동기능부전 환자에서 방실전도계의 전기생리학적 특성에 관한 연구

박형욱(Hyung Wook Park),김준우(Joon Woo Kim),김성희(Seong Hee Kim),조장현(Jang Hyun Cho),안영근(Young Keun Ahn),박주형(Joo Hyung Park),정명호(Myung Ho Jeong),조정관(Jeong Gwan Cho),박종춘(Jong Chun Park),강정채(Jung Chaee Kang) 대한내과학회 1998 대한내과학회지 Vol.55 No.3

N/A Background: It is very important to evalute the function of the atrioventricular conduction system in selecting appropriate pacemaker, pacing and sensing mode in sick sinus syndrome. It has been reported that atrioventricular conduction abnormalities were commonly accompanied with sinus node dysfunction (SND). However, there were several long term follow-up studies indicating that incidence of AV conduction abnormalities was as low as below 1% a year in patients with SND implanted pacemaker. This study was performed to evaluate the properties of the AV conduction system in patients with SND. Subjects and Methods: Patients subjected to this study were fifty-eight who underwent electrophysiologic study on suspicion of SND. Sinus node recovery time (SNRT) was defined as the longest time among the times that sinus rhythm reappeared after rapid atrial pacing for 45 seconds with several cycle lengths, and corrected SNRT (cSNRT) was worked out by subtracting sinus cycle length (SCL) from SNRT. Criteria for sinus node dysfunction were 1550 msec or more on SNRT, 550 msec or more on cSNRT and group A (23 cases, 58±13 yrs) was defined as SND not retrieved to normal after intravenous administration of atropine 1-2 mg, group B (21 cases, 52±14 yrs) was retrieved to normal and group C (14 cases, 54±13 yrs) was normal control group. Abnormalities of the AV conduction system were defined as 150 msec or more on AH interval, 500 msec or more on AVblock cycle length (AV-BCL), 4% msec or more on AV nodeeffective refractory period (AVN-ERP). Results: SCI. in group A, B, C was 1197±340 msec, 1215±273 msec, and 898±129 msec, respectively at baseline and 886±218 msec, 798±106 msec, and 722±110 msec respectively after atropine administration, showing a significant prolongation of SCL in group A and B at baseline (p<0.001) and group A after atropine administration (p<0.05). SNRT in group A, B, C was 3520±1817 msec, 3180±2390 msec, and 1282±116, respectively at baseline and 4155±4281 msec, 1237±210 msec, 1020±245 msec, respectively after atropine administration, showing a significant prolongation of SNRT in group A and B at baseline (p<0.001) and group A after atropine administration (p<0.05). AH intervals at baseline and after atropine administration were 107±27 msec and 100±20 msec in group A, 101±21 and 91±14 in group B, and 118±32 and 83±23 in group C, showing no significant difference between 3 groups. AV-BCLs at baseline and after atropine administration were 428±151 msec and 453±301 msec in group A, 525±140 and 370±53 in group B, and 461±120 361±94 in group C, showing no significant difference between 3 groups. AVN-ERP was 315±57 msec in group A, 343±132 msec in group B, 347±132 in group C, showing no significant difference between 3 groups. There was no significant difference in the incidences of cases with abnormal AH interval, AV-BCI AVN-ERP, HV interval between 3 groups. AV block greater than second degree was observed in one patient of group A but none of group B and C. Conclusions: Atrioventricular conduction abnormalities in patients with sinus node dysfunction were not mare common than control subjects, Therefore, atrial pacing rather than ventricular or dual chamber pacing may be safely selected as a permanent pacing mode for sick sinus syndrome with no combined significant AV block.

Matrix 27 요소 기반 회전 유니트 정/동강성 예측 연구

김현명(Hyun Myung Kim),박형욱(Hyung Wook Park) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.6

대동맥 탄성도와 동맥경화증의 혈액학적 인자의 관계

김현국 ( Hyun Kuk Kim ),박종춘 ( Jong Chun Park ),김성수 ( Sung Soo Kim ),최홍상 ( Hong Sang Choi ),심두선 ( Doo Sun Sim ),윤남식 ( Nam Sik Yoon ),윤현주 ( Hyun Ju Yoon ),홍영준 ( Young Joon Hong ),박형욱 ( Hyung Wook Park ),김주 대한내과학회 2009 대한내과학회지 Vol.77 No.1

Background/Aims: The elasticity of the aorta modulates the entire cardiovascular system. Increasing arterial stiffness with the loss of aortic elasticity is not only a surrogate marker for early atherosclerosis, but also a predictor of cardiovascular events. Methods: This study included 203 patients (57.6±14.7 years, 117 male) who underwent diagnostic transesophageal echocardiography. We investigated the correlation between the arterial stiffness index (β stiffness index), which is calculated from the distensibility of the descending thoracic aorta and blood pressure, and known serologic markers of atherosclerosis and cardiovascular events. Results: The β stiffness index correlated significantly with the brachial-ankle pulse wave velocity (R2=0.243, p<0.001) and in-tima-media thickness of the descending thoracic aorta (R2=0.470, p<0.001). It also correlated with age (r=0.465, p<0.001) and the presence of diabetes mellitus (r=0.250, p<0.001). The β stiffness index was significantly positively correlated with the levels of N-terminal pro-brain natriuretic peptide (NT-proBNP), high-sensitivity C-reactive protein (hsCRP), glucose, HbA1c, apolipoprotein (Apo) A-I, and erythrocyte sediment rate. A multivariate regression analysis demonstrated that the β stiffness index was associated with the levels of NT-proBNP, hsCRP, HbA1c, and Apo A-I. Conclusions: The β stiffness index for the distensibility of the descending thoracic aorta significantly correlates with other parameters of arterial stiffness and serologic markers for atherosclerosis. Therefore, the β stiffness index can be used as a parameter of cardiovascular events in diseases requiring transesophageal echocardiography, such as atrial fibrillation and mitral stenosis. (Korean J Med 77:68-75, 2009)

고밀도 전자빔 드릴링 기반 다중 홀 메탈 필터의 대면적 전자빔 하이브리드 디버링 연구

박현민(Hyun min Park),박형욱(Hyung wook Park) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.6

급성 심근경색증 환자의 입원 중 합병증과 1년간 임상경과의 예측인자

윤현주 ( Hyun Ju Yoon ),정명호 ( Myung Ho Jeong ),김계훈 ( Kye Hun Kim ),박근호 ( Keun Ho Park ),심두선 ( Doo Sun Sim ),박형욱 ( Hyun Wook Park ),윤남식 ( Nam Sik Yoon ),홍영준 ( Young Joon Hong ),김주한 ( Ju Han Kim ),안영근 ( Yo 대한내과학회 2009 대한내과학회지 Vol.77 No.6

Background/Aims: This study evaluated the predictors of in-hospital early complications and 1-year clinical events in patients with acute myocardial infarction (AMI). Methods: A total of 1,000 consecutive patients (63.4±12 years, 705 males) with AMI were divided into two groups according to the presence of in-hospital events (IHE): group I had IHEs (n=175, 65.6±12 years, 115 males), and group II had no events (n=825, 62.8±12 years, 590 males). IHE included death, cardiogenic shock, pacemaker implantation, ventricular arrhythmia, and mechanical ventilation. Results: The levels of glucose, creatinine, maximal creatine kinase (CK), troponin-I, hs-CRP, and NT-proBNP were higher in group I than in group II. Increased left ventricular dimension, a low ejection fraction, mitral regurgitation (MR), diastolic dysfunction, and a high wall motion score index were more common in group I compared with group II. The initial Killip class, ST-elevation AMI, and high levels of glucose, creatinine, CK-MB, troponin I, hs-CRP, NT-proBNP, and MR were significant independent predictors of IHE on multivariate analysis. During the 1-year follow-up, the major adverse cardiac event (MACE) rate was higher in group I than in group II. IHE, especially cardiopulmonary resuscitation, cardiogenic shock, and respiratory failure, were independent predictors of MACE during the 1-year clinical follow-up. Conclusions: High levels of glucose, creatinine, CK-MB, troponin I, hs-CRP, NT-proBNP, and MR were predictors of IHE, and the 1-year MACE-free survival was lower in AMI patients with IHE. (Korean J Med 77:723-733, 2009)

공작기계 베어링 결합부의 전산 모델링

김현명(Hyun Myung Kim),서재우(Jae Wu Seo),박형욱(Hyung Wook Park) Korean Society for Precision Engineering 2012 한국정밀공학회지 Vol.29 No.10

The bearing coupling section of machine tools is the most important factor to determine their static/dynamic stiffness. To ensure the proper performance of machine tools, the static/dynamic stiffness of the rotating system has to be predicted on the design stage. Various parameters of the bearing coupling section, such as the spring element, node number and preload influence the characteristics of rotating systems. This study focuses on the prediction of the static and dynamic stiffness of the rotating system with the bearing coupling section using the finite element (FE) model. MATRIX 27 in ANSYS has been adopted to describe the bearing coupling section of machine tools because the MATRIX 27 can describe the bearing coupling section close to the real object and is applicable to various machine tools. The FE model of the bearing couple section which has the sixteen node using MATRIX 27 was constructed. Comparisons between finite element method (FEM) predictions and experimental results were performed in terms of the static and dynamic stiffness.

조선소 근로자들의 폐쇄성 폐기능 저하와 관련된 요인

김자현 ( Ja Hyun Kim ),김영욱 ( Young Wook Kim ),채창호 ( Chang Ho Chae ),손준석 ( Jun Seok Son ),김찬우 ( Chan Woo Kim ),이준호 ( Jun Ho Lee ),박형욱 ( Hyung Wook Park ),조병만 ( Byung Mann Cho ) 한국산업보건학회 2015 한국산업보건학회지 Vol.25 No.4

Objectives: Alongside smoking, occupational exposure is an important risk factor for chronic obstructive pulmonary disease. The purpose of this study was to evaluate factors associated with occupational pulmonary function decline that can be used to create guidelines for the health management of shipyard workers Materials: This study analyzed spirometry from 10,597 male shipbuilding workers. Functional decline in spirometry was defined as FEV1/FVC <70% and logistic regression for work duration and occupational hazard exposure was performed Results: Among the subjects, 4.2% showed an obstructive pattern in pulmonary function. The odds ratios for hazard exposure were 1.67(indirect) and 3.54(direct), and for work duration 1.97(10-18 years), 2.29(19-27), and 5.02(28+). After adjusting for smoking and work-related factors, the odds ratios for work durations of over 10 years were 1.73(10-18 years), 1.99(19-27), and 4.09(28+), but for hazards exposure was 1.71(direct) alone after adjustment. Conclusions: Occupational COPD is insidious and chronic, and thus long-term hazard exposed(especially over 10 years) shipyard workers with functional decline in spirometry need to prevent and manage COPD. This study is important for establishing guidelines to manage hazard exposure among shipyard workers and prevent COPD

우측 방실우회로의 전극도자 절제에 효과적인 접근방법에 대한 연구

조정관(Jeong Gwan Cho),박우석(Woo Suck Park),배열(Youl Bae),안영근(Young Keun Ahn),류제영(Jay Young Rhew),김남호(Nam Ho Kim),이상현(Sang Hyun Lee),박형욱(Hyung Wook Park),박주형(Joo Hyung Park),정명호(Myung Ho Jeong),박종춘(Jong Chu 대한내과학회 1998 대한내과학회지 Vol.55 No.3

N/A Background: Although radiofrequency catheter ablation (CA) of the accessory pathway (AP) is very effective and safe, it has been reported that CA is more difficult in the right-side AP than the left-side AP, requiring the refinement of the conventional CA technique for the right-side AP. This study was, therefore, aimed to develop an effective technique for CA of the right-side AP. Methods: Fifty right-side APs in 45 patients which underwent CA were included in this study. The locations of APs were divided into 8 regions (anteroseptal, mid septal, posteroseptal, posterior, posterolateral, lateral, anterolateral, and anterior). After localizing APs, CA of the APs was attempted via the inferior vena cava (1VC) in all patients. If CA attempt via the IVC for more than 1 hour was failed, then CA was tried via the superior vena cava (SVC). Successful CA was defined as permanent loss of AP conduction even during infusion of isoproterenol (1-4 ㎍/min). The ways of approaching the ablation catheter to the successful target sites were classified into over-the-tricuspid valve approach (OV) via the IVC (IVC-OV), OV via the SVC (SVC-OV), under-the-tricuspid valve (UV) approach via the IVC (IVC-UV), and UV via the SVC (SVC-UV) and evaluated according to the AP locations. Results - The locations of the APs were anteroseptal in 5 APs, mid septal in 6, posteroseptal in 12, posterior in 3, posterolateral in 5, right lateral in 11, anterolateral in 4, and anterior in 4. Forty-eight (96.0%) of 50 APs were successfully ablated; 35 (70.0%) with primary 1VC approaches and 13 (26.0%) with secondat7 SVC approaches. As a successful approach, IVC-OV was 26 (54.2%); IVC UV, 9 (18.8%); SVC OV, 4 (8.3%), and SVC UV, 9 (18.8%). Secondary SVC approaches were required 7 (70.0%) in the lateral APs, 2 (50.0%) in the anterolateral Aps, 1 (25.0%) of the posterolateral APs, 1 (25.0%) in the anterior APs, 1 (20.0%) of the anteroseptal APs, and 1 (8.3%) in the posteroseptal APs but none in the midseptal and posterior APs. SVC-UV approach was used in 9 (69.2%) in 13 APs which were ablated with SVC approach. Conclusions: The ways of approach to successful target site in CA of the right-side APs are different according to the location and SVC approaches are frequently required in ablation of the lateral or anterolateral APs. Therefore, SVC approaches should be considered in these locations if the initial 1VC approaches are not successful.

다축 산업용 로봇기반 공정 시스템의 가상 물리 모델링 연구

김동찬(Dong Chan Kim),문창현(Chang Hyun Mun),이지현(Ji Hyun Lee),Simon S. Park,박형욱(Hyung Wook Park) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.4

두부규격 방사선 사진을 이용한 미소 시의 중안면부 연조직의 변화량 측정

천강용,신동환,전원배,김수호,김유진,박형욱,조진용,윤준용,서미현,이원덕,서제덕,이호,Cheon, Kang-Yong,Shin, Dong-Whan,Chun, Won-Bae,Kim, Soo-Ho,Kim, Eu-Gene,Park, Hyong-Wook,Cho, Jin-Yong,Yun, Jun-Yong,Seo, Mi-Hyun,Lee, Won-Deok,Suh, Je-D 대한악안면성형재건외과학회 2012 Maxillofacial Plastic Reconstructive Surgery Vol.34 No.6

Purpose: The aim of this study is to compare the soft tissue changes of the midfacial area at the repose position and the natural smiling position for the improvement of evaluation and planning in the orthognathic surgery. Methods: The total of 30 subjects, 15 male and 15 female, were included in this study. The metal point landmarks were placed at the cheek, orbital rim, subpupil, and nasal base. The movements of the landmarks were evaluated at the repose position and smiling position in the lateral and posteroanterior cephalograms. Paired t test and correlation analysis were used for the evaluation of the soft tissue changes statistically. Results: In the lateral cephalograms, the cheek point (4.49 mm in female, 4.87 mm in male) showed the most distant movement. All points presented significant movements, except the orbital rim and nasal base point in male. Cheek point presented significant positive correlation between the horizontal and vertical change in male. Subpupil point presented significant positive correlation between horizontal and vertical change in both male and female. In the posteroanterior cephalograms, the nasal base point (5.41 mm in female, 6.30 mm in male) showed the most distant movement. Subpupil point and nasal base point presented significant movements in both female and male. Nasal base point presented significant negative correlation between the horizontal and vertical change in both male and female. In the lateral and posteroanterior cephalograms, the positional changes of all points presented significant positive correlation with each other in both female and male. Conclusion: The cheek point in the sagittal view and the nasal base point in the frontal view showed the most distant movement on smile. In the sagittal view, the subpupil point and cheek point moved anteriorsuperiorly on smile. In the frontal view, the nasal base points moved laterosuperiorly on smile. In both the sagittal and frontal view, the positional changes of all point were highly correlated to each other. These results may be used in the soft tissue references for the treatment planning of the dentofacial deformity patients.