• Korean Circulation Journal
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• 제53권9호
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• pp.621-631
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• 2023

Background and Objectives: The morphology-voltage-P-wave duration (MVP) electrocardiography (ECG) risk score is a newly defined scoring system that has recently been used for atrial fibrillation (AF) prediction. The aim of this study was to evaluate the ability of the MVP ECG risk score to predict AF in patients with an implantable cardioverter defibrillator (ICD) and heart failure with reduced ejection fraction in long-term follow-up. Methods: The study used a single-center, and retrospective design. The study included 328 patients who underwent ICD implantation in our hospital between January 2010 and April 2021, diagnosed with heart failure. The patients were divided into low, intermediate and high-risk categories according to the MVP ECG risk scores. The long-term development of atrial fibrillation was compared among these 3 groups. Results: The low-risk group included 191 patients, the intermediate-risk group 114 patients, and the high-risk group 23 patients. The long-term AF development rate was 12.0% in the low-risk group, 21.9% in the intermediate risk group, and 78.3% in the high-risk group. Patients in the high-risk group were found to have 5.2 times higher rates of long-term AF occurrence compared to low-risk group. Conclusions: The MVP ECG risk score, which is an inexpensive, simple and easily accessible tool, was found to be a significant predictor of the development of AF in the long-term follow-up of patients with an ICD with heart failure with reduced ejection fraction. This risk score may be used to identify patients who require close follow-up for development and management of AF.

• 대한물리치료과학회지
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• 제7권1호
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• pp.311-319
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• 2000

This study was to measure whether single axis foot or the SACH foot applied to below-knee amputation patients would bring positive changes to the patients' cardiopulmonary function, and help them to overcome their disability. The experiment took place at Asan Medical Center, University of Ulsan, from July 20th to November 20th, 1999 with 10 below-knee amputation patients. The patients were asked to equip single axis foot and SACH foot by turns and lead them to walk on a treadmill which was designed to increase its steep slope. Patients heart rate and blood pressure were recorded before and after their walking, The heart rate, systolic blood pressure, diastolic blood pressure of the patients who were equipped with, either SACH foot or single axis foot, have been increased with as the slant becoming steeper. The heart rates during the experiment did not show relevant changes according to the kind of foot used and the gradient, but the changes occurred before and after the walking(p=0.0001), The similar result of systolic blood pressure was found during the waking(p=0.01). Below-knee amputation patients are expected to walk and perform the routines better, no matter what type of foot is used, as long as they wear an artificial foot properly and taking features of foot product into consideration

• Journal of Chest Surgery
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• 제26권3호
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• pp.170-179
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• 1993

Three hundred consecutive adult patients having cardioaortic surgery under the cardiopulmonary bypass for a variety of cardioaortic lesions were evaluated retrospectively for postoperative hyperbilirubinemia[above 5mg/100ml].We found twenty eight patients with postoperative hyperbilirubinemia and divided them into two groups according to the postoperative day of peak s-bilirubin .Group A was the patients with a peak s-bilirubin level within three days ,and group B above three days postoperatively.Group B was divided into group S[survive] and group D[death] . We had compaired the survival & death group and observed the correlation between the decreasing tendency of postoperative s-bilirubin & the nutrition per os in group B. The incidence of postoperative hyperbilirubinemia,as defined by a s-bilirubin concentration of 5.0mg/100ml or greater,was 9.3%.The mortality rates of group A & B were 0.0% and 35.7% respectively.Important contributing factors between group A & B were the age,duration of ICU,Max.DOAB[maximum dose of catecholamine used],amount of blood transfused during or shortly after surgery and preoperative pulmonary hypertension[main pulmonary artery pressure > 30mmHg] and backward heart failure. The risking factors of group D compared to group S were as follows the age,preoperative & postoperative SGOT[serum glutamic-oxaloacetic trasaminase],postoperative total & indirect bilirubin,cardiopulmonary bypass time,duration of ICU & mechanical ventilation ,Max.DOAB,preoperative pulmonary hypertension and backward heart failure.The six patients in group B showed good correlation between the decreasing point of s-bilirubin and the starting day of oral or tube feeding.

• Journal of Biosystems Engineering
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• 제38권2호
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• pp.163-170
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• 2013

Purpose: The purpose of this study is to provide analysis of physiological, biomechanical responses occurring from the operation to lifting or twist lifting task appears frequently in agricultural work. Methods: This study investigated the changes of physiological factors such as heart rate, heart rate variability (HRV) and biomechanical factors such as physical activity and kinetic analysis in the task of twisting at the waist while lifting. Results: Heart rates changed significantly with the workload. The result indicated that the workload of 2 kg was light intensity work, and the workload of 12 kg was hard intensity work. Physical activity increased as the workload increased both on wrist and waist. Besides, stress index of the worker increased with the workload. Dynamic load to herniated discs was analyzed using inertial sensor, and the angular acceleration and torque increased with the workload. The proposed measurement system can measure the recipient's physiological and physical signals in real-time and analyzed 3-dimensionally according to the variety of work load. Conclusions: The system we propose will be a new method to measure agricultural workers' multi-dimensional signals and analyze various farming tasks.

• The Korean Journal of Physiology
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• 제10권1호
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• pp.49-54
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• 1976

The change of heart rates during Flack Test was observed in the pregnant women, $24{\sim}48$weeks, of gestational age, to analyze mechanical and neural regulatory factors in responses to the positive lung inflation. The results obtained were summarized as followings: 1) Endurance tine of Flack Test was 37.6 sec, in the nonpregnant women, and 25.1 sec. in the pregnant women. 2) When Flack Test was employed, heart rate was decreased in early stage of Flack Test in the pregnant women, while heart rate was increased in the nonpregnant women. 3) In the pregnant women bradycardia due to abdominal mechanical intervention in early stage of Flack Test was prominent, while tachycardia was found in the nonpregnant women. 4) During Flack Test, tachycardia due to sympathetic central reflex activation was observed immediately after bradycardia in early stage of Flack Test. 5) It may be noted that Flack Test employed in the present study is a useful model to evaluate and analyze the neural and mechanical abdominal intervention factor in response to the positive inflation of lung in pregnant women.

• 대한두개안면성형외과학회지
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• 제22권1호
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• pp.38-44
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• 2021

Background: The free flap surgical method is useful for the reconstruction of head and neck defects. This study retrospectively analyzed the results of head and neck reconstructions using various types of free flaps over the past 30 years. Methods: Between 1989 and 2018, a total of 866 free flap procedures were performed on 859 patients with head and neck defects, including 7 double free flaps. The causes of vascular crisis and salvage rate were analyzed, and the total flap survival rate calculated among these patients. Additionally, the survival and complication rates for each flap type were compared. Results: The 866 cases included 557 radial forearm flaps, 200 anterolateral thigh flaps, 39 fibular osteocutaneous flaps, and 70 of various other flaps. The incidence of the vascular crisis was 5.1%; its most common cause was venous thrombosis (52.3%). Salvage surgery was successful in 52.3% of patients, and the total flap survival rate was 97.6%. The success rate of the radial forearm flap was higher than of the anterolateral flap (p< 0.01), and the primary sites of malignancy were the tongue, tonsils, and hypopharynx, respectively. Conclusion: The free flap technique is the most reliable method for head and neck reconstruction; however, the radial forearm free flap showed the highest success rate (98.9%). In patients with malignancy, flap failure was more common in the anterolateral thigh (5.5%) and fibular (5.1%) flaps.

• 대한임베디드공학회논문지
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• 제18권6호
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• pp.277-283
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• 2023

Vital signals provide essential information regarding the health status of individuals, thereby contributing to health management and medical research. Present monitoring methods, such as ECGs (Electrocardiograms) and smartwatches, demand proximity and fixed postures, which limit their applicability. To address this, Non-contact vital signal measurement methods, such as CW (Continuous-Wave) radar, have emerged as a solution. However, unwanted signal components and a stepwise processing approach lead to errors and limitations in heart rate detection. To overcome these issues, this study introduces an integrated neural network approach that combines noise removal, demodulation, and dominant-frequency detection into a unified process. The neural network employed for signal processing in this research adopts a MLP (Multi-Layer Perceptron) architecture, which analyzes the in-phase and quadrature signals collected within a specified time window, using two distinct input layers. The training of the neural network utilizes CW radar signals and reference heart rates obtained from the ECG. In the experimental evaluation, networks trained on different datasets were compared, and their performance was assessed based on loss and frequency accuracy. The proposed methodology exhibits substantial potential for achieving precise vital signals through non-contact measurements, effectively mitigating the limitations of existing methodologies.

• Korean Circulation Journal
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• 제53권9호
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• pp.594-605
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• 2023

Acute myocardial infarction (AMI) is a major cause of morbidity and mortality in the Asia-Pacific region, and mortality rates differ between countries in the region. Systems of care have been shown to play a major role in determining AMI outcomes, and this review aims to highlight pre-hospital and in-hospital system deficiencies and suggest possible improvements to enhance quality of care, focusing on Korea, Japan, Singapore and Malaysia as representative countries. Time to first medical contact can be shortened by improving patient awareness of AMI symptoms and the need to activate emergency medical services (EMS), as well as by developing robust, well-coordinated and centralized EMS systems. Additionally, performing and transmitting pre-hospital electrocardiograms, algorithmically identifying patients with high risk AMI and developing hospital networks that appropriately divert such patients to percutaneous coronary intervention-capable hospitals have been shown to be beneficial. Within the hospital environment, developing and following clinical practice guidelines ensures that treatment plans can be standardised, whilst integrated care pathways can aid in coordinating care within the healthcare institution and can guide care even after discharge. Prescription of guideline directed medical therapy for secondary prevention and patient compliance to medications can be further optimised. Finally, the authors advocate for the establishment of more regional, national and international AMI registries for the formal collection of data to facilitate audit and clinical improvement.

• Korean Circulation Journal
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• 제53권1호
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• pp.34-46
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• 2023

Background and Objectives: Diabetes mellitus (DM)-associated heart failure (HF) causes high morbidity and mortality. In this study, we established a zebrafish larvae model for in vivo research on diabetic HF. Methods: DM-like phenotypes were induced by treating zebrafish larvae with a combination of D-glucose (GLU) and streptozotocin (STZ). HF was induced by treatment with terfenadine (TER), a potassium channel blocker. Additionally, myocardial contractility, motility, and viability were evaluated. Results: The zebrafish larvae treated with a combination of GLU and STZ showed significantly higher whole-body glucose concentrations, lower insulin levels, and higher phosphoenolpyruvate carboxykinase levels, which are markers of abnormal glucose homeostasis, than the group treated with only GLU, with no effect on viability. When treated with TER, DM zebrafish showed significantly less myocardial fractional shortening and more irregular contractions than the non-DM zebrafish. Furthermore, in DM-HF with reduced ejection fraction (rEF) zebrafish, a significant increase in the levels of natriuretic peptide B, a HF biomarker, markedly reduced motility, and reduced survival rates were observed. Conclusions: We established a DM-HFrEF zebrafish model by sequentially treating zebrafish larvae with GLU, STZ, and TER. Our findings indicate the potential utility of the developed zebrafish larvae model not only in screening studies of new drug candidates for DM-HFrEF but also in mechanistic studies to understand the pathophysiology of DM-HFrEF.

• 응용통계연구
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• 제11권1호
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• pp.163-175
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• 1998

위험률 변화점모형에서 특별한 함수형이나 분포함수에 대한 가정을 하지 않는 일반적인 모형을 고려하였다. 이러한 모형은 지금까지 주로 다루어 왔던 상수항 위험률의 변화점모형뿐만 아니라 여러 유형의 변화점모형을 내포한다. 중도절단된 자료하에서 위험률 변화점에 관한 모수적 모형을 가정하지 않고 변화점 이전과 이후의 넬슨(Nelson) 누적위험함수 추정량의 기울기 차를 이용하여 추정량을 제안하고, 그의 점근적 성질을 규명한다. 붓스트랩 추정량의 일치성과 점근분포를 유도하고, 몇가지 분포함수의 경우에 몬테칼로 모의실험을 통해 제안된 방법의 경험적 성질을 살펴보았다. 또한, 심장병 이석환자의 생존시간 자료를 통해 변화점을 추정하고 추정량의 붓스트랩 분포를 구하였다.