Lee, Chee-Hoon;Ju, Min Ho;Kim, Joon Bum;Chung, Cheol Hyun;Jung, Sung Ho;Choo, Suk Jung;Lee, Jae Won
Journal of Chest Surgery
/
v.47
no.3
/
pp.233-239
/
2014
Background: As hypertrophied myocardium predisposes the patient to decreased tolerance to ischemia and increased reperfusion injury, myocardial protection is of utmost importance in patients undergoing aortic valve replacement (AVR) for severe aortic valve stenosis (AS). Methods: Consecutive 314 patients (mean age, $62.5{\pm}10.8$ years; 143 females) with severe AS undergoing isolated AVR were included. Postoperative myocardial injury (PMI) was defined as 1) maximum postoperative creatinine kinase isoenzyme MB or troponin-I levels ${\geq}10$ times of reference, 2) postoperative low cardiac output syndrome or episodes of ventricular arrhythmia, or 3) left ventricular ejection fraction of less than 55% and decrease in left ventricle (LV) ejection fraction of more than 20% of the baseline value. Results: There were 90 patients (28.7%) who developed PMI. There were five cases of early death (1.6%), all of whom had PMI. On multivariable analysis, the use of histidine-tryptophan-ketoglutarate (HTK) solution instead of blood cardioplegia (odds ratio [OR], 3.06; 95% confidence interval [CI], 1.63 to 5.77; p=0.001), greater LV mass (OR, 1.04; 95% CI, 1.01 to 1.07; p=0.007), and increased cardiac ischemic time (OR, 1.13; 95% CI, 1.05 to 1.22; p<0.001) were independent predictors for PMI. Patients who had PMI showed significantly inferior long-term survival than those without PMI (p=0.049). Conclusion: PMI occurred in a considerable proportion of patients undergoing AVR for severe AS and was associated with poor long-term survival. HTK cardioplegia, higher LV mass, and longer cardiac ischemic duration were suggested as predictors of myocardial injury.
Soo Jung Park;Deok Heon Lee;Youngok Lee;Hanna Jung;Yongkeun Cho
Journal of Chest Surgery
/
v.56
no.6
/
pp.414-419
/
2023
Background: The recurrence of ventricular arrhythmias (VAs) in patients who have already undergone treatment with antiarrhythmic medication, catheter ablation, and the insertion of implantable cardioverter defibrillators is not uncommon. Recent studies have shown that bilateral cardiac sympathetic denervation (BCSD) effectively treats VAs. However, only a limited number of studies have confirmed the safety of BCSD as a viable therapeutic option for VAs. Methods: This single-center study included 10 patients, who had a median age of 54 years (interquartile range [IQR], 45-65 years) and a median ejection fraction of 58.5% (IQR, 56.2%-60.8%), with VAs who underwent video-assisted BCSD. BCSD was executed as a single-stage surgery for 8 patients, while the remaining 2 patients initially underwent left cardiac sympathetic denervation followed by right cardiac sympathetic denervation. We evaluated postoperative complications, the duration of hospital stays, and VA-related symptoms before and after surgery. Results: The median hospital stay after surgery was 2 days (IQR, 2-3 days). The median surgical time for BCSD was 113 minutes (IQR, 104-126 minutes). No significant complications occurred during hospitalization or after discharge. During the median follow-up period of 13.5 months (IQR, 10.5-28.0 months) from surgery, no VA-related symptoms were observed in 70% of patients. Conclusion: The benefits of a short postoperative hospitalization and negligible complications make BCSD a safe, alternative therapeutic option for patients suffering from refractory VAs.
Background: The durability of the tissue valve is important in choice between a mechanical valve and a tissue valve in cardiac surgery. We studied the mid-term results of tissue valve in the aortic position. Material and Method: The subjects were 380 patients who had undergone aortic prosthesis replacement between May 1990 and March 2009. We retrospectively analyzed hospital and outpatient records: the mean age was $69{\pm}9$ years; the male to female ratio was 227 : 162; and the mean follow-up duration was $46.7{\pm}40.8$ months (range 0~196 months). Result: 389 surgical cases in total had been taken with 380 patients. Early death occurred in 15 patients (3.9%). Overall survival rate at 1, 5 and 10 years were 92.3%, 78.1% and 54.2% respectively. Freedom from reoperation at 1, 5 and 10 years were 98.4%, 97.1% and 91.7% respectively. Freedom from structural valvular deterioration at 1, 5 and 10 years were 96.1%, 92.3% and 88.0% respectively. In the multivariate analysis of preoperative risk factors, young age (p<0.001) was significant risk factor for reoperation. High peak velocity in the postoperative period (p=0.034) and young age (p=0.029) were significant risk factors for structural valvular deterioration. Old age (p=0.001), long bypass time (p=0.035), concomitant coronary artery bypass graft surgery (p=0.003) and preoperative low left ventricular ejection fraction (p=0.003) were significant factors for early mortality. Preoperative estimated glomerular filtration rate (< 60 mL/min) (p=0.025) and persistent left ventricular hypertrophy (p=0.032) were the risk factors for late mortality. Conclusion: This study showed that the freedom from reoperation and the freedom from structural valvular deterioration in aortic tissue valve replacement were acceptable. It will be necessary to conduct further studies with long-term follow-up and more patients.
Kim, Soo-Hyun;Jung, Tae-Eun;Hong, Geu-Ru;Han, Sung-Sae
Journal of Chest Surgery
/
v.40
no.5
s.274
/
pp.329-340
/
2007
Background: Matrix Metalloproteinase (MMP) inhibition has emerged as a potential therapeutic strategy for the left ventricular dilatation that occurs after myocardial infarction. This study is designed to evaluate which treatment is better for attenuating the left ventricular remodeling via MMP inhibition 1) during the early, short highly MMP producing period of the initial phase or 2) during most of the period of the initial phase after myocardial infarction. Material and Method: Myocardial infarction was induced by ligation of the left anterior descending coronary artery in rabbits. The experimental group was divided into 3 groups. The myocardial infarction only (MI only) group consisted of 7 cases. The MMP inhibitor administered for 5 days after MI (MMPI 50) group had 6 cases, and these rabbits were given MMP inhibitor for 5 days after myocardial infarction, beginning with the postoperative first day. MMP inhibitor administered for 9 days (MMPI 90) group consisted of 5 cases and these rabbits were given MMPI for 9 days the same manner as above. CG2300 was used as a selective MMPI; this is a potent MMP-2 and -9 inhibitor Two-D echocardiograms were performed on all the groups at the time of preoperative period, the post-operative 1st week, the postoperative 20 week and the postoperative 30 week, and we measured the end-diastolic dimension (EDD), the end-systolic dimension (ESD), and the ejection fraction (EF). Result: The echocardiograms generally showed postoperative left ventricular dilatation in the MI only group. The EDD was increased significantly higher in the postoperative 1 week compared to the preoperative value (p<0.05). The ESD was also increased significantly higher in the postoperative 1st week, the postoperative 20 week and the postoperative 30 week compared to the preoperative value (p<0.05). Left ventricular dilatation was noted to be less In the MMPI 9d group than in the MI only and MMPI 5d groups. In the MMPI 9d group, there was no significant change of EF postoperatively compared to the preoperative period. MMP-2 and MMP-9 were measured from the infarcted myocardial tissue at post-MI 4 weeks by performing western blotting and zymography. The changes the of protein expression and activity of MMP-2 and MMP-9 were not significant in the three MI groups and the normal heart group. Histopathologic examination revealed severe collagen deposition in the MI only group. Collagen accumulation was reduced in both the MMPI groups. The MMPI 9d group revealed an increased number of capillaries. Conclusion: Left ventricular dilatation developed rapidly after, MI from ligation of the coronary artery and MMPI attenuated the ventricular dilatation. The effect of MMPI seemed to have better a result from its usage during most of the period of the initial phase after myocardial infarction. This suggested that increased neovascularization by MMPI may also contribute to attenuation of the left ventricular remodeling.
Park, Chul;Choi, Chi-bong;Kim, Il-hwan;Park, Hee-myung
Korean Journal of Veterinary Research
/
v.43
no.2
/
pp.307-310
/
2003
An atrial septal defect (ASD) is congenital heart disease with a communication between the atria, which allows blood to shoot from the atrium with pressure. A 3-month-old female Miniature Schunauzer was referred to the Veterinary Teaching Hospital of Konkuk University for the evaluation of systolic heart murmur. At presentation, the mucous membrane was cyanotic. On physical examination, an ejection-type systolic murmur was auscultated at the pulmonic area. In addition, thoracic radiography showed enlargement of main pulmonary artery and right atrial/ventricular enlargement. Echocardiography revealed dilated right atrium and atrial septal defect. However, mitral and tricuspid valve were still intact and well tolerating. The presence of an ASD was confirmed by identifying flow across the defect with color Doppler imaging. Doppler echocardiography provides a means of non-invasive documentation and quantification of ASD. Complete blood count and serum chemistry were not remarkable. Although large defect was confirmed between the two atrium, the patient did not show any obvious clinical signs of heart failure at this time.
Surgical treatment of partial endocardial cushion defect was accomplished in Feb. 1984 in this department. The 5 year old male patient had history of frequent upper respiratory tract infection and since his age of 3 years dyspnea on exertion and palpitation were noted but there were no cyanosis and clubbing. A thrill was palpable on the apex and grade IV/IV harsh systolic ejection murmur and diastolic murmur was audible on it. Liver was palpable about 3 finger breadths and no ascites. Chest X-ray revealed increased pulmonary vascularity, moderate cardiomegaly [C-T ratio; 0.69], and enlarged left atrium. EKG showed first degree heart block, RVH, LVH, and LAD. Echocardiogram showed paradoxical ventricular septal movement and abnormal diastolic movement of the anterior leaflet of mitral valve. Right heart catheterization resulted left to right shunt [Qp:Qs:2.1:1 ] and moderate pulmonary hypertension [60/40 mmHg]. Left ventriculogram showed mitral regurgitation [Grade III/IV] and filling of left atrium and right atrium nearly same time. Operative findings were: 1.Primum type atrial septal defect [3x2 cm] 2.Cleft on the anterior leaflet of mitral valve. 3.No interventricular communication and cleft of tricuspid valve leaflet. The mitral cleft was repaired with 4 interrupted sutures. The primum type atrial septal defect was closed with Dacron patch intermittently at endocardial cushion and continuously remainder. The post operative course was uneventful and discharged on 22nd postoperative day in good general conditions.
Valvular heart disease is one of the main current of cardiac problems and has many problems must be solved by sequelae and complications, etc. Rheumatic Mitral Stenosis is mainly attacked by rheumatic fever and developed by process of treatment of mitral valve or formation of trace. The purpose of this study is to examine the efficacy of oriental treatment for Cerebral Infarction with Rheumatic Mitral Stenosis. At the time of visiting ER, he was shown the symptoms of dull mentality, Rt. hemiplegia, global aphasia, dysphagia, chest discomfort, insomnia, dyspnea, etc, It showed that Atrial fibrillation in EKG monitoring, Atrial fibrillation, Rheumatic Mitral Stenosis, Ejection-Fraction slope 60% in Cardiac echography, Lt. atrial hypertrophy, Rt. atrial hypertrophy, Rt. ventricular hypertrophy with pulmonary congestion in chest X-ray. From the view of oriental diagnostic criteria. We classified the patient's clinical conditions and treated accordingly. As a result of treatment, symptoms were markedly improved and he was discharged. Further elaboration of oriental diagnostic classification could possibly lead to the fundamental treatment.
Background: The regression of the left ventricular hypertrophy after prosthetic valve replacement in patients with aortic valvular stenosis is an important factor to determine the appropriateness of the replaced prosthetic valvular size. Methods: To assess the regression of myocardial hypertrophy, a retrospective analysis of Doppler echocardiographic and electrocardiographic data was undertaken before, soon after(7.5$\pm$2.1 day), and late after(10.7$\pm$1.8 months) surgery in 36 patients(22 males, 14 female, mean age 54$\pm$12.1 years, mean BSA 1.61$\pm$0.15m2) with predominant aortic valvular stenosis. The patients underwent St. Jude Medical aortic valve replacement. By the size of the valves used, the patients were divided into three groups(19, 21 and 23+). Results: The mean body surface area(1.48$\pm$0.13) in the patients with the 19 mm valve was smaller than that in the other groups(1.63$\pm$0.12)(p<0.05). No significant changes of ejection fraction were detected in all groups over time. Left ventricular muscle mass index(gm/m2) was reduced significantly in the 21 and 23+ groups over time(p<0.05), but there were no significant changes in the 19 mm valve group. The electric voltage height on EKG at the period of late after surgery was reduced significantly in all groups(p<0.05). Conclusion: Despite clinical improvement, the LVH was not reduced significantly in 19 mm valve group. Thus we suggest that more attention and additional procedures such as annular enlargement should be taken in patients who will undergo the replacement of 19 mm prosthetic valve.
Background: Left ventricular dysfunction is one of the important prognostic factors of early mortality and long-term survival after valve operation. We studied the intermediate term results of mitral valve reconstruction in patients with moderate to severe left ventricular dysfunction. Material and Method: Forty four patients who underwent mitral valve reconstruction with a left ventricular ejection fraction (EF) of <45% or less (20∼45%) from April 1995 through July 2001 were reviewed retrospectively. Ages ranged from 10 to 67 years (46∼14 years) and 32 patients were in NYHA class III-IV. The mitral valve diseases were regurgitation (MR) in 28 patients, stenosis(MS) in 10, and mixed lesion in 5. The etiologies of mitral valve disease were rheumatic in 20 patients, degenerative in 14, ischemic in 5, annular dilatation in 2, congenital in 2, and endocarditis in 1. Operatively, all patients had annuloplasty and/or various valvuloplasty techniques, and a total of 52 procedures were concomitantly performed. Total cardiopulmonary bypass and aortic crossclamp time were 160$\pm$57 minutes and 112$\pm$45 minutes respectively. Result: Two operative deaths occurred as a result of left ventricular failure (4.5%). After the mean follow-up of 39 months (range, 10∼83 months), there was no late death. Transthoracic echocardiography revealed no or grade I of MR in 29 patients (72.5%) and no or mild MS in 35 patients (87.5%). The actuarial survival at 5 years was 100%. Four patients required mitral valve replacement due to progressive mitral valvular disease. The actuarial freedom from valve-related reoperation at 5 years was 84$\pm$9%. Conclusion: This study suggests that mitral valve reconstruction in patients with moderate to severe left ventricular dysfunction offers good early and intermediate survival and acceptable freedom from valve-related reoperation, and it is the strategy for effective management for these patients.
Park, Jeong-Hyun;Im, Hee-Kyung;Kim, Jee-Hee;Lee, Young-Il
The Korean Journal of Emergency Medical Services
/
v.20
no.2
/
pp.7-19
/
2016
Purpose: To investigate the effect of early hypothermia on post-resuscitation myocardial recovery and survival time after cardiac arrest and resuscitation in a rat model of myocardial infarction(MI). Methods: Thoracotomies were performed in 10 male Sprague Dawley rats weighing 450-455g. Myocardial infarction was induced by ligation of the left anterior descending coronary artery. Ninety minutes after arterial ligation, ventricular fibrillation was induced, cardiopulmonary resuscitation was subsequently performed before defibrillation was attempted. Animals were randomized to control group and experimental group(acute MI-normothermia)($32^{\circ}C$ for 4 hours). Duration of survival was recorded. Myocardial functions, including cardiac output, left ventricular ejection fraction, and myocardial performance index were measured using echocardiography. Results: Myocardial function was significantly better in hypothermia group than the control group during the first 4 hours post-resuscitation. The survival time of the experimental group was greater than that of the control group(p<.050). Conclusion: This study suggests that early hypothermia can attenuate post-resuscitation myocardial dysfunction after acute myocardial function, and may be a useful strategy in post-resuscitation care.
본 웹사이트에 게시된 이메일 주소가 전자우편 수집 프로그램이나
그 밖의 기술적 장치를 이용하여 무단으로 수집되는 것을 거부하며,
이를 위반시 정보통신망법에 의해 형사 처벌됨을 유념하시기 바랍니다.
[게시일 2004년 10월 1일]
이용약관
제 1 장 총칙
제 1 조 (목적)
이 이용약관은 KoreaScience 홈페이지(이하 “당 사이트”)에서 제공하는 인터넷 서비스(이하 '서비스')의 가입조건 및 이용에 관한 제반 사항과 기타 필요한 사항을 구체적으로 규정함을 목적으로 합니다.
제 2 조 (용어의 정의)
① "이용자"라 함은 당 사이트에 접속하여 이 약관에 따라 당 사이트가 제공하는 서비스를 받는 회원 및 비회원을
말합니다.
② "회원"이라 함은 서비스를 이용하기 위하여 당 사이트에 개인정보를 제공하여 아이디(ID)와 비밀번호를 부여
받은 자를 말합니다.
③ "회원 아이디(ID)"라 함은 회원의 식별 및 서비스 이용을 위하여 자신이 선정한 문자 및 숫자의 조합을
말합니다.
④ "비밀번호(패스워드)"라 함은 회원이 자신의 비밀보호를 위하여 선정한 문자 및 숫자의 조합을 말합니다.
제 3 조 (이용약관의 효력 및 변경)
① 이 약관은 당 사이트에 게시하거나 기타의 방법으로 회원에게 공지함으로써 효력이 발생합니다.
② 당 사이트는 이 약관을 개정할 경우에 적용일자 및 개정사유를 명시하여 현행 약관과 함께 당 사이트의
초기화면에 그 적용일자 7일 이전부터 적용일자 전일까지 공지합니다. 다만, 회원에게 불리하게 약관내용을
변경하는 경우에는 최소한 30일 이상의 사전 유예기간을 두고 공지합니다. 이 경우 당 사이트는 개정 전
내용과 개정 후 내용을 명확하게 비교하여 이용자가 알기 쉽도록 표시합니다.
제 4 조(약관 외 준칙)
① 이 약관은 당 사이트가 제공하는 서비스에 관한 이용안내와 함께 적용됩니다.
② 이 약관에 명시되지 아니한 사항은 관계법령의 규정이 적용됩니다.
제 2 장 이용계약의 체결
제 5 조 (이용계약의 성립 등)
① 이용계약은 이용고객이 당 사이트가 정한 약관에 「동의합니다」를 선택하고, 당 사이트가 정한
온라인신청양식을 작성하여 서비스 이용을 신청한 후, 당 사이트가 이를 승낙함으로써 성립합니다.
② 제1항의 승낙은 당 사이트가 제공하는 과학기술정보검색, 맞춤정보, 서지정보 등 다른 서비스의 이용승낙을
포함합니다.
제 6 조 (회원가입)
서비스를 이용하고자 하는 고객은 당 사이트에서 정한 회원가입양식에 개인정보를 기재하여 가입을 하여야 합니다.
제 7 조 (개인정보의 보호 및 사용)
당 사이트는 관계법령이 정하는 바에 따라 회원 등록정보를 포함한 회원의 개인정보를 보호하기 위해 노력합니다. 회원 개인정보의 보호 및 사용에 대해서는 관련법령 및 당 사이트의 개인정보 보호정책이 적용됩니다.
제 8 조 (이용 신청의 승낙과 제한)
① 당 사이트는 제6조의 규정에 의한 이용신청고객에 대하여 서비스 이용을 승낙합니다.
② 당 사이트는 아래사항에 해당하는 경우에 대해서 승낙하지 아니 합니다.
- 이용계약 신청서의 내용을 허위로 기재한 경우
- 기타 규정한 제반사항을 위반하며 신청하는 경우
제 9 조 (회원 ID 부여 및 변경 등)
① 당 사이트는 이용고객에 대하여 약관에 정하는 바에 따라 자신이 선정한 회원 ID를 부여합니다.
② 회원 ID는 원칙적으로 변경이 불가하며 부득이한 사유로 인하여 변경 하고자 하는 경우에는 해당 ID를
해지하고 재가입해야 합니다.
③ 기타 회원 개인정보 관리 및 변경 등에 관한 사항은 서비스별 안내에 정하는 바에 의합니다.
제 3 장 계약 당사자의 의무
제 10 조 (KISTI의 의무)
① 당 사이트는 이용고객이 희망한 서비스 제공 개시일에 특별한 사정이 없는 한 서비스를 이용할 수 있도록
하여야 합니다.
② 당 사이트는 개인정보 보호를 위해 보안시스템을 구축하며 개인정보 보호정책을 공시하고 준수합니다.
③ 당 사이트는 회원으로부터 제기되는 의견이나 불만이 정당하다고 객관적으로 인정될 경우에는 적절한 절차를
거쳐 즉시 처리하여야 합니다. 다만, 즉시 처리가 곤란한 경우는 회원에게 그 사유와 처리일정을 통보하여야
합니다.
제 11 조 (회원의 의무)
① 이용자는 회원가입 신청 또는 회원정보 변경 시 실명으로 모든 사항을 사실에 근거하여 작성하여야 하며,
허위 또는 타인의 정보를 등록할 경우 일체의 권리를 주장할 수 없습니다.
② 당 사이트가 관계법령 및 개인정보 보호정책에 의거하여 그 책임을 지는 경우를 제외하고 회원에게 부여된
ID의 비밀번호 관리소홀, 부정사용에 의하여 발생하는 모든 결과에 대한 책임은 회원에게 있습니다.
③ 회원은 당 사이트 및 제 3자의 지적 재산권을 침해해서는 안 됩니다.
제 4 장 서비스의 이용
제 12 조 (서비스 이용 시간)
① 서비스 이용은 당 사이트의 업무상 또는 기술상 특별한 지장이 없는 한 연중무휴, 1일 24시간 운영을
원칙으로 합니다. 단, 당 사이트는 시스템 정기점검, 증설 및 교체를 위해 당 사이트가 정한 날이나 시간에
서비스를 일시 중단할 수 있으며, 예정되어 있는 작업으로 인한 서비스 일시중단은 당 사이트 홈페이지를
통해 사전에 공지합니다.
② 당 사이트는 서비스를 특정범위로 분할하여 각 범위별로 이용가능시간을 별도로 지정할 수 있습니다. 다만
이 경우 그 내용을 공지합니다.
제 13 조 (홈페이지 저작권)
① NDSL에서 제공하는 모든 저작물의 저작권은 원저작자에게 있으며, KISTI는 복제/배포/전송권을 확보하고
있습니다.
② NDSL에서 제공하는 콘텐츠를 상업적 및 기타 영리목적으로 복제/배포/전송할 경우 사전에 KISTI의 허락을
받아야 합니다.
③ NDSL에서 제공하는 콘텐츠를 보도, 비평, 교육, 연구 등을 위하여 정당한 범위 안에서 공정한 관행에
합치되게 인용할 수 있습니다.
④ NDSL에서 제공하는 콘텐츠를 무단 복제, 전송, 배포 기타 저작권법에 위반되는 방법으로 이용할 경우
저작권법 제136조에 따라 5년 이하의 징역 또는 5천만 원 이하의 벌금에 처해질 수 있습니다.
제 14 조 (유료서비스)
① 당 사이트 및 협력기관이 정한 유료서비스(원문복사 등)는 별도로 정해진 바에 따르며, 변경사항은 시행 전에
당 사이트 홈페이지를 통하여 회원에게 공지합니다.
② 유료서비스를 이용하려는 회원은 정해진 요금체계에 따라 요금을 납부해야 합니다.
제 5 장 계약 해지 및 이용 제한
제 15 조 (계약 해지)
회원이 이용계약을 해지하고자 하는 때에는 [가입해지] 메뉴를 이용해 직접 해지해야 합니다.
제 16 조 (서비스 이용제한)
① 당 사이트는 회원이 서비스 이용내용에 있어서 본 약관 제 11조 내용을 위반하거나, 다음 각 호에 해당하는
경우 서비스 이용을 제한할 수 있습니다.
- 2년 이상 서비스를 이용한 적이 없는 경우
- 기타 정상적인 서비스 운영에 방해가 될 경우
② 상기 이용제한 규정에 따라 서비스를 이용하는 회원에게 서비스 이용에 대하여 별도 공지 없이 서비스 이용의
일시정지, 이용계약 해지 할 수 있습니다.
제 17 조 (전자우편주소 수집 금지)
회원은 전자우편주소 추출기 등을 이용하여 전자우편주소를 수집 또는 제3자에게 제공할 수 없습니다.
제 6 장 손해배상 및 기타사항
제 18 조 (손해배상)
당 사이트는 무료로 제공되는 서비스와 관련하여 회원에게 어떠한 손해가 발생하더라도 당 사이트가 고의 또는 과실로 인한 손해발생을 제외하고는 이에 대하여 책임을 부담하지 아니합니다.
제 19 조 (관할 법원)
서비스 이용으로 발생한 분쟁에 대해 소송이 제기되는 경우 민사 소송법상의 관할 법원에 제기합니다.
[부 칙]
1. (시행일) 이 약관은 2016년 9월 5일부터 적용되며, 종전 약관은 본 약관으로 대체되며, 개정된 약관의 적용일 이전 가입자도 개정된 약관의 적용을 받습니다.