• Journal of Chest Surgery
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• v.40 no.1 s.270
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• pp.45-51
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• 2007

Background: Although echocardiography is usually used for quantitative assessment of left ventricular function, the recently developed 16-slice multidetector computed tomography (MDCT) is not only capable of evaluating the coronary arteries but also left ventricular function. Therefore, the objective of our study was to compare the values of left ventricular function quantified by MDCT to those by echocardiography for evaluation of its regards to clinical applications. Material and Method: From 49 patients who underwent MDCT in our hospital from November 1, 2003 to January 31, 2005, we enrolled 20 patients who underwent echocardiography during the same period for this study. Left ventricular end-diastolic volume index (LVEDVI), left ventricular end-systolic volume index (LVESVI), stroke volume index (SVI), left ventricular mass index (LVMI), and ejection fraction (EF) were analyzed. Result: Average LVEDVI ($80.86{\pm}34.69mL$ for MDCT vs $60.23{\pm}29.06mL$ for Echocardiography, p<0.01), average LVESVI ($37.96{\pm}24.52mL$ for MDCT vs $25.68{\pm}16.57mL$ for Echocardiography, p<0.01), average SVI ($42.90{\pm}15.86mL$ for MDCT vs $34.54{\pm}17.94mL$ for Echocardiography, p<0.01), average LVMI ($72.14{\pm}25.35mL$ for MDCT vs $130.35{\pm}53.10mL$ for Echocardiography, p<0.01), and average EF ($55.63{\pm}12.91mL$ for MOCT vs $59.95{\pm}12.75ml$ for Echocardiography, p<0.05) showed significant difference between both groups. Average LVEDVI, average LVESVI, and average SVI were higher in MDCT, and average LVMI and average EF were higher in echocardiogram. Comparing correlation for each parameters between both groups, LVEDVI $(r^2=0.74,\;p<0.0001)$, LVESVI $(r^2=0.69,\;p<0.0001)$ and SVI $(r^2=0.55,\;p<0.0001)$ showed high relevance, LVMI $(r^2=0.84,\;p<0.0001)$ showed very high relevance, and $EF (r^2=0.45,\;p=0.0002)$ showed relatively high relevance. Conclusion: Quantitative assessment of left ventricular volume and function using 16-slice MDCT showed high relevance compared with echocardiography, therefore may be a feasible assessment method. However, because the average of each parameters showed significant difference, the absolute values between both studies may not be appropriate for clinical applications. Furthermore, considering the future development of MDCT, we expect to be able to easily evaluate the assessment of coronary artery stenosis along with left ventricular function in coronary artery disease patients.

• Journal of Veterinary Clinics
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• v.26 no.4
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• pp.317-323
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• 2009

This study was performed to evaluate the effect of intravenous administration of glycopyrrolate on cardiovascular and respiratory system in dogs given intravenous medetomidine (20 ${\mu}g$/kg) and intramuscular midazolam (0.3 mg/kg) (MM). Prior to administration of MM, glycopyrrolate was administered intravenously at doses of 5 ${\mu}g$/kg (Gly-5), 10 ${\mu}g$/kg (Gly-10) or 20 ${\mu}g$/kg (Gly-20), respectively. For the control group saline was administered intravenously. In the cardiovascular system, HR, BP, RAP, PAWP, CI, SI, SVR, and PVR were measured. RR, $V_T$, $P_{ETCO2}$, and arterial blood gas analysis were measured for respiratory system. Although rapid and satisfied depth of sedation was obtained by MM, life-threatening bradycardia, the outstanding side-effect on cardiovascular system in dogs were observed. This combination also decreased CO and increased SVR, RAP, and PAWP significantly. The bradycardia could be prevented in all the glycopyrrolate treated groups, but tachycardia was observed in Gly-10 and Gly-20 groups. Significant increases in blood pressure were shown in glycopyrrolate treated groups. Also, tachycardia depends on dose of glycopyrrolate, compensating the CO. However, these were not fully reserved. In conclusion, MM combination could induce rapid and satisfied depth of sedation but was not the suitable method for the deep sedation of dogs with cardiovascular or circulatory problems.

• Journal of Yeungnam Medical Science
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• v.16 no.2
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• pp.181-192
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• 1999

Background: Nitric oxide, a vasodilator synthesized from L-arginine by vascular endothelial cells, accounts for the biological activity of endothelium derived relaxing factor. Previous studies demonstrated that nitric oxide inhibitor, $N^{\omega}$-Nitro-L-Arginine(NNA) diminished the hyperdynamic splanchnic and systemic circulation in portal hypertensive rats The present study was done to determine the role of nitric oxide in the development of hyperdynamic circulations in the prehepatic portal hypertensive rat model produced by partial portal vein ligation. Methods: The portal hypertensive rats were divided into water ingestion group and NNA ingestion group. After partial portal vein ligation, NNA ingestion group and water ingestion group received NNA 1mg/kg/day and plain water through the mouth for 14 days, respectively. Cardiac output, mean arterial pressure, organ blood flow and porto-systemic shunting were measured by radioisotope labeled microsphere methods. Vascular resistances were calculated by standard equation. Results: There were significant decreases in mean arterial pressure, increases in cardiac output and cardiac index, and decreases in total systemic and splanchnic vascular resistance in portal hypertensive rats compared to normal control group (p<0.01). Compared to the water ingestion group, significantly increased mean arterial pressure with decreased cardiac output and cardiac index were developed in the NNA ingestion group. Total systemic and splanchnic vascular resistance were significantly increased in the NNA ingestion group compared to water ingestion group (p<0.05). But, there was no significant difference in portal pressure between the two groups. Conclusion: The hemodynamic results of this study indicate that hyperdynamic circulation in prehepatic portal hypertensive rat mode1 was attenuated by ingestion of NNA. Nitric oxide may play an important role in the development of hyperdynamic circulation with splanchnic vasodilation in chronic portal hypertension.

• Tuberculosis and Respiratory Diseases
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• v.48 no.3
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• pp.347-356
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• 2000

Background : Patients with obstructive sleep apnea syndrome are known to have high long-term mortality compared to healthy subjects because of their cardiovascular dysfunction. The observation of hemodynamic changes by obstructive apneas is helpful when attempting to understand the pathophysiological mechanism of the development of cardiovascular dysfunction in those patients. Therefore, we studied the changes in cardiovascular function with an animal model and tried to obtain the basic data for an ideal experimental model (this phrase is unclear), a requirement for a more advanced study. Methods : Sixteen anesthetized dogs with ${\alpha}$-chloralose delete were divided into two groups : 8 dogs of room air breathing group and 8 dogs of oxygen breathing group. We measured $PaO_2$, $PaCO_2$, heart rate, cardiac output, mean femoral artery pressure, and mean pulmonary artery pressure at specified times during the apnea-breathing cycle before endotracheal tube occlusion (baseline), 25 seconds after endotracheal tube occlusion (apneic period), 10 seconds (early phase of postapneic period, EPA) and 25 seconds (late phase of postapneic period, LPA) after spontaneous breathing. Results : In room air breathing group, the heart rate significantly decreased during the apneic period compared to that at baseline (P<0.01) and increased at EPA and LPA compared to that during the apneic period (P<0.01). But, the heart rate showed no significant changes during apneic and postapneic periods in the oxygen breathing group. Cardiac output tended to decrease during apneic period compared to that at baseline, but was statistically significant. Cardiac output significantly decreased at LP A compared to at baseline (P<0.01). Mean femoral artery pressure was significantly decreased at during apneic period compared to that at baseline (P<0.05). Conclusion : Through this experiment, we were partially able to understand the changes of cardiovascular function indirectly, but delete new experimental animal model displaying physiological mechanism close to natural sleep should be established, and the advanced study in the changes of cardiovascular function and their causes should be continued.

• Tuberculosis and Respiratory Diseases
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• v.42 no.6
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• pp.913-922
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• 1995

Background: When we define the pressure of pulmonary vasculature in which a recruitment of blood flow occurs as $P_I$ and the proportion of change in pulmonary artery to that in cardiac output as IR and then we compare PI and IR with pulmonary vascular resistance, we would find some problems in pulmonary vascular resistance. In other words, it is the theory that, IR should be increased mainly in pulmonary embolism in which decreases the cross sectional area of pulmonary vasculature. But there are many contradictory reports resulted from various researches and the fact is known widely that any difference exists between PVR and PI, IR. For this reason, the purpose of this study is to observe how PI and IR change at the time of the outbreak and during treatment of the pulmonary embolism, and to find out the meaning of these new indicators and the difference from the pulmonary vascular resistance used generally when we subdivide the pulmonary vascular resistance into PI and IR. Method: After making AV fistula in experimental dog, we controlled cardiac output at the intervals of 15 minute in case of three kinds(all AV fistula are obstructed, only one of fistula is open and all of fistula is open), and after evoking massive pulmonary embolism with radioactive autologous blood clots, we measured the mean pulmonary artery pressure, and calculated PI and IR. We observed the pattern of change in PI and IR, without giving the control group any specific treatment and with injecting intravenously rtPA in the Group 1 and Group 2 at the dose of 1mg per kg, for 15 minutes fot the former and 3 hours for the latter. Result: 1) Pulmonary vascular resistance showed a change similar to that of pulmonary artery pressure and in all three group, PVR increased significantly, but group 1 and group 2 showed tendency that PVR keeps on decreasing after treatment, and the rate of decrease in group 1 is more rapid than group 2 significantly. 2) Both intersection(PI) and degree(IR) are proved statistically significant, in view of the straight line relationship between cardiac output and pulmonary artery pressure, calculated by minimal regression method. 3) PI changed similarly to pulmonary vascular resistance, while in the IR which is theoretically more similar to PVR, there was no significant difference or change after rtPA infusion. Conclusion: In the pulmonary embolism, Both change in IR which means real resistance of pulmonary vasculature and PI which was developed due to secondary vasoconstriction by pulmonary embolism are reflected same time.

• Journal of Biomedical Engineering Research
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• v.25 no.6
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• pp.565-573
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• 2004

In this paper, we proposed a heart activity control model for simulation of the aortic sinus baroreceptor, which was the most representative baroreceptor sensing the variance of pressure in the cardiovascular system. And then, the heart activity control model composed electric circuit model of the cardiovascular system with baroreflex control and time delay sub-model to observe the effect of time delay in heart period and stroke volume under the regulation of baroreflex in the aortic sinus. The mechanism of time delay in the heart activity baroreflex control model is as follows. A control function is conduct sensing pressure information in the aortic sinus baroreceptor to transmit the efferent nerve through central nervous system. As simulation results of the proposed model, we observed three patterns of the cardiovascular system variability by the time delay. First of all, if the time delay over 2.5 second, aortic pressure and stroke volume and heart rate was observed non-periodically and irregularly. However, if the time delay from 0.1 second to 0.25 second, the regular oscillation was observed. And then, if time delay under 0.1 second, then heart rate and aortic pressure-heart rate trajectory were maintained in stable state.

• Journal of Biomedical Engineering Research
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• v.19 no.1
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• pp.47-52
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• 1998

To develop the supplementary heart valve which could reduce the complications of prosthetic heart valve, in vitro experiments were performed to analyze the movement of the supplement valves from the view point of the flow dynamics and leaflet dynamics. The autologous pericardium was attached to deficient portion of the porcine valve which was dissected completely and partially. The pericardium was treated by buffered glutaraldehyde solution in the preshaped mould to preserve the shape of the leaflet. The function of the valves were evaluated in the mock circulatory system and three sets of experiment were performed. The instantaneous motion of the leaflet was pictured by the 35mm camera and the pressure drop through the valve and cardiac output were measured. The supplementary valve which was replaced completely performed better thatn the valve replaced partially. In vitro experiments showed that the supplementary valve which was replaced completely performed better than the valve replaced partially. In vitro experiments showed that the supplementary valve could undertake the prosthetic heart valve in clinic.

• The Korean Journal of Nuclear Medicine
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• v.4 no.2
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• pp.73-78
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• 1970

Repeated measurements of cardiac output in the same 11 normal individuals were done with $^{131}I-Hippuran$ and RIHSA. Following results were obtained; 1) The cardiac output measured with RIHSA was $6750{\pm}866ml/min$. 2) The cardiac output measured with $^{131}I-Hippuran$ was $5940{\pm}764ml/min$. 3) The relative value of cardiac output measured with $^{131}I-Hippuran$ to that measured with RIHSA was 88 percent, and a statistical significance was found present in this difference.

• Journal of Chest Surgery
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• v.34 no.2
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• pp.111-117
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• 2001

배경: 심근 수축력과 더불어 전신저항은 개심술 후 적절한 심박출량을 유지하기 위한 매우 중요한 요인이다. 후부하의 변화를 비관혈적으로 평가할 수 있는지 알아 보고자 대동맥 혈류파형의 변화를 관찰하였다. 대상 및 방법: 개흉한 8마리의 잡견에서 연속파형 Doppler 심초음파를 이용하여 nitroprusside 단독 또는 epinephrine과의 병합투여 잔후로 상행 대동맥 혈류를 측정하였다. 결과: Nitroprusside의 투여로 동맥압과 전신저항은 약물의 투여량에 비례하여 감소함으로써(p<0.05 vs 기준치), 대동맥 혈류파형의 최고속도, 평균가속 및 분거리(속도시간적분$\times$심박동수)는 증가하였고, 가속시간은 짧아졌으며(p<0.05 vs 기준치), 가속시간/박출시간의 비는 변화가 없었다. Nitroprusside 투여로 인한 전신저항의 변화는 속도시간적분이나 Doppler 시간간격 지표보다는 최고속도(r=0.60, p=0.001)와 평균가속(r=0.52, p=0.003)과 상관관계가 있었다. Epinephrine과의 병합투여로 전신저항이 증가하지 않는 한 nitroprusside 단독투여에 비해서 최고속도, 평균가속 및 속도시간적분이 더 크게 증가했으나, 전신저항이 증가되면 이 Doppler 지표들은 감소하는 경향을 보였다. 결론: Doppler 심초음파를 이용하여 상행 대동맥 혈류파형의 최고속도와 평균가속을 연속적으로 측정함으로써 후부하의 변화를 비관혈적으로 평가할 수 있으리라 생각된다.

• Journal of Biomedical Engineering Research
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• v.14 no.1
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• pp.41-50
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• 1993

This paper proposes an adaptive technique for the cardiac output regulation of a pendulum type electromechanical TAH. This techinque, which consists of two RLSE's and two PASTC' 5, performs Its controllability over the TAIB so that the m(RAP) and m(LAP) values re- main close to their desired values under she assumption that the variation of m(RAP) and m (LAP) are dominated by the variation of C.0. and the difference between the left and right ventricular output, respectively. To evaluate the performance of the proposed control system, a simulation is performed by using a human model which contains physiologic, drug and treatment, artificial heart and noise models. As a result, dual adaptive controller showed that abnormal m(LAP) and m(RAP) could be recovered to the normal range within 10minute and maintained desired value in steady state. The operation of this controller prored to be robust in spite of the rapid variation of human status.