonary function test, venous blood gas analysis($Pvo_2$ and$Pvco_2$), and measurement of heart rate, blood pressure, respiratory rate, blood glucose and blood lactate were made for 16 to 19 year-old high school students who were divided into athletic (n=19) and non-athletic (n=20) group. The results obtained are summarized as follows. 1) ECG intervals in athletes were longer than in non-athletes, and the difference was significant in R-R, Q-T and T-P intervals. Resting heart rate in athletes was 56.3/min showing a bradycardia compared with 79.8/min in non-athletes. Amplitudes of R and T waves in lead $V_5$ were significantly higher than in non-athletes. 2) Pulmonary function parameters in athletes showed higher values than in non-athletes. Parameters which showed significant differences were FEV 0.5, PEF, FEF 25%, PIF and FEF $200{\sim}1.200\;ml. 3) Heart rate, blood pressure, and respiratory rate after exercise were significantly elevated from resting values. Heart rate and respiratory rate showed greater increase in non-athletes, while blood pressure showed greater increase in athletes. 4) $Pvo_2$ was lowered ana $Pvco_2$ was elevated after exercise, and there was no significant difference between two groups. 5) Blood glucose and lactate levels were elevated after exercise. The difference was significant in blood lactate, and was greater in non-athletes. 6) EMG amplitude was steadily increased with increasing load of exercise, and the increase was greater in athletes than in non-athletes.

• Journal of Chest Surgery
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• v.12 no.3
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• pp.297-305
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• 1979

Occlusive coronary artery disease presents a potential threat to a significant population in the United States. According to many case reports, the increasing incidence of coronary artery disease due to atherosclerosis is noted in Korean, recently. Operative vascular procedures have increased steadily in number over the past 20 years in the United States. There have been many isolated case reports about coronary artery surgery, but these had little clinical impact. Nowadays, major three coronary bypass surgery has developed principally at three cardiac centers in the United States since 1967. Among three coronary bypass operation, the aorta-coronary artery saphenous vein bypass graft was first demonstrated by Favolaro and Effler at the Cleveland Clinic in 1967. We experienced one case of coronary artery disease, which was treated successfully by aorta-coronary saphenous vein graft with mild hypothermia under extracorporeal circulation in May, 1977. Saphenous vein was removed from above the knee and was 2.5 mm in diameter. The left ventricle was not vented for the left ventricle was not overdistended. Temporary artificial pace-maker-Medtronic-was implanted for the prevention and treatment of post-operative arrhythmia and heart block in post-operative first day. He is a 57 year old male businessman who had been suffered from hypertension [200 mmHg in systolic pressure] since 4 years ago, who had intermittent conservative treatment at local clinic. He had been afflicted with severe chest pain with choking sensation for 50 days. This symptom was aggravated exposing cold weather, or cold water, but was respond to rest. Pre-operative ECG revealed no any other ischemic sign except sinus bradycardia. Significant S-T segment depression was noted at lead II, AVF after double 5 minutes exercise, indicating positive Master`s test. Serum cholesterol was slight elevated to 253 mg/dl. Final pre-operative diagnosis was made by coronary arteriogram, which showed about 1.0-cm segmental 90 % occlusive atherosclerotic lesion in the proximal part of right coronary artery above the origin of acute marginal artery. Left coronary artery revealed good patency and there was no collateral circulation between right and left coronary artery .Hospital course was not eventful. He was discharged with good result on the post-operative day. He has been free from chest pain for longer than 2 years. And also the arterial flow in the coronary bypass graft is auscultated with the pocket-sized ultrasonic velocity detector, which shows the patency of the coronary bypass graft good.