• Journal of Chest Surgery
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• v.20 no.3
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• pp.536-543
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• 1987

The Fontan procedure was physiological correction which was initially applied to tricuspid atresia. We had used the modified Fontan operation in 8 cases at National Medical Center, Seoul, from Aug. 1984 to Oct. 1986. Age range was 20 months to 15 years [mean: 9 years] and male: female ratio was 5:3. 5 patients had tricuspid atresia [lb: 2 cases, Ic: 1 case, lib: 1 case, & llc: 1 case], 2 Patients had univentricular heart of left ventricular type, and one patient had transposition of great arteries with complete endocardial cushion defect. The operative principle was direct anastomosis between right atrium and pulmonary artery, whether main pulmonary artery or right pulmonary artery without any conduits. Postoperatively all patients needed high central venous pressure for adequate hemodynamic status in both survival [20-24 CmH2O] and mortality groups [20-24 CmH2O]. The fatal complications were as follows: empyema with bronchopleural fistula [1 case], bleeding tendency & brain damage [1 case], low cardiac output syndrome & acute renal failure [2 cases], and right to left shunt of unknown origin [1 case]. There were 5 hospital deaths; 3 of 5 tricuspid atresia patients, 1 of 2 univentricular heart patients, and 1 of 1 transposition of great arteries with complete endocar4ial cushion defect patient. The overall mortality was 62.5%. 3 survivors were nearly compatible with Choussat & Fontan criteria. Thus appropriate patient selection and experienced surgical technique were required for good results.

• Journal of Chest Surgery
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• v.16 no.1
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• pp.91-96
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• 1983

A study was carried out to observe the clinical progress and results after modified Blalock-Taussing shunts on II patients with cyanotic complex heart diseases unsuitable for corrective surgery. The operation was performed by interposing a vascular prosthesis [PTEE] between the left subclavian artery and the left pulmonary artery. Vascular prostheses larger than the diameter of left subclavian artery were selected. The results were as follows: 1. The postoperative courses in 10 patients were uneventful without any complications. One patient died of low cardiac output syndrome immediate postoperatively. 2. The average value of RBC count before operations was 751.2291.68 [xl00]/cubic mm. It was decreased to 588.11 90.45 [xl 0,000]/cubic mm. After the operation. 3. The average value of Hemoglobin before operations was 20.07 3.01 mg/dl. The value was decreased to 15.361.68mg/dl after the operation. 4. The value of Hematocrit before operations was 62.878.89%. The value was decreased to 49.6 5.84% 5. Patency after the shunt operations using PTFE was good for maximal 16 months follow-up period. 6. The physiological impairment like anoxic spells, degree of cyanosis and other clinical symptoms were markedly improved after the shunt operations. Although a longer follow-up seems to be necessary to assess the validity of these shunts, the early results were encouraging.

• Journal of Chest Surgery
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• v.17 no.4
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• pp.657-665
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• 1984

Thirty-seven patients had undergone repair of a endocardial cushion defect between 1977 and Aug. 1983 in Seoul National University Hospital. Twenty eight had a partial defect, one intermediate defect and eight complete endocardial cushion defect. Tricuspid cleft was found in 4 cases and mitral cleft was in all p-ECD. Seven patients were of type C anatomy in c-ECD. Four patients had associated major anomalies, including three TOF in c-ECD, one coarctation in p- ECD. In p-ECD patients, the septal defect was closed with patch in all cases and the atrioventricular valvular insufficiency was corrected with MVR in 4 cases, TVR in 1 case and simple interrupted sutures in remainders. In c-ECD patients the septal defect was closed with single patch except one case. The atrioventricular valve was repaired with simple interrupted sutures except one MVR and TVR case. The operative mortality was 14.2% in p-ECD, 44.4% in c-ECD, but recent 3 years [1980-1983] mortality was 8.7% in p-ECD, 20% in c-ECD. More than grade III systolic regurgitant murmur was oted postoperatively in 4 cases of c-ECD and 3 cases of p-ECD. The operative risk factors were preoperative NYHA classification, cyanosis, Rp/Rs, systolic pressure of main pulmonary artery and the degree of regurgitation of atrioventricular valves. The causes of death were low cardiac output syndromes, pulmonary complications and arrhythmias.

• Journal of Chest Surgery
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• v.17 no.3
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• pp.418-423
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• 1984

Appreciation of the large volume deficits which may occur in surgical or trauma patients due to blood loss has led to vigorous transfusion techniques designed to overt hypovolemic shock and ischemic damage to vital organs which may develop in minutes during the hypovolemic state. In a significant proportion of patients treated with massive rapid blood or fluid transfusion, hypervolemia occurs and life threatening pulmonary edema may develop. Especially, hypervolemia may occur during transfusion for preventing development of the so-called low output syndrome following cardiac surgery. However, the most effective indicator which reveals the adequate level of transfusion is not settled yet. The present study was aimed to compare the effectiveness of the indicators suggested thus far and to determine the most sensitive one. Eight dogs were experimentally studied in terms of left atrial pressure, pulmonary arterial systolic pressure, central venous pressure, mean systemic arterial pressure and heart rate before and after induced hypervolemia with infusion of 600ml heparinized homologous blood. Immediately after induced overtransfusion of the blood, pulmonary arterial systolic pressure increased 75.0%, in omparison with the control before transfusion, left atrial pressure 58.8%, central venous pressure 44.6%, and mean systemic arterial pressure 10.1%, one hour after transfusion, pulmonary arterial systolic pressure 40.0%, left atrial pressure 21.2%, central venous pressure 14.5%, and mean systemic arterial pressure 3.2%, central venous pressure 14.5%, and mean systemic arterial pressure 3.2%, respectively. Heart rate showed no significant change throughout the experiment. These result suggested that the changes of the pulmonary arterial systolic pressure is the most sensitive indicator for detection of hypervolemia during blood transfusion.

• Journal of Chest Surgery
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• v.17 no.4
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• pp.557-564
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• 1984

Of the valve replacement patients operated between 1983 and June, 1984, 75 patients need more than 60 minutes of aortic cross-clamping time. 42 patients performed single valve replacement [35 MVR, 7 AVR with or without TAP] and remainder needs double valve replacement with or without TAP. The average aortic clamping time was 95.1 minutes. They need 30 minutes more extra-corporeal circulation time than aortic clamping time. The patients were divided into two groups by usage of cardioplegic solution. Group I [n=31] with Bretschneider solution and group II with potassium cardioplegic solution [M.G.H. modification] were analyzed by extra-corporeal circulation data,/CG and Echocardiography findings, and clinical data. There was no difference between two groups in Bivon addition amounts [cc/kg] and E.F. and S.F. by echocardiography, group I need 1 more electrocardioversion to convert sinus rhythm postoperatively. Also no difference could be found in patients whose preoperative C.I. was above 2.0 between two group. But significant postoperative decrease in E.F. was found in group I whose preoperative C.I. was below 2.0. Relatively longer ECC time was also needed in same group. Ischemic changes in ECG and low cardiac output syndrome was, however more prevalent in groupII. As a whole, the clinical data was satisfactory with both cardioplegic solution in clinical practice.

• Journal of Chest Surgery
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• v.28 no.5
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• pp.437-442
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• 1995

We developed an experimental model of brain death using dogs. Brain death was caused by increasing the intracranial pressure[ICP suddenly by injecting saline to an epidural Foley catheter in five female mongrel dogs[weight, 20-25Kg .Hemodynamic and electrocardiographic changes were evaluated continuously during the process of brain death. 1. Abrupt rise of ICP after each injection of saline followed by a rapid decline to a new steady-state level within 15 minutes and the average volume required to induce brain death was 7.6$\pm$0.8ml.2. Body temperature, heart rate, mean pulmonary arterial pressure, left ventricular[LV enddiastolic pressure and cardiac output was not changed significantly during the process of brain death, but there was an increasing tendency.3. Mean arterial pressure and LV maximum +dP/dt increased significantly at the time of brain death.4. Hemodynamic collapse was developed within 140 minutes after brain death.5. Marked sinus bradycardia followed by junctional rhythm was seen in two dogs and frequent VPB`s with ventricular tachycardia was observed in one dog at the time of brain death. Hyperdynamic state develops and arrhythmia appears frequently at the time of brain death. Studies on the effects of brain death on myocardium and its pathophysiologic mechanism should be followed in the near future.

• International Journal of Vascular Biomedical Engineering
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• v.4 no.1
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• pp.9-16
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• 2006

In this article we introduce computer models that have been developed in the past to determine the concentration of metabolic gases, the oxygen and carbon dioxide, along the pulmonary circulation. The terminal concentration of these gases in the arterial blood is related with the total change of the partial pressure of the same gases in the alveoli for the time beginning with inspiration and ending with expiration. It is affected not only by the ventilation-perfusion ratio and the gas diffusion capacity of the lung membrane but also by the pulmonary defect such as shunt, dead space, diffusion impairment and ventilation-perfusion mismatch. Some pathological pulmonary symptoms such as ARDS and CDPD can be understood through the mathematical models of these pulmonary dysfunctions. Quantitative study on the blood oxygenation process using various computer models is therefore of foremost importance in order to monitor not only the pulmonary health but also the cardiac output and cell metabolism. Reviewed in this paper include the basic and advanced methods that enable numerical study on the gas exchange and on the arterial oxygenation process, which might depend on the various heart and lung physiological conditions listed above.

• YAKHAK HOEJI
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• v.38 no.2
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• pp.191-196
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• 1994

Higenamine is a tetrahydroisoquinoline alkaloid which was isolated as a cardiotonic principle from Aconiti tuber. 1.v. injection of higenamine was reported to increase the cardiac output and heart rate and to decrease the blood pressure and the systemic vascular resistance presumably by stimulating the adrenergic ${\beta}-receptors$. The anti-platelet and anti-thrombotic effects of higenamine were investigated in this paper. Higenamine(0.5 mg/ml) showed mild inhibitory effect against collagen induced platelet aggregation in vitro and the inhibito교 effect was increased with the pre-incubation$(5{\sim}30\;min)$ of platelet rich plasma(PRP) with higenamine. With the 30 min incubation, the platelet aggregation was almost completely inhibited. And the oral administration of higenamine$(50{\sim}200\;mg/kg)$ enhanced the survival in the mouse model of thrombosis and that of endotoxic shock. The anti-thrombotic and anti-septic effects of higenamine thus appear to be due to the ${\beta}-agonistic$ and the anti-platelet effects of this compound.

• Journal of Chest Surgery
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• v.33 no.1
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• pp.45-50
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• 2000

Background: The CarboMedics prosthetic heart valve was produced in an attempt to improve the existing valve designs and was especially concerned with easily the implantation and further reduction of turbulence. Precise positioning of the valve in situ was achieved by the abilityof the valve to rotate relative to the sewing ring. Improved monitoring is possible due to increased radiopacity and the dacron sewing ring is coated with carbon to reduce pannus overgrowth. The leaflets have an opening angle of 78 degrees that apparently allows a rapid synchronous closure The aim of this study was to analyze the clinical performance of the CarboMedics valve prostheses(45 mitral 13 aortic and 7 double aortic-mitral valve replacement) were implanted in 65 patients(mean age 48.75$\pm$9.74 years) Result: The operative mortality was 3.1%(2/65) causes of death were low cardiac output syndrome. Total follow up was 1831 patient-months and mean follow up was 29.06$\pm$10.97 months/patient. No structural failure hemorrhage valve thrombosis and late death have been observed. Embolism occurred at a rate of 0.65%/Patient-year. Actuarial survival and thrombo-mbolism free rate at 36 months were 96.9% and 98.4% respectively. Consclusions: The CarboMedics valve stands for low valve related complicatons.

• Journal of Institute of Control, Robotics and Systems
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• v.1 no.2
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• pp.127-134
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• 1995

For use in patients with severe forms of heart disease for which no surgical repair is possible, development of artificial hearts has many importance in point of economics, medical and industrial applications. To provide a sufficient cardiac output to the physiological demands of circulatory systems is the objective of control systems for an electromechanical artificial heart, which is based on the stable controller design for the motor in the artificial heart. In this paper, an implantable microcontroller-based brushless DC motor control system with the implantability, reliability, and stability is introduced. The developed control system for the artificial heart has the following advantages: (1) It is possible to be implanted in a body by realizing the fundamental functions such as a motor speed detection, proportional-intergral control, timer, and PWM generation through a software programming. (2) Thus, the power consumed in the controller is reduced. (3) The reliability and stability are improved through the reduction of electronic parts and line connetions at the controller. The performance of the artificial hearts and control system developed was evaluated through a series of mock circulatory experiments and a reliability test for one and half years. A sheep with the artificial heart and control system was survived for three days.