• Journal of the Optical Society of Korea
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• v.10 no.1
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• pp.42-47
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• 2006

M-mode imaging of the in vivo murine myocardium using optical coherence tomography (OCT) is described. Application of conventional techniques (e.g. MRI, Ultrasound imaging) for imaging the murine myocardium is problematic because the wall thickness is less than 1.5 mm (20 g mouse), and the heart rate can be as high as six hundred beats per minute. To acquire a real-time image of the murine myocardium, OCT can provide sufficient spatial resolution ($10{\mu}m$) and imaging speed (1000 A-scans/s). Strong light scattering by blood in the heart causes significant light attenuation, which makes delineation of the endocardium-chamber boundary problematic. To measure the thickness change of the myocardium during one heart beat cycle, a myocardium edge detection algorithm is developed and demonstrated.

• Journal of Chest Surgery
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• v.13 no.4
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• pp.321-337
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• 1980

The increasing use of cardioplegic solution for the reduction of ischemic tissue injury requires that all cardiplegic solution be carefully assessed for any protective or damaging properties. This study describes functional, enzymatic and structural assessment of the efficiency of three cardioplegic solutions (Young & GIK, Bretschneider, and $K^{+}$ Albumin solution) in a Modified Isolated Rat Heart Model of cardiopulmonary bypass and ischemic arrest. Isolated rat heart were subjected to a 2-minute period of coronary infusion with a cold cardioplegic or a noncardioplegic solution immediately before and also at the midpoint of a 60-minute period of hypothermic ($10{\pm}1$. C) ischemic cardiac arrest. The results of this study were as follow: 1. Spontaneous heart beat after ischemic arrest occured 16 seconds later after Langendorff reperfusion in the Young & GIK group (n=6), and 40 second later in the Bretschneider group (n=6) and 6 minute later in the $K^{+}$ Albumin group (n=6), and 16 minute later in the control group (non-cardioplegia). A good recovery state of spontaneous heart beat was shown in the Young & GIK and Bretschneider groups. 2. The percentage of recorveries of heart function at 30 minute after postischemic working heart perfusion were : heart rate $91.6{\pm}3.1$% (P<0.01)m oeaj airtuc oressyre $83{\pm}3$% (P<0.01), coronary flow $70{\pm}8$% (P<0.05) and aortic flow flow rate $39{\pm}9.3$% (P<0.05) in the Young & GIK group. This percentage of recoveries of the Young & GIK group was significantly greater than the control group. In the Bretschneider group, the percentage of recoveries were : heart rate $87.8{\pm}7.5$%(P<0.05), peak aortic pressure $71{\pm}2.3$% (P<0.05) and aortic flow rate $33.2{\pm}6.6$%(P<0.05). hte percentage of recoveries were significantly greater than in the control group. In the $K^{+}$ Albumin group, recoveries of heart function were poor. 3. Total CPK leakage was $131.2{\pm}12.75$IU/30 min/gm. dry weight in the control group, $50.65{\pm}12.75$IU in the Young & GIK gruop, $69.40{\pm}32.21$Iu in Bretschneider group, and $103.65{\pm}15.47$IU in the $K^{+}$ Albumin group during the 30 minute postischemic Langendorff reperfusion. Total CPK leakage was significantly less (P<0.001) in the Young & GIK group, than in the control group. 4. Direct correlatin between percentage recovery of aortic flow rate and total amount of CPK leakage from Myocardium was noticed.(Correlation Coefficient r = 0.76, P<0.001). 5. Mild perivascular edema was the only finding of light microscopic study of myocardium after 60 minute ischemic arrest with cold cardioplegic solutions and hypothermla.

• Journal of Chest Surgery
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• v.17 no.4
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• pp.574-586
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• 1984

Although corticosteroid have been shown to stabilize lysosomal membranes and prevent release of hydrolytic enzymes, the mechanism of membrane stabilization remains obscure. This study described functional assessment of efficiency of methylprednisolone in GIK solution by using a isolated Rat Heart Model. Isolated rat heart were subjected to a 2-minute period of coronary infusion with a cold GIK or methylprednisolone mixed cold GIK solution immediately before and also at the midpoint of a 60-minute period of hypothermic [$10{\pm}1^{\circ}C$] ischemic arrest. The result of this were as follow: 1.Spontaneous heart beat after ischemic arrest occurred 11 second later after Langendorffs reperfusion in the methylprednisolone mixed GIK group and 14 second later in the control group. 2.The percentage of recoveries of heart rate at 30 minute after postischemic working heart perfusion was 88.6\ulcorner.6% in the methylprednisolone mixed GIK group. This percentage of recovery was not significantly greater than the control group. 3.The percentage of heart function at 30 minute after postischemic working heart perfusion were; peak aortic pressure $90.8{\pm}4.5%$ coronary flow $87.5{\pm}1.45$ and aortic flow $74.9{\pm}11.8%$ in the methylprednisolone mixed GIK group. This percentage of recovery was significantly greater than the control group. [p<0.05]

• Journal of Biomedical Engineering Research
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• v.30 no.4
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• pp.294-305
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• 2009

The bio signals essentially have different characteristics in each person. And the main purpose of automatic diagnosis algorithm based on bio signals focuses on discriminating differences of abnormal state from personal differences. In this paper, we propose automatic ECG diagnosis algorithm which discriminates normal heart beats from premature ventricular contraction using optimization of wavelet parameterization to solve that problem. The proposed algorithm optimizes wavelet parameter to let energy of signal be concentrated on specific scale band. We can reduce the personal differences and consequently highlight the differences coming from arrhythmia via this process. The proposed algorithm using ELM as a classifier show high discrimination performance between normal beat and PVC. From the experimental results on MIT-BIH arrhythmia database the performances of the proposed algorithm are 98.1% in accuracy, 93.0% in sensitivity, 96.4% in positive predictivity, and 0.8% in false positive rate. This results are similar or higher then results of existing researches in spite of small human intervention.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.3
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• pp.198-205
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• 2005

In this paper, we proposed a new algorithm for the separation of fetal ECG from single channel abdominal ECG. The algorithm consists of a stage of demixing vector calculation for initial signal and a stage of fetal beat detection for the rest of signal. The demixing vector was obtained by applying independent component analysis technique to projected signals into time-frequency domain. For the test of this algorithm, simulation signals, De Lathauwer's data and some measured data, which was acquired from 8 healthy volunteers whose pregnant periods ranged from 22 weeks to 35 weeks and whose ages from 27 to 37, were used. For each data, the accuracy of fetal beat detection was $100\%$ and with the location of fetal beats, fetal heart rate variability and morphology could be offered. In conclusion, this proposed algorithm showed the possibility of fetal beat separation with a single channel abdominal ECG and it might be adopted to a fetal health monitoring system, by which a single channel abdominal ECG is acquired.

• Proceedings of the KIEE Conference
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• 1998.11b
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• pp.663-665
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• 1998

The purpose of this paper is development of portable cardiovascular signal processing device. Beat-to-beat fluctuation in heart rate, respiration, and blood pressure have been known to be meditated by autonomic nervous system activities convergent on various effector organs. This system consists of data acquisition module, main data processing module and graphic LCD module. The data acquisition module is developed for data aquisition, data multiplexing and interfacing with main data processing system. And, main data processing module is developed for data storing, data processing and interfacing with graphic LCD module. The main processing system is based on 32-bit microprocessor.

• Journal of Veterinary Clinics
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• v.16 no.2
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• pp.478-481
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• 1999

A 8 years old male Pomeranian weighing 4 kg was referred because of coughing of 4 months' duration. Heart sounds and cardiac apex beat were showed more intense on the right side. On radiographic views, loss of normal line of the diaphragm, gas-containing intestines and stomach in thoracic cavity, and right displacement of heart were observed. Ultrasonography revealed that liver located adjacent to the heart. Although the dog died due to severe respiratory disorder in surgical procedure, in thoracic and abdominal surgery, a large defect was found in the left and right ventral muscular portion and left central tendon of the diaphragm, extending from the esophageal hiatus to rib. Left and right cranial lobe of liver, small intestines, stomach and spleen were herniated in the thoracic cavity. Because of the size and chronicity of the defect in the diaphragm, closure was impossible with an abdominal muscle graft.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.168.3-168
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• 2001

The purpose of this paper is to find the relations between the virtual reality created by the ship´s bridge simulator (simulator) at Radar Navigation Experiment and Research Facility in Kobe University of Mercantile Marine (KUMM) and the observer´s response to it. In short, we analyze the observer´s heart rate variability (R-R interval) in navigational condition seasick impression by simulator occurred, and present the R-R Interval and the stress of observer with SNS and PNS calculated by STFT. In this experiment, rolling of the ship was simulated and presented to the observer. Rolling was simulated only visually not physically or mechanically while the balancing movement and heart beat of the observer were measured and processed to produce the measures for body response to the artificially created visual environment. The results show that even a ...

• Journal of the Korea Society of Computer and Information
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• v.22 no.5
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• pp.65-72
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• 2017

Premature Ventricular Contraction(PVC) arrhythmia is most common abnormal-heart rhythm that may increase mortal risk of a cardiac patient. Thus, it is very important issue to identify the specular portraits of PVC pattern especially from the patient. In this paper, we propose a new method to extract the characteristics of PVC pattern by applying K-means machine learning algorithm on Heart Rate Variability depicted in Poinecare plot. For the quantitative analysis to distinguish the trend of cluster patterns between normal sinus rhythm and PVC beat, the Euclidean distance measure was sought between the clusters. Experimental simulations on MIT-BIH arrhythmia database draw the fact that the distance measure on the cluster is valid for differentiating the pattern-traits of PVC beats. Therefore, we proposed a method that can offer the simple remedy to identify the attributes of PVC beats in terms of K-means clusters especially in the long-period Electrocardiogram(ECG).

• Journal of Chest Surgery
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• v.24 no.11
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• pp.1081-1089
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• 1991

Atrial fibrillation is characterized by beat to beat irregularity of shape, size, conduction time and polarity. The mechanism of atrial fibrillation can be explained by so called "Multiple wavelet theory". The adverse effect of atrial fibrillation is the decrease of cardiac output by absence of atrial kick[10 ~ 15%] and the possibility of thrombosis in the left atrium which is dangerous to develop the thromboembolism is increased. The present study was designed to assess the effect of overdrive pacing on the suppression of recurring of atrial fibrillation after open heart surgery and the results were summarized as follows: 1. There were no significant differences of factors between converting patients and non-converting patients to normal sinus rhythm by electric cardioversion after open heart surgery. 2. Among converting patients to normal sinus rhythm, there were no significant differences of factors between study group and control group. 3. Cardiothoracic Ratio on the preoperative chest film was significantly larger in the patients of recurring atrial fibrillation within 72hrs than in the patients of maintaining normal sinus rhythm. [61.7$\pm$ 1.4% vs 67.7$\pm$2.4%, p=0.03] 4. There was a significant difference of suppressive effects between overdrive pacing group and control group among recurred cases until 24, 48, and 72hours [Fisher`s exact test ; p=0.037, p=0.076, p=0.53, respectively] 5. There was a difference of the delay of recurring of atrial fibrillation between study group and control group among recurred cases within 72 hours.[53.4$\pm$6.9hr vs. 19.3$\pm$3.8 hr, p<0.01] We think that the overdrive pacing may suppress the natural pacemaker and the converted normal sinus rhythm is maintained longer than control group during critical immediate postoperative period.ve period.