• Proceedings of the KOSOMBE Conference
• /
• v.1992 no.11
• /
• pp.146-149
• /
• 1992

The cardiac depolarization model using three dimensional ventricular model is simulated. To study this theme, we constructed a cardiac ventricular model and simulated the cardiac activation process using the action potential duration and the activation time. The cardiac potential model is generated by the logical combination of the elliptic equations. The action potential duration could be obtained from the fact that it is linearly distributed between model cells. The cardiac activation process was simulated by the law of "all-or-none". Based on the activation time and the action potential duration the cardiac potential at the arbitrary time after the activation of the model cell was computed. To test the validity of model, the comparison the results of model simulation with the physiological data was performed.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1996.11a
• /
• pp.260-266
• /
• 1996

In this paper, we presents neural network identification and control of highly complicated nonlinear Left Ventricular Assist Device(LVAD) system with a pneumatically driven mock circulation system. Generally the LVAD system need to compensate nonlinearities. Hence, it is necessary to apply high performance control techniques. Fortunately, the neural network can be applied to control of a nonlinear dynamic system by learning capability. In this study, we identify the LVAD system with Neural Network Identification. Once the NNI has learned the dynamic model of LVAD system, the other network, called Neural Network Controller(NNC), is designed for control of a LVAD system. The ability and effectiveness of identifying and controlling a LVAD system using the proposed algorithm will be demonstrated by computer simulation.

• Journal of Chest Surgery
• /
• v.12 no.3
• /
• pp.274-280
• /
• 1979

A case of successful surgical correction of double-outlet right ventricle with situs inversus, dextrocardia, subaortic ventricular septal defect, and pulmonic stenosis is described. The great vessels were normally related but in mirror-image arrangement. Another coronary artery anomaly, single origin of coronary artery and a large anomalous coronary artery coursed across the right ventricular outflow tract, was accompanied. Intracardiac repair with a Dacron tunnel conduit and extracardiac jumping graft with a valved conduit gave an excellent result.

• Journal of Chest Surgery
• /
• v.30 no.4
• /
• pp.419-422
• /
• 1997

In small children with left ventricular outflow tract obstruction, a few methods of surgical treatment could be considrred. The pulmonary autogrart provides a promising options for aortic valve replacement as part of the aortoventriculoplasty procedure in children. We report a successfully treated congenital aortic stcnoinsufricicncy with severe left ventricular dysfunction in an early infant with the aortoventriculoplasty using thc pulmonary autograft (the Ross-Konno procedure).

• The Korean Journal of Nuclear Medicine
• /
• v.39 no.2
• /
• pp.133-140
• /
• 2005

The potential for recovery of left ventricular dysfunction after myocardial revascularization represents a practical clinical definition for myocardial viability. The evaluation of viable myocardium in patients with severe global left ventricular dysfunction due to coronary artery disease and with regional dysfunction after acute myocardial infarction is an important issue whether left ventricular dysfunction may be reversible or irreversible after therapy. If the dysfunction is due to stunning or hibernation, functional improvement is observed. but stunned myocardium may recover of dysfunction with no revascularization. Hibernation is chronic process due to chronic reduction in the resting myocardial blood flow. There are two types of myocardial hibernation: "functional hibernation" with preserved contractile reserve and "structural hibernation" without contractile reserve in segments with preserved glucose metabolism. This review focus on the application of F-18 FDG and other radionuclides to evaluate myocardial viability. In addition the factors influencing predictive value of FDG imaging for evaluating viability and the different criteria for viability are also reviewed.

• Journal of Chest Surgery
• /
• v.19 no.3
• /
• pp.457-463
• /
• 1986

Truncus Arteriosus is uncommon, accounting for 0.4%-2.8% of all congenital cardiac malformations. Truncus arteriosus has a poor prognosis in early infancy and defined as "a single arterial trunk that leaves the heart by way of a single arterial valve and that gives rise to the coronary, systemic and one or both pulmonary arteries directly." Through antemortem study of patients with truncus arteriosus the development of surgical techniques for palliation and correction was established. Recently we had surgical experience of truncus arteriosus - Collett '||'&'||' Edwards type 2. The main pulmonary artery was originated from truncus at right posterolateral aspect. Truncal valve was tricuspid with good coaptation. Ventricular septal defect was subarterial type of 2.0 cm in diameter. After detachment of the main pulmonary artery from truncus, truncus was repaired directly. Ventricular septal defect was closed with Dacron patch. Extracardiac valved conduit [Carpentier-Edwards: 16mm] was employed for making continuity between right ventricular outflow tract and pulmonary artery. Postoperatively, incomplete right bundle branch block on electrocardiogram was continued. Patient was died due to respiratory failure in postoperative 40 days.s.

• Journal of Biomedical Engineering Research
• /
• v.6 no.1
• /
• pp.55-64
• /
• 1985

The cardiac activation process using three dimensional ventricular model is simulated.To study this theme, we constructed a cardiac ventricular model and simulated the cardiac activation process using the action potential duration and the activation time. The cardiac ventricular model is generated by the logical combination of the elliptic equations. The action potential duration could be obtained from the fact that it is linearly distributed between model cells. The cardiac activation process was simulated by the law of "all-or-none" Based on the activation time and the action potential do-ration the cardiac potential at the arbitrary time after the activation of the model cell was computed. To test the validity of model, the comparison of the results of model simulation with the physiological data was performed. In conclusion, this model shows the simular results which is comparable to the real conduction of the cardiac excitation.xcitation.

• Journal of the Korea Society of Computer and Information
• /
• v.22 no.5
• /
• pp.65-72
• /
• 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 Institute of Control, Robotics and Systems
• /
• v.4 no.3
• /
• pp.315-320
• /
• 1998

In this paper, we present the PID control method for the controlling flow rate of highly complicated nonlinear Left Ventricular Assist Device(LVAD) with pneumatically driven mock circulatory system. Beat Rate (BR), Systole-Diastole Rate (SDR) and flow rate are used as the main variables of the LVAD system. System modeling is completed using the neural network with input variables (BR, SDR, their derivatives, actual flow) and an output valiable(actual flow). Then, as the basis of this model, we perform the simulation of PID control to predict the performance and tendency of the system and control the flow rate of LVAD system using the PID controller. The ability and effectiveness of identifying and controlling a LVAD system using the proposed algorithm will be demonstrated through computer simulation and experiments.

• Annals of Clinical Neurophysiology
• /
• v.17 no.2
• /
• pp.80-81
• /
• 2015

Syncopes are the most common non-epileptic attacks mimicking epileptic seizures. Among them, cardiogenic syncope is potentially life threatening. A 49 year old man was refered for the recurrent episodes of loss of consciousness with tonic posture and upward eyes deviation. The electrocardiogram showed polymorphologic ventricular tachycardia during attacks, which normalized after that. He was treated with isoproterenol and symptoms subsided. Here, we report a case of ventricular tachycardia manifested as epileptic seizures.