• Journal of Chest Surgery
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• v.32 no.5
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• pp.480-483
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• 1999

The widely accepted method for coronary artery bypass grafting(CABG) is performing the distal coronary artery anastomoses on the flaccid and nonbeating heart with the aid of cardiopulmonary bypass(CPB) and cardioplegic arrest. However, current cardioplegic techniques are not consistent in avoiding myocardial ischemic damages especially in high risk patients undergoing CABG. In this regard, "Off-Pump" seems to be an ideal method for preventing myocardial ischemic damage and adverse effects during CPB. However, "Off-pump" CABG is not always technically feasible. We report 2 cases of "On-pump" CABG performed on the beating heart in high risk patients; The first patient had left ventricular dysfunction(Ejection Fraction=25%), and the second patient had cardiogenic shock after percutaneous transluminal coronary angioplasty.

• The Korean Journal of Nuclear Medicine
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• v.28 no.2
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• pp.172-176
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• 1994

As the Tc-99m-MIBI myocardial SPECT demonstrated wide application in the diagnosis of myocardial function, the quantitative and severity-dependent information is currently re quired. In this study, we proposed a computerized method for scoring the fixed defects in terms of extent-weighted severity and for identifying the reversibility in ischemic regions. At the first stage of this method, the transverse slices were reconstructed with 0.4 Nyquist freq. and order 5 Butterworth filter. From the oblique/sagittal slices, maximal count per pixel circumferential profiles were extracted for each sector, and then stress/redist. polar maps were normalized and plotted. For reversibility, the stress polar map was subtracted from the de-layed image and positive-valued pixels were categorized into three grades. The extent-weight-ed severity scores were calculated using the assigned grades and their number of pixels. This procedure was done automatically and the reversibility and severity scores were produced for each of the coronary territories (LAD, RCA, LCX) or any combination of these. Clinical ap-plication has shown that the changes In reversibility scores after PTCA were correlated linearly with the pre PTCA scores(r>0.8) in postinfarct cases as well as in angina, and severity scores of persistent defects in stress/rest SPECT study matched to the regional ejection fraction and visual analysis of regional wall motion of gated blood pool scan(r>0.6). We conclude that the computerized severity scoring method for the analysis of myocardial SPECT could be useful in the assessment of the myocardial ischemia and fixed defect.

• Journal of Chest Surgery
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• v.31 no.9
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• pp.837-844
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• 1998

Background: Adenosine is secreted by myocardial cells during myocardial ischemia or hypoxia. It has many beneficial effects on arrhythmias, myocardial ischemia, and reperfusion ischemia. Although many investigators have demonstrated that cardioplegia that includes adenosine shows protective effects in myocardial ischemia or reperfusion injury, reports of the optimal dose of adenosine in cardioplegic solutions vary. We reported the results of beneficial effects of single dosage(0.75 mg/Kg/min) adenosine by use of self-made Langendorff system. But it is uncertain that dosage was optimal. The objective of this study is to determine the optimal dose of adenosine in cardioplegic solutions. Material and Method: We used a self-made Langendorff system to evaluate the myocardial protective effect. Isolated rat hearts were subjected to 90 minutes of deep hypothermic arrest(15$^{\circ}C$) with modified St. Thomas' Hospital cardioplegia including adenosine. Myocardial adenosine levels were augmented during ischemia by providing exogenous adenosine in the cardioplegia. Three groups of hearts were studied: (1) group 1 (n=10) : adenosine - 0.5 mg/Kg/min, (2) group 2(n=10): adenosine -0.75 mg/Kg/min, (3) group 3 (n=10) : adenosine -1 mg/Kg/min. Result: Group 3 resulted in a significantly rapid arrest time of the heart beat(p<0.05) but significantly slow recovery time of the heart beat after reperfusion(p<0.05) compared to groups 1 and 2. Group 2 showed a better percentage of recovery(p<0.05) in systolic aortic pressure, aortic overflow volume, coronary flow volume, and cardiac output compared to groups 1 and 3. Group 1 showed a a better percentage of recovery(p<0.05) in the heart rate compared to the others. In biochemical study of drained reperfusates, CPK and lactic acid levels did not show significant differences in all of the groups. Conclusion: We concluded that group 2 [adenosine(0.75 mg/Kg/min) added to cardioplegia] has better recovery effects after reperfusion in myocardial ischemia and is the most appropriate dosage compared to group 1 and 3.

• Journal of Chest Surgery
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• v.37 no.9
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• pp.755-761
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• 2004

We evaluated the efficacy of Dor procedure in patients with ischemic left ventricular dysfunction. Material and Method: Between April 1998 and December 2002, 45 patients underwent the Dor procedure con-comitant with coronary artery bypass grafting (CABG). Left ventricular ejection fraction (LVEF) and left ventricular end-diastolic/end-systolic volumes (LVEDV/LVESV) were measured by echocardiography, myocardial SPECT, and cardiac catheterization and angiography performed at the sequence of preoperative, early postoperative, and one year postoperative stage. Result: Cardiopulmonary bypass and aortic clamp times were mean 141$\pm$64, 69$\pm$24 minutes, respectively. Intraaortic balloon pump (IABP) therapy was required in 19 patients (42%; 7 preoperatively, 9 intraoperatively, 3 postoperatively). Operative mortality rate was 2.2% (1/45). Postoperative morbidities were low cardiac output syndrome (12), atrial fibrillation (5), acute renal failure (4), and postoperative bleeding (4). Functional class (NYHA) was improved from classes 2.8 to 1.1 (p < 0,01). When we compared between the preoperative and early postoperative values, LVEF was improved from 32$\pm$9% to 52$\pm$11% (p<0.01). The asynergy portion decreased from 57$\pm$12% to 22$\pm$9%, and LVEDV/LVESV indexes improved from 125$\pm$39 mL/$m^2$, 85$\pm$30 mL/$m^2$ to 66$\pm$23 mL/$m^2$, 32$\pm$16 mL/$m^2$ (p<0.01). Although these changes in volumes were relatively preserved at postoperative one year, the left ventricular volumes showed a tendency to increase. Conclusion: After the Dor procedure for ischemic left ventricular dysfunction, LVEF improvement and left ventricular volume reduction were maintained till postoperative one year. The tendency for left ventricular volume to increase at postoperative one year suggested the requirement of strict medical management.

• Journal of Chest Surgery
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• v.31 no.3
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• pp.304-307
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• 1998

Aneurysm of the sinus of Valsalva on mostly congenital disease that develops more frequently in Orientals, is very low in incidence. In most cases, aneurysm of the sinus of Valsalva extends to intracardiac and results in ruptures into the right ventricle or atrium. The likelihood of extracardiac aneurysm of the sinus of Valsalva is very low. Cases of extracardiac aneurysm are usually accompanied by aortic regurgitation and can cause right ventricle outflow tract obstruction, myocardial ischemia, and myocardial infarction due to compression by aneurysm. Since the aneurysm can rupture in the intrapericardium and cause cardiogenic shock or sudden death, definite diagnosis and management are important. If confirmed, it is preferable operform a surgical correction. We report here, with a literature review, a case where myocardial ischemia and aortic egurgitation caused by aneurysm developed in the left coronary and noncoronary sinus, and were surgically corrected with satisfactory esults.

• Journal of Chest Surgery
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• v.41 no.5
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• pp.636-639
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• 2008

An abnormal origin of the right coronary artery can be responsible for sudden death, myocardial ischemia, arrhythmia and syncope, and it may be associated with the accelerated development of atherosclerotic disease. The mechanisms of ischemia in the case of an abnormal origin of the right coronary artery are currently unclear and several surgical methods have been proposed to treat this malady. Multidetector Computed Tomography shows the course of the abnormal coronary artery, it helps to clarify the mechanism of the ischemia and it aids in choosing the best surgical approach. We report here on a case of acute myocardial infarction with an abnormal origin of the right coronary artery. Coronary artery bypass grafting was subsequently carried out to treat this patient.

• Journal of Chest Surgery
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• v.33 no.7
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• pp.576-580
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• 2000

Transmycardial laser revascularization has made its position as a sole therapy for patients with chronic angina nonamenable to maximal medical therapy, percutaneous transluminal coronary angioplasty, and coronary artery bypass grafting. We report three cases of transmyocardial laser revascularization as a sole therapy for patients with recurrent angina after CABG.

• Journal of Chest Surgery
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• v.29 no.10
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• pp.1055-1065
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• 1996

This experiment was undertaken to assess the effect of nitric oxide, isosorbide dinitrate, and sodium nitroprusside, which are known to increase coronary flow by vasodilation and to improve the cardiac function of an ischemic heart The experiment was carried out to investigate the effect of nitric oxide on the coronary artery of an ischemic rat myocardium using isolated constant pressure Langendorfr system. The experimental parameters were lactate and CK-MB for the frozen myocardium and coronary flow. the quantity of coyonary flow, left ventricular developed pressure (LVDP), and dp/dt. The experimental groups were decided as control group (Group I), nitric oxide group (Group II), Iso orbide dinitrate group (Group III) and sodium nitroprusside group (Group IV). Statistical analysis was performed using repeated measured analysis of variance and 2tudent t-test The results were as follows: 1 . The lactic acid contents of group II and IV were less than other groups for the frozen myocardium at preischemic state (p< 0.0025), whereas the determined coronary flows were higher. 2. In the ratio of produced lactic acid between the preischemia and reperfusion for the coronary flow, group II and IV exhibitrod less value than others (p< 0.005). 3. Group II and III were less than others in the coronary flow for the quantity of CK-MB, but or the frozen myocardium, group II and IV were less. 4. Group II and IV showed higher coronary flow compared to others throughout entire experimental period (p< 0.005). 5. Group II was highest at the preischemic state for the left ventricular developed pressure. 6. The +maximal dp/dt of group II was highest compared to others. 7. Group I exhibi ed the highest recovery rate of coronary flow between prelschemla and reperfusion. 8. The(-dp/dt)1(+dp/dt) ratio was 116%, 100%, 100%, and 55% for the 4 groups, respectively And the recovery rate of total dp/dt was 34%, 67%, 51%, and 76% for the four groups, respectively.

• Journal of Biomedical Engineering Research
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• v.16 no.2
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• pp.223-230
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• 1995

This study investigates a combined mathematical model for the quantitative estimation of regional myocardial blood flow in experimental canine coronary artery occlusion and in patients with ischemic myocardial diseases using Rb-82 dynamic myocardial positron emission tomography. The coronary thrombosis was induced using the new catheter technique by narrowing the lumen of coronary vessel gradually, which finally led to partial obstruction of coronary artery. Thirty four Rb-82 dynamic myocardial PET scans were performed sequentially for each experiment using our 5, 10 and 20 second acquisition protocol, respectively, and six to seven regions of interest were drawn on each transaxial slices, one on left ventricular chamber for input function and the others on normal and decreased perfusion myocardial segments for the flow estimation in those regions. Two compartment model and graphical analysis method have been applied to the measured sets of regional PET data, and the rate constants of influx to myocardial tissue were calculated for regional myocardial flow estimates with the two parameter fits of raw data by the Levenberg-Marquardt method. The results showed that, (I) two compartment model suggested by Kety-Schmidt, with proper modification of the measured data and volume of distribution, could be used for the simple estimation of regional myocardial blood flow, (2) the calculated regional myocardial blood flow estimates were dependent on the selection of input function, which reflected partial volume effect and left ventricular wall motion in previously used graphical analysis, and (3) mathematically fitted input and tissue time activity curves were more suitable than the direct application of the measured data in terms of convergence.

• The Korean Journal of Pharmacology
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• v.27 no.2
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• pp.109-118
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• 1991

The present study was conducted to assess the possible contribution of arachidonic acid to generation of reactive oxygen metabolites and myocardial damage in ischemic-reperfused heart. Langendorff preparations of isolated rat heart were made ischemic by hypoperfusion (0.5 ml/min) for 45 min, and then followed by normal oxygenated reperfusion (7 ml/min). The generation of superoxide anion was estimated by measuring the SOD-inhibitable ferricytochrome C reduction. The myocardial cellular damage was observed by measuring LDH released into the coronary effluent. Oxygenated reperfusion following a period of ischemia produced superoxide anion, which was inhibited by both indomethacin (60 nmole/ml) and ibuprofen $(30\;{\mu}g/ml)$. Sodium arachidonate $(10^{-7}-10^{-2}{\mu}g/ml)$ administered during the period of oxygenated reperfusion stimulated superoxide anion production dose-dependently. The rate of arachidonate-induced superoxide generation was markedly inhibited by indomethacin, a cyclooxygenase inhibitor; nordihydroguaiaretic acid (NDGA), a lipoxygenase inhibitor, and by eicosatetraynoic acid (ETYA), a substrate inhibitor of arachidonic acid metabolism. The release of LDH was increased by Na arachidonate and was inhibited by superoxide dismutase. The release of LDH induced by arachidonic acid was also inhibited by indomethacin, NDGA and ETYA. In conclusion, the present result suggests that arachidonic acid metabolism is involved in the production of reactive oxygen metabolite and plays a contributory role in the genesis of reperfusion injuy of myocardium.