• The Korean Journal of Nuclear Medicine
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• v.37 no.6
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• pp.355-363
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• 2003

Purpose: Regional contractility can be calculated using the regional volume change of left ventricle measured by gated myocardial SPECT image and curve of central artery pressure obtained from radial artery pressure data. In this study, a program to obtain the regional contractility was developed, and reproducibility of regional contractility measurement was assessed. Materials and Methods: Seven patients(male:female=5:2, $58{\pm}11.9$ years) with coronary artery diseases underwent gated Tc-99m MIBI myocardial SPECT twice without delay between two scans. Regional volume change of left ventricle was estimated using CSA (Cardiac SPECT Analyzer) software developed in this study. Regional contractility was iteratively estimated from the time-elastance curve obtained using the time-pressure curve and regional time-volume curve. Reproducibility of regional contractility measurement assessed by comparing the contractility values measured twice from the same SPECT data and by comparing those measured from the pair of SPECT data obtained from a same patient. Results: Measured regional contractility was $3.36{\pm}3.38{mm}Hg/mL$ using 15-segment model, $3.16{\pm}2.25{mm}Hg/mL$ using 7-segment model, and $3.11{\pm}2.57{mm}Hg/mL$ using 5-segment model. The harmonic average of regional contractility value was almost identical to the global contractility. Correlation coefficient of regional contractility values measured twice from the same data was greater than 0.97 for all models, and two standard deviations of contractility difference on Bland Altman plot were 1.5%, 1.0%, and 0.9% for 15-, 7-, and 5-segment models, respectively. Correlation coefficient of regional contractility values measured from the pair of SPECT data obtained from a same patient was greater than 0.95 for all models, and two standard deviations on Bland Altman plot were 2.2%, 1.0%, and 1.2%. Conclusion: Regional contractility of left ventricle measured using developed software in this study was reproducible. Regional contractility of left ventricle will be a new useful index for myocardial function after analysis of the clinical data.

• Tuberculosis and Respiratory Diseases
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• v.50 no.5
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• pp.540-548
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• 2001

Backgrounds : Because ventilator-induced lung injury is partly dependent on the intensity of vascular flow, we hypothesized that hypothermia may attenuate the degree of such an injury through a reduced cardiac output. Methods : Twenty-seven male Sprague-Dawley rats were randomly assigned to normothermia ($37{\pm}1^{\circ}C$)-injurious ventilation (NT-V) group (n=10), hypothermia ($27{\pm}1^{\circ}C$)-injurious ventilation (HT-V) group (n=10), or nonventilated control group (n=7). The two thermal groups were subjected to injurious mechanical ventilation for 20 min with peak airway pressure 30 cm $H_2O$ at zero positive end-expiratory pressure, which was translated to tidal volume $54{\pm}6\;ml$ in the NT-V group and $53{\pm}4\;ml$ in the HT-V group (p>0.05). Results : Pressure-volume (P-V) curve after the injurious ventilation was almost identical to the baseline P-V curve in the HT-V group, whereas it was shifted rightward in the NT-V group. On gross inspection, the lungs of the HT-V group appeared smaller in size, and showed less hemorrhage especially at the dependent regions, than the lungs of the NT-V group. [Wet lung weight (g)/body weight (kg)] ($1.6{\pm}0.1$ vs $2.4{\pm}1.2$ ; p=0.014) and [wet lung weight/dry lung weight] ($5.0{\pm}0.1$ vs $6.1{\pm}0.8$ ; p=0.046) of the HT-V group were both lower than those of the NT-V group, while not different from those of the control group($1.4{\pm}0.4$, $4.8{\pm}0.4$, respectively). Protein concentration of the BAL fluid of the HT-V group was lower than that of the NT-V group($1,374{\pm}726\;ug/ml$ vs $3,471{\pm}1,985\;ug/ml$;p=0.003). Lactic dehydrogenase level of the BAL fluid of the HT-V group was lower than that of the NT-V group ($0.18{\pm}0.10\;unit/ml$ vs $0.43{\pm}0.22\;unit/ml$;p=0.046). Conclusions : Hypothermia attenuated pulmonary hemorrhage, permeability pulmonary edema, and alveolar cellular injuries associated with injurious mechanical ventilation, and preserved normal P-V characteristics of the lung in rats.

• Journal of Life Science
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• v.22 no.4
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• pp.532-537
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• 2012

We investigated the effect of smoking on cardiovascular responses during acute dynamic exercise. Eleven college students who had been smoking (duration of smoking: $7.45{\pm}0.90$ years; number of cigarettes per day: $17.72{\pm}1.22$) participated in this study. All subjects completed a graded exercise testing to determine the relative exercise intensity. The cardiovascular responses were measured at rest, and during mild and moderate exercise immediately, 24, and 48 hours after smoking. The same procedures were repeated during 24-h smoking withdrawal. All subjects were continuously instrumented to measure systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), stroke volume (SV), cardiac output (CO), and total vascular conductance (TVC) at rest and during exercise. The results showed that compared to the nicotine abstention, SBP, DBP, MAP, and HR were significantly higher at 24 and 48 hours after smoking ($p$<0.05), and CO was significantly higher at rest and during moderate exercise ($p$<0.05). There were no differences in SV and TVC before and after smoking. Thus, the results suggest that smoking is associated with an exaggerated sympathetic nerve activity during dynamic exercise. Consequently, smoking cessation may help reduce cardiac events, such as stroke and heart attack, during exercise.

• Tuberculosis and Respiratory Diseases
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• v.63 no.4
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• pp.346-352
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• 2007

Background: Pulmonary hypertension is one of the cardiovascular complications of in COPD. However, a diagnosis of pulmonary hypertension requires an invasive test, such as right heart catheterization. NT-proBNP is a cardiac hormone that is elevated when a cardiac volume or pressure overload is present. It was hypothesized that NT-proBNP might play a role in detecting of pulmonary hypertension in COPD patients. Method: The 31 COPD patients, who underwent all of NT-proBNP, echocardiography, and spirometry in Seoul National University Bundang Hospital during the period from November 2003 to July 2005, were retrospectively analyzed. Result: Of the 31 COPD patients, 9 patients had pulmonary hypertension. A significant positive correlation was observed between the NT-proBNP and pulmonary arterial pressure (r=0.589, p=0.002). However, there was no significant correlation observed between the $FEV_1$ and NT-proBNP and $FEV_1$ and pulmonary arterial pressure. Conclusion: NT-proBNP might indicate the presence of pulmonary hypertension in COPD patients.

• Journal of Veterinary Clinics
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• v.32 no.5
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• pp.422-425
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• 2015

This study evaluated the myocardial performance on echocardiography after the sedation/anesthesia of medetomidine (D), the combination of medetomidine and tiletamine/zolazepam (DZ), and the combination of medetomidine, tiletamine/zolazepam and tramadol (DZT) in Beagle dogs. Ten healthy adult Beagle dogs (weighing $8.6{\pm}1.0kg$) were enrolled in this study. Heart rate (HR), fractional shortening (%FS), left ventricular ejection fraction (%LVEF), stroke volume (SV), cardiac output (CO), left ventricular internal diameter in systole (LVIDs) and left ventricular internal diameter in diastole (LVIDd) using M-mode echocardiography were measured prior to anesthesia, then every 10 min for 60 min. The HR, %FS, %LVEF, SV and CO were significantly decreased during sedation/anesthesia with D, DZ and DZT combination of anesthesia. Although those anesthetic protocols provided acceptable quality of sedation/anesthesia, levels of cardiovascular suppression were substantial and persistent and thus the continuous monitoring on vital signs should be accompanied in any situation. Close attention is required for dogs with pre-existing heart diseases, when those anesthetic protocols were applied.

• Journal of Chest Surgery
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• v.21 no.3
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• pp.425-446
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• 1988

After 24 hours of preservation under 15 mmHg perfusion pressure the recovery rates of isolated canine hearts were determined. Preservation was performed in a cold room maintained at 4*C with 4 different types of perfusates bubbled with a mixture of 95% 0y and 5% CO~ using a modified perfusion unit designed in our institute. The perfusates used were as follows; Group 1: Krebs-Henseleit solution, Group 2: Krebs solution added by albumin and PGE1. Group 3: Modified Wicomb*s solution, Group 4: Modified Collin*s solution. The extent of myocardial recovery was evaluated using a modified isolated carmine perfusion model by measuring heart rate, systolic arterial pressure, left atrial pressure[LAP] and cardiac output. In addition to the above hemodynamic parameters, biochemical and enzymatic assays from perfusates and electron microscopic changes of the myocardium were also studied. The results were as follows; 1] The heart recovery rates were 41.6%, 53.4% and 108.9% in groups 1, 2 and 3, respectively, and group 3 elicited the best result[p< 0.001]. The heart beat was never recovered in group 4. 2] Recovered systolic arterial pressures[mmHg] were 63.3% in group 1, 94.9% in group 2 and 94.3% in group 3. 3] LAPs[mmHg] were 20 in group 1, 13.5 in group 2 and 11.2 in group 3, which suggested that the best myocardial preservation was elicited in group 3[p< 0.05]. 4] Cardiac output, the sum of aortic stroke volume and coronary leakage, were 69.1% in group 2, and 90.7% in group 3, but these were not statistically significant[p=0.24]. No aortic stroke output was measured in group 1 and 4. 5] The degree of myocardial edema increase was 17.5` in group 1, 24.6% in group 2, 20.9% in group 3 and 55.3% in group 4. But there were no statistical differences in each group[p= 0.08]. 6] CPK-MB[U/L] levels were increased 750% and 332%[p< 0.05], glucose levels[mg/dl] 60.5% and 78.2% and SGOT[U/L] levels 523% and 333%, in groups 2 and 3, respectively. Biochemical and enzymatic assays could not be performed in group 1 and group 4, because of poor recovery of heart beat. 7] Electron microscopic findings in the myocardium of most groups revealed slight to moderate muscle cell and mitochondrial edema. But all these findings were within the limits of reversible change. From these above results, it is suggested that modified Wicomb*s solution seems to be the most useful physiologic salt solution for preservation of the heart. We propose that after further study and improvement, our portable continuous hypothermic perfusion system will contribute to the development of a better preservation method for donor hearts for human heart transplantation.

• The Korean Journal of Emergency Medical Services
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• v.15 no.2
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• pp.101-108
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• 2011

Purpose: Cardiopulmonary resuscitation (CPR) prevents tissue necrosis of the brain and cardiac muscle in the cardiac arrest patient and requires exact skills in order to increase survival rate. Through comparison of the training effects of feedback manikin and non-feedback manikin, this study present the effective CPR device to CPR instructors. Method: This CPR course for 80 students by using Resusci Anne $SkillReporter^{TM}$ (RASR; Laerdal Medical, Stavanger, Norway) and Actar 911 $Squadron^{TM}$ (A911; Vital Signs, New Jersey, USA) held on December 22, 2009. Thirty seven students and two assistants were placed in one laboratory, there were five RASR manikins which provide the LED performance indicator, not the metronome. Forty two students and two assistants were placed in the other laboratory, there were 20 A911 manikins which don't provide any feedback indicator. Chest compression scores and ventilation compression scores obtaining from two groups were analysed statistically by using independent t-test. Results: Chest compression scores, average depth (mm) was 37.5 in RASR and 41.80 A911 (p=.004), too depth (#) was 2.8 in RASR and 19.4 A911 (p=.005), average number per min (#/min) was 64.4 in RASR and 68.2 A911 (p=.038), wrong hand position (#/min) was 10.9 in RASR and 30.8 A911 (p=.040). Four items that showed better scores in group RASR had statistically significant difference. Ventilation compression scores, percent correct (%) was 40.6 in RASR and 20.6 A911 (p<.001), number correct (#) was 4.7 in RASR and 2.1 A911 (p=.002), too fast (#) was 0.9 in RASR and 2.9 A911 (p=.003), average volume (ml) was 536.5 in RASR and 707.1 A911 (p=.011). Also, three items that showed better scores in group RASR had statistically significant difference. Conclusions: Regarding the positive effect of CPR training feedback, comparison between the real-time visual feedback manikin (RASR) and the non-feedback manikin (A911) showed that RASR had better results than A911 in chest compression except average number per min (it means that we need harder chest manikin) and ventilation. Verification of the training effect in the real world such as CPR outcomes is also necessary. A proper application of manikin in training circumstances and research on retention of CPR skills will be needed.

• Journal of Biomedical Engineering Research
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• v.19 no.4
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• pp.385-391
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• 1998

A new balancing method of atrial pressures balancing for the moving actuator total artificial heart(TAH) without an extra compliance chamber was developed. The asymmetric operation of the pendulous moving actuator have made it possible to compensate the left and right pump output difference by utilizing the interventricular air space as an internal compliance chamber in a pump housing. Furthermore, the balancing performance between left and right pump outputs is increased through the improvement of the flexibility of part of the polyurethane housing. However, the increase of the flexibility of the pump housing causes a little loss of the cardiac output due to the reduction of active filling property. In this paper., a good condition between the balance and pump output performance is evaluated by adjusting the air volume in the interventricular space through a series of in vitro experiments. This new pump was implanted in a sheep weighting 63kg, and it survived for 3 days and the average cardiac output during postoperative days was about 4.2 L/mim with the atrial pressures under 15 mmHg.

• Biomedical Science Letters
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• v.2 no.1
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• pp.71-90
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• 1996

There is considerable current interest in the effect of regular vigorous exercise and in particular endurance-running as a possible measure in improving myocardial function. Some data indicate that the aging heart may actually suffer from vigorous endurance exercise. On the contrary appropriate exercise in aged animals improves myocardial function and aerobic energy metabolism. So far there is relatively little data to indicate that endurance exercise is in fact beneficial in improving myocardial function or damaging to heart of aged animals. The present investigation aimed to study the possible effect of a long range treadmill training program on the heart in aging rats. Male rats aged 3, 10, and 20 months were divided at random into a control (sedentary) and an exercise group. The training group was exercised for 5 days a week on an automated treadmill for 20minutes at 18m/min over a period of 5 months. The exercise regimen of our experiments did not cause any significant changes in the tissues and ultrastructural as com-pared with sedentary age-matched control. Tissues and ultrastructures of myocardial cells in trained group aged 8 months are intact and well organized as well as sedentary control group. Age associated tissue and ultrastructural changes of trained group aged 15 months included : an increase in transformed mitochondria, vacuoles, lysosomes, lipid droplets and early lipofuscin. But the trained heart did not show significant difference in tissue and ultrastructural properties from those of sedentary controls. Endurance-trained group aged 25 months showed significant qualitative tissue and ultrastructural difference as compared with age-matched controls. In addition to those found in 25 months control group, focal necrosis, myofibril fraying, hypercontraction band, seperation of intercalated discs, degenerating nucleus and infiltration of collagenous fiber into myocyte were noted in trained 25 months group. The stereological examination of the mi-crographs disclosed no significant difference in the myoflbril, mitochondrion, sarcotubule and in-terstitium volume density and surface density of mitochondrial cristae and numerical density of mitochondria between trained and control group aged 8 and 15 months. In the trained 25 months group, significant increase in volume density of interstitium, lipofucsin granule were shown as compared to untrained age-matched control. On the other hand, significant decrease in mitochondrion volume density was shown. The myofibril volume density did not differ between trained and control group although trained group showed slight increase. From the data obtained a reduced mitochondria/myofibrils ratio was found in trained rat heart aged 25 months and there was no difference between trained and control rat aged 15 months. But a slight but not significant increase was found in the trained group aged 8 months as compared with same age control group. Such increase in the ratio in young animals is considered to be of great importance to cardiac pumping and adaptability. Whereas such adaptations don't seem to occur in aged heart muscle. This study proposed that repeated endurance exercise do not cause any significant qualitative and quantitative ultrastructural change of heart muscle in young(3months) and adult (10months) suggesting that the heart is able to adapt to the exercise. On the contrary, the repeated endurance exercise stress may actually induce degenerative changes in the aged heart muscle(20months).

• Clinical and Experimental Pediatrics
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• v.49 no.11
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• pp.1194-1201
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• 2006

Purpose : The comatose mentality can be catastrophic, especially if the condition is severe or the duration is prolonged. Therefore, delayed diagnosis can result in a poor outcome or death. The best radiologic modality to differentiate from cerebral lesions in patients suffering from cerebral diseases is magnetic resonance imaging (MRI) rather than computed tomography (CT). Special apparatuses with metal materials such as ventilators, and cardiac pacemakers belonging to patients cannot be located in the magnetic field. We aimed to exhibit the possibility of examining MRI, maintaining ventilation at a relative long distance by means of modified $Ambu^{(R)}$. Methods : Self-inflating bags as a sort of a manual ventilator, connected with relatively long extension tubes instead of mechanical ventilators, were adopted to obtain MRI. PVC (polyvinyl chloride) extension tubes had different lengths and diameters. Lengths were 1, 2, and 3 cm and diameters were 15, and 25 mm. The work of breathing and expiratory changes of expiratory tidal volume (TVe), minute volume of expiration (MVe), peak inspiratory pressure (PIP) were measured by use of the mechanical ventilator, $Servoi^{(R)}$, as the alteration of TVi (inspiratory tidal volume), extension tube lengths and diameters with other values fixed. Results : Measured TVe and MVe by ventilator were the same values with control at every TVi, regardless of extension tube lengths and diameters, but PIP were increased with the rise of TVi, tube lengths, with decline of tube diameters, these were statistically significant. Conclusion : MRI examination can be carried out with a self-inflating bag connected with an extension tube at a long distance in patients who need artificial ventilation.