• Progress in Medical Physics
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• v.10 no.3
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• pp.159-168
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• 1999

Cardiac disease is one of the leading causes of death in Korea. In quantitative analysis of cardiac function and morphological information by three-dimensional reconstruction of magnetic resonance images, left ventricle provides an important role functionally and physiologically. However, existing procedures mostly rely on the extensive human interaction and are seldom evaluated on clinical applications. In this study, we developed a system which could perform automatic extraction of enpicardial and endocardial contour and analysis of cardiac function to evaluate reliability and stability of each system comparing with the result of ARGUS system offered 1.5T Siemens MRI system and manual method performed by clinicians. For various aspects, we investigated reliability of each system by compared with left ventricular contour, end-diastolic volume (EDV), end-systolic volume (ESV), stock volume (SV), ejection fraction (EF), cardiac output (CO) and wall thickness (WT). When comparing with manual method, extracted results of developed process using minimum error threshold (MET) method that automatically extracts contour from cardiac MR images and ARGUS system were demonstrated as successful rate 90% of the contour extraction. When calculating cardiac function parameters using MET and comparing with using correlation coefficients analysis method, the process extracts endocardial and epicardial contour using MET, values from automatic and ARGUS method agreed with manual values within :t 3% average error. It was successfully demonstrated that automatic method using threshold technique could provide high potential for assessing of each parameters with relatively high reliability compared with manual method. In this study, the method developed in this study could reduce processing time compared with ARGUS and manual method due to a simple threshold technique. This method is useful for diagnosis of cardiac disease, simulating physiological function and amount of blood flow of left ventricle. In addition, this method could be valuable in developing automatic systems in order to apply to other deformable image models.

• PNF and Movement
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• v.16 no.2
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• pp.187-194
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• 2018

Purpose: This study aimed to assess the effect of rowing ergometer training on the aerobic capacity and strength of male high school students over a 12-week period. Methods: Fourteen high school students volunteered to participate in the study. The subjects were divided into two groups: seven subjects in the experimental group and seven in the control group. The subjects in the experimental group performed rowing ergometer training for 75 min per session at three days a week for 12 weeks. The exercise intensity set the maximum heart rate (HRmax) from 40% to 80%. Aerobic capacity was measured by ventilation, cardiac output, and oxygen intake per body weight. Strength was measured by grip strength and back strength before and after training. Results: A significantly increased ventilation (p=0.01), cardiac output (p=0.01), and oxygen intake per body weight (p=0.00) were found in the experimental group. A significantly increased grip strength in the right and left hands (p=0.00, 0.00) and back strength (p=0.04) were observed in the experimental group. Conclusion: Rowing ergometer training can be an effective combined exercise for aerobic capacity and strength of high school students.

• Journal of Chest Surgery
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• v.16 no.1
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• pp.18-29
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• 1983

Thirty-two patients with a cyanotic cardiac malformations having more complex intracardiac defects than ones in a tetralogy of Fallot underwent complete intracardiac repairs in a-full-year period from July 1981 to June 1982. Twenty-two patients [68.8%] died within 30 days after surgery: Transposition of the great arteries, seven of 10 patients; Double-outlet right ventricle, four of 6 patients; Tricuspid atresia, four of 6 patients; Single ventricle, all of 4 patients; Pulmonary atresia, two of 3 patients; Double-outlet left ventricle, none of 2 patients; and Truncus arteriosus, one of a single patient. All deaths occurred with a low cardiac output syndrome or a failed off-bypass, and they were almost always accompanied with other grave postoperative complications. The complex intracardiac anatomy itself was one of the risk factors by making a complete intracardiac repair of the defects difficult in a small heart. The reconstruction of the right ventricular outflow carried a difficulty in balancing an adequate relief of the obstruction with an avoidance of making too much pulmonary valvular insufficiency as well. On the other hand, the presence of an elevated pulmonary arterial pressure and a high pulmonary vascular resistance was also the factors affecting the postoperative surviv als. The importance of detailed knowledge of intracardiac anatomy and hemodynamics from the careful preoperative evaluation of the patient was discussed along with the necessity of technical refinement of the correction.

• 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.

• The Korean Journal of Nuclear Medicine
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• v.4 no.2
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• pp.11-27
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• 1970

Cardiac output, plasma volume and renal plasma flow were determined to evaluate hemodynamic changes in 29 patients with cirrhosis of the liver. The results obtained were as follows. 1. The mean plasma volume was 3793+895ml and it was significantly higher than the normal controls. The mean blood volume ($5266{\pm}1222ml$) and blood volume per kg body weight ($95.7{\pm}23.41ml$) were also increased significantly. The mean plasma volume per kg body weight ($69.1{\pm}19.1ml$) showed increased tendency and the mean difference between blood volume and plasma volume per kg body weight ($26.4{\pm}7.05ml$) was in lower limit of normal range. 2. The mean cardiac output was $7708{\pm}2652ml/min$ and it was significantly increased. The mean cardiac index ($4924{\pm}1998ml/min/M^2$), stroke volume ($96.2{\pm}34.2ml/beat$), stroke index ($62.3{\pm}27.34ml/M^2$) and fractional cardiac index ($1.54{\pm}0.577$) were also increased significantly. The mean total -peripheral resistance was $1664{\pm}753.8\;dynes\;sec\;cm^{-5}M^2$ and it was significantly lower than the normal controls. 3. The mean renal plasma flow was $537{\pm}146.8ml/min/1.73M^2$ and it was normal to decreased tendency. The mean endogenous creatinine clearance ($66.7{\pm}23.0ml/min/1.73M^2$) was significantly decreased. Filtration fraction was variable, but it was slightly lower than normal in most cases. The mean renal fraction of cardiac output ($11.4{\pm}6.27%$) was relatively decreased. 4. Although renal plasma flow was normal or decreased in general, it was definitely diminished in patients with creatinine clearance less than $60ml/min/1.73M^2$, resistant ascites, and signs of azotemia (elevated BUN and serum creatinine). 5. Diminished glomrular filtration rate with low filtration fraction and decreased renal fraction of cardiac output observed strongly supported increased renal afferent arteriolar resistance. 6. Renal circulatory impairment preceded azotemia or oroliguria in cirrhosis. 7. Clinical findigns and liver function were not correlated with hemodynamic changes, except for esophageal varices associated with high cardiac output obsedved. 8. No definite correlation of renal hemodynamics with plasma volume or cardiac output was found.

• Journal of Chest Surgery
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• v.17 no.4
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• pp.644-656
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• 1984

In Tetralogy of Fallot, the most common congenital cyanotic heart disease, the mortality is decreasing continuously with adequate type and timing of operation. At S.N.U.H., 195 patients were operated from January 1982 to December 1983 and 176 patients among them were analysed in the view of pre-operative pulmonary arterial condition measured by cardiac cineangiogram. The most common associated anomaly was PFO and ASD and they did not affect the postoperative course and mortality. The overall mortality rate was 8.5% in 1982 and 6.8% in 1983 but under 2 years of age, the mortality rate was relatively high as 25% in 1982 and 16.7% in 1983, and when transannular patch widening of Right Ventricular Outflow Tract was used, the mortality rate was 12.5% in 1982 and 27.3% in 1983. Preoperative angiographic measurements of the pulmonary arterial status for prediction of the ratio between the Left Ventricular and Right Ventricular peak systolic pressure were calculated retrospectively according to the Blackstones formula, and the predicted value of PRV/LV greater than 0.6 carried apparently high complication and mortality rate as 16.6% M.R. in 1982 and 11.1 % in 1983. Among postoperative complications, c-RBBB occurred most frequently about 50% but did not influenced to mortality, Low Cardiac Output Syndrome was developed in about 40%. If we select the patient who should have the staged operation including shunt operation and choose the type of RVOT relief, we expect the improvement of postoperative clinical results.

• Childhood Kidney Diseases
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• v.21 no.1
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• pp.26-30
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• 2017

Newborn infants with huge and highly vascular sacrococcygeal teratoma (SCT) are frequently subjected to renal hypoperfusion secondary to high-output cardiac failure. Any underlying renal dysfunction is a significant risk factor for the development of contrast-induced nephropathy (CIN). However, reports on CIN in infants are rare. I report here a case of a premature infant born at 28 weeks and 3 days of gestation with a huge SCT who survived preoperative embolization and surgical resection but presented with persistent non-oliguric renal failure that was suggestive of CIN. During radiological intervention, a contrast medium had been administered at about 10 times the manufacturer-recommended dose for pediatric patients. Despite hemodynamic stabilization and normalization of urine output immediately following surgery, the patient's serum creatinine and cystatin-C levels did not return to baseline until 4 months after birth. No signs of reflux nephropathy were observed in follow-up imaging studies. Dosing guidelines for the use of a contrast medium in radiological interventions should be provided for infants or young patients.

• Journal of Chest Surgery
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• v.16 no.4
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• pp.498-505
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• 1983

It has been over 20 years since successful operations of Cardiac valves at the Department of Thoracic and Cardiovascular surgery, college of medicine, Yonsei University. About six hundreds of patients with severely symptomatic valvular heart disease have had valve operations with complete loss or sharp decrease in their cardiac symptoms since 1956. As the number of cardiac patient increases, reoperation on valves assumes greater importance. To define the group of patients undergoing reoperations on valves and the factors influencing their survival, we have reviewed our experiences of the reoperation on valves at the Yonsei University, Severance Hospital. This is a report of 29 cases which was undergone secondary or more surgery for valvular heart disease from 1966 to 1983. The primary operations includes 159 cases of open heart surgery from 1966 to 1975 and 476 cases from 1976 to march, 1983. The secondary operations are classified into groups of secondary valvuloplasty or valvotomy [8 cases], prosthetic valve replacement following valvuloplasty or valvotomy [14 cases] and prosthetic valve rereplacement [2 case] for such as calcification, degeneration and perforation of the cusps and paravalvular leakage, of the bioprosthetic valves. The leading indication for reoperation of mitral valve was restenosis or stenoinsufficiency, The indications of aortic valve replacement was active bacterial endocarditis, medically uncontrollable prosthetic endocarditis or paravalvular leakage. Overall death rate of the reoperation was 17.4% [5 death among the 29 patients] and the leading causes of death were myocardial failure, arrhythmia, cerebral embolism, acute renal failure due to low output syndrome. And it was followed by sepsis associated with active prosthetic endocarditis. The death rate of reoperation was 4.3% in the elective cases except urgent cases and the death rate of overall cardiac valve except reoperation cases was 4.1% in the last two years. Although the general mortality of reoperation was high, both mortality rates were comparable except emergency cases due to urgent preoperative patient’s condition.

• Proceedings of the KOSOMBE Conference
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• v.1992 no.05
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• pp.27-47
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• 1992

Engineers have developed new instruments that aid in diagnosis and therapy Ultrasonic imaging has provided a nondamaging method of imaging internal organs. A complex transducer emits ultrasonic waves at many angles and reconstructs a map of internal anatomy and also velocities of blood in vessels. Fast computed tomography permits reconstruction of the 3-dimensional anatomy and perfusion of the heart at 20-Hz rates. Positron emission tomography uses certain isotopes that produce positrons that react with electrons to simultaneously emit two gamma rays in opposite directions. It locates the region of origin by using a ring of discrete scintillation detectors, each in electronic coincidence with an opposing detector. In magnetic resonance imaging, the patient is placed in a very strong magnetic field. The precessing of the hydrogen atoms is perturbed by an interrogating field to yield two-dimensional images of soft tissue having exceptional clarity. As an alternative to radiology image processing, film archiving, and retrieval, picture archiving and communication systems (PACS) are being implemented. Images from computed radiography, magnetic resonance imaging (MRI), nuclear medicine, and ultrasound are digitized, transmitted, and stored in computers for retrieval at distributed work stations. In electrical impedance tomography, electrodes are placed around the thorax. 50-kHz current is injected between two electrodes and voltages are measured on all other electrodes. A computer processes the data to yield an image of the resistivity of a 2-dimensional slice of the thorax. During fetal monitoring, a corkscrew electrode is screwed into the fetal scalp to measure the fetal electrocardiogram. Correlations with uterine contractions yield information on the status of the fetus during delivery To measure cardiac output by thermodilution, cold saline is injected into the right atrium. A thermistor in the right pulmonary artery yields temperature measurements, from which we can calculate cardiac output. In impedance cardiography, we measure the changes in electrical impedance as the heart ejects blood into the arteries. Motion artifacts are large, so signal averaging is useful during monitoring. An intraarterial blood gas monitoring system permits monitoring in real time. Light is sent down optical fibers inserted into the radial artery, where it is absorbed by dyes, which reemit the light at a different wavelength. The emitted light travels up optical fibers where an external instrument determines O2, CO2, and pH. Therapeutic devices include the electrosurgical unit. A high-frequency electric arc is drawn between the knife and the tissue. The arc cuts and the heat coagulates, thus preventing blood loss. Hyperthermia has demonstrated antitumor effects in patients in whom all conventional modes of therapy have failed. Methods of raising tumor temperature include focused ultrasound, radio-frequency power through needles, or microwaves. When the heart stops pumping, we use the defibrillator to restore normal pumping. A brief, high-current pulse through the heart synchronizes all cardiac fibers to restore normal rhythm. When the cardiac rhythm is too slow, we implant the cardiac pacemaker. An electrode within the heart stimulates the cardiac muscle to contract at the normal rate. When the cardiac valves are narrowed or leak, we implant an artificial valve. Silicone rubber and Teflon are used for biocompatibility. Artificial hearts powered by pneumatic hoses have been implanted in humans. However, the quality of life gradually degrades, and death ensues. When kidney stones develop, lithotripsy is used. A spark creates a pressure wave, which is focused on the stone and fragments it. The pieces pass out normally. When kidneys fail, the blood is cleansed during hemodialysis. Urea passes through a porous membrane to a dialysate bath to lower its concentration in the blood. The blind are able to read by scanning the Optacon with their fingertips. A camera scans letters and converts them to an array of vibrating pins. The deaf are able to hear using a cochlear implant. A microphone detects sound and divides it into frequency bands. 22 electrodes within the cochlea stimulate the acoustic the acoustic nerve to provide sound patterns. For those who have lost muscle function in the limbs, researchers are implanting electrodes to stimulate the muscle. Sensors in the legs and arms feed back signals to a computer that coordinates the stimulators to provide limb motion. For those with high spinal cord injury, a puff and sip switch can control a computer and permit the disabled person operate the computer and communicate with the outside world.

• Journal of Biomedical Engineering Research
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• v.33 no.1
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• pp.39-46
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• 2012

Electrical impedance tomography(EIT) can produce functional images with conductivity distributions associated with physiological events such as cardiac and respiratory cycles. EIT has been proposed as a clinical imaging tool for the detection of stroke and breast cancer, pulmonary function monitoring, cardiac imaging and other clinical applications. However EIT still suffers from technical challenges such as the electrode interface, hardware limitations, lack of animal or human trials, and interpretation of conductivity variations in reconstructed images. We improved the KHU Mark2 EIT system by introducing an EIT electrode interface consisting of nano-web fabric electrodes and by adding a synchronized biosignal measurement system for gated conductivity imaging. ECG and respiration signals are collected to analyze the relationship between the changes in conductivity images and cardiac activity or respiration. The biosignal measurement system provides a trigger to the EIT system to commence imaging and the EIT system produces an output trigger. This EIT acquisition time trigger signal will also allow us to operate the EIT system synchronously with other clinical devices. This type of biosignal gated conductivity imaging enables capture of fast cardiac events and may also improve images and the signal-to-noise ratio (SNR) by using signal averaging methods at the same point in cardiac or respiration cycles. As an example we monitored the beat by beat cardiac-related change of conductivity in the EIT images obtained at a common state over multiple respiration cycles. We showed that the gated conductivity imaging method reveals cardiac perfusion changes in the heart region of the EIT images on a canine animal model. These changes appear to have the expected timing relationship to the ECG and ventilator settings that were used to control respiration. As EIT is radiation free and displays high timing resolution its ability to reveal perfusion changes may be of use in intensive care units for continuous monitoring of cardiopulmonary function.