• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.8
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• pp.715-720
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• 2014

In order to maximize the effect of left ventricular assist device (LVAD) on ventricular unloading, the therapy should be begun at appropriate level of heart failure severity. We predicted pumping efficacy of LVAD according to the severity of heart failure theoretically. We used 3 dimensional finite element model of ventricle coupled with 6 Wind-kessel compartmental model of vascular system. Using the computational model, we predicted cardiac responses such as contractile ATP consumption of ventricle, left ventricular pressure, cardiac output, ejection fraction, and stroke work according to the severity of ventricular systolic dysfunction under the treatments of continuous LVAD. Contractile ATP consumption, which indicates the ventricular energetic loading condition decreased maximally at the $5^{th}$ level heart-failure under LVAD therapy. We conclude that optimal timing for LVAD treatment is $5^{th}$ level heart-failure when considering LVAD treatment as "bridge to recovery".

• Journal of Chest Surgery
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• v.32 no.11
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• pp.1017-1022
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• 1999

Background: An increasing number of elderly are referred for open heart surgeries(OHS). These patients are assumed to have significantly increased morbidity and mortality because of compromised functional reserves in their vital organs. We reviewed the results of OHS patients who were 70 years old or older. Material and Method: Thirty six consecutive septuagenarians underwent OHS from 1995 to 1997. Operations were coronary artery bypass grafting(CABG) in 26 including 3 left main surgical angioplasty, valve replacement in 7, MVR+CABG in 2, and ASD closure+TAP in 1. Statistical tests were carried out to compare survivor group with nonsurvivor group in respect to risk factors including NYHA functional class, LVEF, emergent operation, IABP support, CPB/ACC time, ventilator time cardiac index, ICU stay and hospital stay for operative mortality. Result: Operative mortality rate and postoperative complication were 16%(6/36) and 50%(18/36). One-year and 3-year actuarial survival rates were 76%. Nine patients(25%) had major complications including third-degree A-V block(2), respiratory failure(1), stroke(3), renal failure requiring dialysis(3) and postoperative hemorrhage(2). The causes of death were pneumonia(1), bleeding(1), acute renal failure(1), low cardiac output(1), third-degree A-V block(1), and ventricular tachycardia(1). The univariate analysis of mortality shows that NYHA class IV, LVEF<40%, lesser values for C.I, and longer time for ventilatory support were associated with the risk factors(p value=0.03, 0.001, 0.007, and 0.014). The emergent operation, CPB/ACC time, IABP support, ICU stay and hospital stay were not significant. Conclusion: We conclude that cardiac operation can be performed in septuagenarians with acceptable outcomes when done in patients with normal to moderately depressed left ventricular function and adequate functional reserves in their vital organs.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.4
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• pp.283-289
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• 2013

This study was designed to evaluate the protective effect of Korean red ginseng (KRG) against ischemia/reperfusion (I/R) injury in isolated guinea pig heart. KRG has been shown to possess various ginsenosides, which are the major components of Panax ginseng. These components are known naturally occurring compounds with beneficial effects and free radical scavenging activity. The heart was induced to ischemia for 60 min, followed by 120 min reperfusion. The hearts were randomly allocated into five groups (n=8 for each group): normal control (N/C), KRG control, I/R control, 250 mg/kg KRG group and 500 mg/kg KRG group. KRG significantly increased hemodynamics parameters such as aortic flow, coronary flow and cardiac output. Moreover, KRG significantly increased left ventricular systolic pressure (LVSP), the maximal rate of contraction (+dP/$dt_{max}$) and maximal rate of relaxation (-dP/$dt_{max}$). Also, treatment of KRG ameliorated electrocardiographic index such as the QRS, QT and RR intervals. Moreover, KRG significantly suppressed the lactate dehydrogenase, creatine kinase-MB fraction and cardiac troponin I and ameliorated the oxidative stress markers such as malondialdehyde and glutathione. KRG was standardized through ultra performance liquid chromatograph analysis for its major ginsenosides. Taken together, KRG has been shown to prevent cardiac injury by normalizing the biochemical and oxidative stress.

• Journal of Chest Surgery
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• v.23 no.5
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• pp.844-853
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• 1990

We have performed 27 cases of orthotopic homologous cardiac transplantation using Korean mongrel dogs and one case of sham operation for the evaluation of harmful effect of cardiopulmonary bypass itself on the dog from April, 1989 to June, 1990. Our previous reports have already demonstrated basal hemodynamic and hematologic data on the canine homologous heart transplantation and the fundamental principles of transplantation of the heart. The mean body weight of recipients was 13.2$\pm$1.2kg with a rage of 11 ~ 15kg, and the hemodynamic and hematologic pictures were almost same as the result of previous reports from our hospital, except marked decrease in postoperative platelet count[from 3.18 $\pm$0.80x106/mm3 to 1.41$\pm$0 37x 106/mm3]. Mean survival time was 24.82$\pm$49.40 hours with the longest survival of 264 hours. Donor cardiectomy included coronary vasodilatation with diltiazem, potassium arrest, and the rapid cooling of the heart suspending in the specially designed ice-bath. Median sternotomy provided excellent exposure of the surgical field. 6 \ulcorner0 prolene suture was used for the anastomosis of both atrial cuffs and the great arteries, and we found the fact that stenosis, bleeding, thrombus formation around the anastomotic site could be decreased with the use of everted horizontal mattress suture techniques. Immunosuppression was done with a combination of lower dose Cyclosporin-A, Azathioprine, methyl-prednisolone, but our cases still showed too short survival to worry about graft rejection. Still poor was our quality control of experimental animal, we had much difficulties in postmortem evaluation of the dogs. Low cardiac output due to biventricular failure, intractable supraventricular or ventricular tachyarrhythmia, postoperative massive bleeding, sepsis were most frequent findings that could be thought as a cause of death. A few cases showed subendocardial patch hemorrhage in both ventricular cavity or atrial septum at autopsy, suggesting acute subendocardial infarction. Although our team overcome most of the technical problems of orthotopic heart transplantation, we should pile up further knowledges about donor heart preservation, quality control of animal, infection, rejection, the effect of the cardiopulmonary bypass to improve the results.

• Journal of Chest Surgery
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• v.12 no.3
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• pp.207-214
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• 1979

This 3-year-old girl was observed frequent exertional dyspnea and cyanosis at crying since birth. She was not premature baby and delivered at full term normally. On physical examination, she was underdeveloped-body weight 13.5 kg, height 99 cm.- and cyanotic. There was severe clubbing on fingers. There was grade II/VI ejection systolic murmur on left lateral border of the sternum. The preoperative examinations [EKG, echocardiogram, cardiac catheterization and biventriculogram] showed that complicated T.G.A. combined vena cava[S.D.D.]. Preoperatively, we decided the corrective surgery of Rastelli operation using a. pulmonary valved conduit. The operation was performed under total circulatory arrest using deep profound hypothermia combining with extracorporeal circulation. On operation, the anatomy of the heart showed that, 1. The subaortic conus was seen and subaortic muscles were hypertrophied. 2. The VSD[type II], behind the subaortic conus-about 1 cm. in diameter, was visible only through LV cavity and, 3. The pulmonary valve ring was hypoplastic and pulmonary valvular stenosis was seen also. The subpulmonic area [LV outflow tract] was obstructed with hypertrophied muscle and mitral valve. 4. Left superior vena cava was drained to RA via coronary sinus. 5. LAD coronary artery was originated from right coronary artery and ran anterior to the pulmonary artery. According to above anatomy, we performed the VSD closure with Teflon patch, and Mustard operation combined with LV-to-pulmonary artery bypass graft using the valve contained [Hancock 16 mm] conduit. Postoperatively, adequate blood pressure could be maintained under the state of using inotropic agent [epinephrine]. On the second postoperative day, the patient died of cardiac arrest due to low cardiac output syndrome, acute renal failure and pulmonary edema.

• The Korean Journal of Nuclear Medicine
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• v.17 no.1
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• pp.11-15
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• 1983

Left ventricular volume would be useful in the diagnosis and treatment of patients with various heart diseases. So we measured left ventricular volume index using gated blood pool nuclear cardiac angiography which was easy to perform, non-invasive, and capable of repetitive studies. These left ventricular volume indices were compared with left ventricular volumes by quantitative cardiac cine-angiography and the results were as follows, 1. The correlation coefficient between left ventricular volume indices and left ventricular volumes was 0.829 (p<0.001). 2. The correlation coefficient between left ventricular volume indices and absolute left ventricular volumes which were obtained by measurement of cardiac output of patients. 3. There were good correlation in intraobserver and interobserver analysis.

• Journal of Chest Surgery
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• v.25 no.2
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• pp.125-130
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• 1992

To evaluate the effect of oxygenation[95% O2+5% CO2] of St. Thomas Hospital No.2 cardioplegic solution[Plegisol], 20 isolated perfused rat hearts were studied under hyp-othermic[20oC] ischemic arrest for 2 hours with infusion of cardioplegic solution every 30 minutes throughout the ischemic period. Ten isolated hearts were studied with the oxygenated cardioplegic solution and 10 another isolated hearts with the nonoxygenated one. Mean oxygen tensions of the nonoxygenated and oxygenated cardioplegic solutions were 150mmHg and 470mmHg, respectively. Two in 10 hearts infused with the nonaxygenated cardioplegic solution were not recovered from nonworking heart due to persistent ventricular fibrillation. In comparing hem-odynamic parameters between both groups, the mean postischemic recovery[expressed as a percentage of its preischemic control value] was significantly greater with the oxygenated solution[in 10 recovered hearts] than the nonoxygenated solution[in 8 recovered hearts] [95.9$\pm$1.8% compared with 88.5$\pm$2.9% in peak aortic pressure, p<0.05, 75.7$\pm$5.2% compared with 43.5$\pm$6.5% in aortic flow, p<0.01, 75.5$\pm$4.6% compared with 54.1$\pm$5.6% in cardiac output, p<0.01, 78.3$\pm$4.6% compared with 60.3$\pm$4.6% compared with 60.3$\pm$6.2% in stroke volume, p<0.05, and 80.4$\pm$5.3% compared with 58.6$\pm$7.0% in dP/dT, p<0.05]. It is concluded that oxygenation of St. Thomas Hospital No.2 cardioplegic solution improves cardiac electrical stability and postischemic hemodynamic recovery after ischemic arrest in the isolated perfused rat heart.

• Journal of Chest Surgery
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• v.29 no.11
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• pp.1202-1206
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• 1996

Ebstein's anomaly is an unusual and a rare congenital cardiac malformation but characteristic abnormality of the development of the tricuspid valve, right atrium and ventricle. The characteristic findings are a displaced tricuspid valve with a septal leaflet spiralling into the right ventricle. The surgical correction is variable and are left unsolved problem in surgical treatment of anomaly. Between January 1988 ＆ December 1995, we experienced 11 cases of Ebstein's anomaly and associated cardiac anomalies are ASD, PFO, ASD with VSD. The typically displaced tricuspid valve leaflet was found in all cases. In the NYHA functional classification, three were in class II, seven were in class III, and one was in class IV. Nine patients were operated by tricuspid annuloplasty ＆ plication with Danielson's method and two patients were done by tricuspid valve replacement with plication, and in all cases associated anomaly was corrected. Postoperatively, five patients suffered from complication - low cardiac output syndrome, arrhythmia and wound infection. There was no operative mortality and the postoperative courses were relatively good conditions with more improvement of symptoms.

• Biomolecules & Therapeutics
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• v.6 no.2
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• pp.199-203
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• 1998

Acute hemodynamic effects of CJ-18513, a non-peptide angiotensin IIreceptor antagonist, were examined in mongrel dogs treated with high frequency ventricular pacing for one week. Rapid ventricular pacing reduced mean blood pressure (mBP), Lvdp/dt and cardiac output (CO), and increased the left ventricular end-diastolic pressure (LVEDP) and pulmonary capillary wedge pressure (PCWP). Continuous infusion of CJ-10513 at doses of 10 and 20$\mu$g/kg/min, respectively, for 30 minutes reduced mBP, LVEDP and myocardial oxygen consumption rate (MVO,) and shifted the cardiac function curve (CO-LVEDP ourve) to the left in this dog model. In conclusion, CJ-10513 decreased the preload and afterload and increased the cardiac function in dogs with pacing-induced heart failure.

• Biomolecules & Therapeutics
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• v.3 no.4
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• pp.316-321
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• 1995

All the pharmacological studies of LB17522 described here were carried out with high doses (fifteen to sixty times of the therapeutic dose) to determine an indication of potential side effects in clinical use in terms of the acute clinical signs, cardiovascular and central nervous system. LB10522 does not produce any observable clinical signs except for the symptoms such as moist eye, skin rash, slight salivation, vomitting, and slightly reduced activity. The effects of LB10522 on the hemodynamics and cardiac function of anesthetized beagle dogs are as follows; heart rates and mean arterial blood pressure had a tendency to increase mildly, which is a normal finding in anesthetized dogs. All the animals except for one showed relatively stable respiratory rates throughout the observation period. Each animal treated with LB10522 showed slight increase in the left cardiac work and left ventricular stroke work which are mainly related to corresponding increases in cardiac output. Femoral blood flow were shown to be increased in some animals treated with LB10522. The epileptogenic activities of various cephalosporins were assessed by a direct intracerebral injection of appropriate concentration of test articles. The CD$_{50}$ values (nmol) obtained from the analysis of the dose-response data are as follows; 78.2, 175.3, 156.3, and 53.5 for cefazolin, cephaloridine, ceftazidime, and LB 10522, respectively. LB10522 seems to be equipotent with cefazolin or to be three times more potent than cephaloridine and ceftazidime in causing adverse CNS stimulation. Taken into consideration all the information obtained, LB10522 is not supposed to induce much changes in the functions examined in these studies in man at therapeutic doses.s.