• 대한의용생체공학회:의공학회지
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• 제13권4호
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• pp.285-298
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• 1992

An analysis of the dynamics in the closing phase of the occluder of a mechanical monoleaflet heart valve prosthesis is presented. The dynamic analysis of the fluid in the vicinity of the occluder was based on the control vo]use approach. The backflow velocity of the fluid was computed by applying the continuity, Bernoulli's and momentum equations in the unsteady state. By considering the fluid pressure and gravity as external forces acting on the occluder, the moment equilibrium on fine occluder was employed to analyze the motion of the occluder during closing and the force of impact between the occluder and the guiding struts. Occluder comes to rest after several oscillations in about 10-18 msec after the Inltiaton of closing. As the aortic pressure increases, the occludes closes faster and comes to the final resting position earlier and the impact force increases also. But backflow is not af footed by the variation of the aortic pressure. With decreasing time delay of the ventricle pressure, the occluder closes faster and impact force Increases. The computed magnitudes of the occluder tiP velocities as well as the backflow of the fluid during the closing phase using this model were in agreement with previously reported experimental measurements.

• 대한기계학회논문집
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• 제19권2호
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• pp.443-450
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• 1995

An analysis of the dynamics of a mechanical monoleaflet heart valve prosthesis in the closing phase is presented. Employing the moment equilibrium principles on the occluder motion and the squeeze film dynamics of the fluid between the occluder and the guiding strut at the instant of impact, the velocity of the occluder tip and the impact force were computed. The dynamics of fluid being squeezed between the occluder and the guiding struts is accounted for by Reynold's equation. The effect of the fluid being squeezed between the occluder and the guiding strut was to reduce the velocity of the occluder tip at the instant of valve closure as well as dampen the fluttering of the occluder before coming to rest in the fully closed position. The squeeze film fluid pressure changed rapidly from a high positive value to a relatively large negative value in less than 1 msec. The results of this study may be extended for the analysis of cavitation inception, mechanical stresses on the formed elements and valve components as well as to estimate the endurance limits of the prosthetic valves.

• 한국임상수의학회지
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• 제33권4호
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• pp.221-224
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• 2016

An 8 month-old male Maltese (weighing 2.0 kg) was referred with loud heart murmur at routine physical exam in local animal clinic. Electrocardiogram found left ventricular hypertrophy pattern (4.5 mV R-wave). Diagnostic imaging studies revealed the elongation of left ventricle (LV) with classic triple bumps on the main pulmonary artery, aorta and left atrium on the ventrodorsal view of radiograph. Echocardiography revealed patent ductus arteriosus (PDA) duct and continuous turbulent shunt flow (maximal velocity 4.83 m/s) between the aorta and pulmonary artery with left to right direction. The PDA in this dog was successfully closed through femoral vein (transvenous approach) using a 5 mm Amplatz$^{(R)}$ Canine Duct Occluder. To the best of author's knowledge, this is the first case of PDA occlusion treated with Amplatz Canine Duct Occluder through femoral vein.

• 대한기계학회논문집
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• 제16권11호
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• pp.2090-2097
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• 1992

본 연구에서는 밸브판의 거동을 2차의 회전계로 간주하고, 양력 및 항력(drag force)을 구하는데 있어 Reif등이 구한것과 동일한 방법을 이용하되 정지핀에 의해 그 최대 열림각이 제한을 받는 물리적 사실을 고려하고, 밸브를 통과하는 유량도 단위 입 력이 아닌 정현파(sine wave)로 간주하여 밸브판의 동적거동을 해석하였다. 해석대 상의 밸브 모델로는 Bjork-Shiley 27mm 1엽 밸브를 선정하였다.

• 대한수의학회지
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• 제50권1호
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• pp.49-53
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• 2010

A 5-year-old female Cocker spaniel dog (body weight 7.0 kg) was presented with primary complaints of exercise intolerance and loud precordial thrill which was noticed since she was a puppy. Physical examination revealed a grade V/VI continuous murmur over the maximal point of the left basal area, bounding femoral pulse, but no differential cyanosis. Tall R waves were detected in electrocardiogram, suggesting left ventricular enlargement. Diagnostic imaging studies showed enlarged left ventricle, bulged descending aorta (dAo), markedly dilated right pulmonary artery, and continuous shunt flow between the dAo and main pulmonary artery. Based on these findings, the dog was diagnosed as left to right shunted patent ductus arteriosus (PDA). The patent ductus arteriosus was treated by lodging a PDA duct occluder via the transvenous approach. Clinical signs were markedly improved after the ductal occlusion, the shunt flow was mildly persistent. The case presented is the first case of PDA occluded by the PDA duct occluder via the transvenous approach in a small breed of dog. Although the residual shunt flow was mildly persisted, the dog was clinically normal without detectable murmurs.

• Journal of Chest Surgery
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• 제50권1호
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• pp.47-49
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• 2017

Percutaneous closure of atrial septal defect (ASD) has become an increasingly common procedure. Serious complications of the procedure, such as cardiac migration, are rare, and usually occur <72 hours after device placement. In this report, we present the case of a patient who underwent successful surgical treatment for the migration of an ASD occluder device to the thoracic aorta 12 months after ASD closure.

• 대한수의학회지
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• 제57권1호
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• pp.51-54
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• 2017

A 9-month-old intact male Maltese dog (1.52 kg) was diagnosed with a patent ductus arteriosus (PDA). Transcatheter occlusion of the PDA was performed by using the Amplatz canine duct occluder (ACDO). After occlusion, reflex bradycardia occurred and lasted for at least 15 h with normal systolic arterial pressure and slightly increased diastolic arterial pressure. The bradycardia slowly resolved, and the heart rate was normal in re-examinations after 7 and 30 days. This is the first case of reflex bradycardia after ACDO implantation, in which the bradycardia continued for a long time, even after recovery from anesthesia.

• 대한의용생체공학회:의공학회지
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• 제13권3호
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• pp.235-244
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• 1992

In this paper, fluttering behavior of mechanical monoleaflet tilting disc heart valve prostheses during the opening phase was analyzed taking into consideration the impact between the occluder and the guiding strut at the fully open position. The motion of the valve occluder was modeled as a rotating system, and equations were derived by employing the moment equilibrium principle. Forces due to lift, drag, gravity and buoyancy were considered as external forces acting on the occluder. The 4th order Runge-Kutta method was used to solve the governing equations. The results iimonstrated that the occludes reaches steady equilibrium position only after damped vibration. Fluttering frequency varies as a function of time after opening and is in the range of 8-84 Hz. Valve opening appears to be affected by the orientation of the valve relative to gravitational force. The opening velocities are in the range of 0.65-1.42m/sec and the dynamic loads by impact of the occludes and the strut are in the range of 90-190 N.

• Journal of Chest Surgery
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• 제54권3호
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• pp.214-217
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• 2021

In rare cases, levoatrial cardinal vein may occur as an isolated condition without additional congenital anomalies. Depending on the direction and flow of the shunt, this pathology may produce symptoms; alternatively, it may be asymptomatic, as in the case presented in this study. In asymptomatic cases, complications, such as paradoxical embolism and brain abscess, can arise later. In the 11-year-old patient whose case is presented here, the levoatrial cardinal vein was asymptomatic and incidentally detected. The percutaneous closure method was applied first. However, by 16 hours after the procedure, the occluder device had embolized to the iliac artery. Emergency surgery was performed; first, the occluder device was removed, and levoatrial cardinal vein ligation was then performed via a mini-thoracotomy. The symptoms, diagnosis, and treatment modalities of isolated levoatrial cardinal vein are discussed in the context of this case described herein.

• 한국임상수의학회지
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• 제29권6호
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• pp.498-501
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• 2012

10개월의 수컷 말티즈견 (1.6 kg)이 간헐적인 기침과 지속성 심잡음을 주증으로 내원 하였다. 환축은 경흉부심초음파 검사와 혈관 조영검사를 통하여 좌우단락의 동맥관개존증 (PDA)으로 진단되었다. 혈관조영 검사를 통하여 동맥관의 형태 및 크기에 대해 평가한 뒤, 대퇴동맥으로 $Amplatz^{(R)}$ Canine Duct Occluder (ACDO) 장치를 삽입하는 투시 유도하 동맥관 폐쇄술이 시도되었다. 동맥관의 폐쇄직후 지속성 심잡음이 사라졌으며, 시술 후 실시된 혈관조영검사를 통하여 잔류혈류가 관찰되지 않았다. 투시 유도하에서 ACDO 장착 및 성공적인 동맥관의 완전폐쇄가 확인되었다. 환자는 시술 1일 뒤 퇴원하였으며, 임상증상 관찰 및 심장검사가 정기적으로 이루어 졌다. 시술 후 합병증은 발생하지 않았다. 결론적으로 본 증례의 경우 대퇴동맥내로 ACDO를 적용한 성공적인 동맥관개존증 폐쇄술에 대한 국내 첫 증례보고이다.