• Investigative Magnetic Resonance Imaging
• /
• v.18 no.3
• /
• pp.244-252
• /
• 2014

Purpose : We proposed a multi-physiological signals based real-time intelligent triggering system(MITS) for Cardiac MRI. Induced noise of the system was analyzed. Materials and Methods: MITS makes cardiac MR imaging sequence synchronize to the cardiac motion using ECG, respiratory signal and second order derivative of $SPO_2$signal. Abnormal peaks due to arrhythmia or subject's motion are rejected using the average R-R intervals and R-peak values. Induced eddy currents by gradients switching in cardiac MR imaging are analyzed. The induced eddy currents were removed by hardware and software filters. Results: Cardiac MR images that synchronized to the cardiac and respiratory motion are acquired using MITS successfully without artifacts caused by induced eddy currents of gradient switching or subject's motion or arrhythmia. We showed that the second order derivative of the $SPO_2$ signal can be used as a complement to the ECG signals. Conclusion: The proposed system performs cardiac and respiratory gating with multi-physiological signals in real time. During the cardiac gating, induced noise caused by eddy currents is removed. False triggers due to subject's motion or arrhythmia are rejected. The cardiac MR imaging with free breathing is obtained using MITS.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
• /
• 2000.11a
• /
• pp.81-87
• /
• 2000

Beat-to-beat changes in heart period (heart period variability, HPV) are mediated by fluctuations in autonomic activity. Spectral analysis is used to quantify such fluctuations in the range of 0.15-0.40 Hz (high frequency, HF), which are influenced primarily by parasympathetic factors. These fluctuations are often referred to as RSA (respiratory sinus arrhythmia), the physiological phenomenon extracted by spectral analysis and other methods including histograms of heart rate ( HR), deviations of HR etc. Respiratory sinus arrhythmia indexing with peak-to-valley method suggested by Grossman et at., (1981) yields a simple range statistic and is quantified on breath-by-breath basis, thus being quite sensitive and less dependent on recording time as compared to spectral analysis. It is strongly recommended to use at least 1 min epoch to asses HF component of HPV and at least 2 min fer low frequency (LF) of HPV and even 5 min far valid clinical assessment. Peak-to-valley statistic is limited to RSA index only, but has its pragmatic advantages. Most important is possibility of its application far relatively small epoch analysis. We used short periods (20,30, 40 sec only) and off-line analysis of RSA using ECG and respiration curve this method of assessment and proved that this method is more practically effective. The RSA index was not so far dependent on respiration pattern differences and reflected actual vagal control of HR and were accompanied by low HR under some high stress conditions and in an aversive affective visual stimulation experiments. Another factor that might modulate cardiac chronotropic response is the interaction of sympathetic and parasympathetic inputs on sino-atrial (SA) node level, because responses to vagal influences are known to be proportional to ongoing sympathetic activity, that is so called accentuated antagonism. Since sympathetic outflow (increment of influences on SA) under negative emotions or stress was high in almost all physiological responses, vagal effects on HR could be therefore potentiated, leading to masking of output cardiac response seen in HPV, In the case of moderate sympathetic activation, on the other hand, autonomic interactions in cardiac control appear to be minimal. Thus RSA index appears to be an effective alternative method to assess and measure spectral HPV.

• The Journal of Internal Korean Medicine
• /
• v.25 no.4
• /
• pp.346-355
• /
• 2004

Background & Object : The aim of this study was to investigate the usefulness of electrogastrography on differential diagnosis of deficiency or excess Condition in patients with functional dyspepsia Methods : Selected symptoms for diagnosis of deficiency and excess in functional dyspepsia have been reviewed in some literatures, notably within Oriental medicine, Donguibogam and Gogeumdoseojipseong-uibujeolrok. This is what was investigated in this study. 93 patients (male 32, female 61) were divided into three groups; Non-pain group, Pre-treatment pain group (chief complain was abdominal pain at the first medical examination), and Mid-treatment pain group(they had no pain at the time of first medical examination, but showed abdominal pain within two weeks). 10 healthy people participated as normal controls. Gastric motility were recorded and analyzed using electrogastrography during fasting and postprandial period. In assessment, effectiveness was divided into validity, sensitivity and specificity. Results : Epigastric pain reflected the tendency for excess condition in comprehensive diagnosis, which was linked with postprandial arrhythmia in electrogastrography(p=0.001). Postprandial arrhythmia detected abdominal pain with a validity of 78.6%, a sensitivity of 79.2%, and a specificity of 78%(p<0.001). Conclusions : Results 1Tom Postprandial arrhythmia in electrogastrography support that the index of excess condition in the comprehensive diagnosis of symptoms is useful for patients with functional dyspepsia.

• Journal of Chest Surgery
• /
• v.33 no.4
• /
• pp.310-315
• /
• 2000

Background: A retrospectiye study was done for understanding morbidity and mortality after major lung resection. Material and Method: From June 1994 to August 1998, 203 patients received major lung resections for various causes. There were 142 males and 62 females with a mean age of 47.5 years. Initial complains were cough in 47.8%, sputum in 33.0%, hemoptysis or blood-tinged sputum in 23.2%, dyspnea in 18.2%, chest pain in 15.3%, weight loss in 10.8%, fever and chill in 4.9%. There were no complaints in 5.9% of the total patients. The underlying diseases were lung tumor(102 cases/50.2%), bronchectasis(28 cases/13.8%), aspergillosis(24 cases/1.8%), tuberculosis(20 cases/9.9%) and others (29 cases/66.5%) and pneumonectomy(68 cases/33.5%). The postoperative complications were classified as : empyema, BPF, respiratory problem, persistent air leakage over 7 days, arrhythmia, ventilator applied over 24 hours, bleeding, wound infection and chylothorax. The postlobectomy complications were revealed as follow: empyema(3.7%), BPF(2.2%), respiratory problem(5.2%), persistent air leakage over 7days(8.9%), arrhythmia(2.2%), ventilator applied over 24 hours(2.2%), bleeding(1.5%), wound infection(2.9%), chylothorax(0.7%). The postpneumonectomy complications were revealed as follow : empyema(5.9%), BPF (5.9%), respiratory problem(17.6%), persistent air leakage over 7days(0%), arrhythmia(5.4%), ventialtor apply over 24 hours(7.4%), bleeding (7.4%), wound infection(2.9%) and chylothorax(1.5%). Reoperation was done in 8 cases (4.0%). There were 5.8% operative mortalities in pneumonectomy and 0.7% in lobectomy.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.20 no.2
• /
• pp.427-436
• /
• 2016

In general, QRS duration represent a distance of Q start and S end point. However, since criteria of QRS duration are vague and Q, S point is not detected accurately, arrhythmia classification performance can be reduced. In this paper, we propose extraction of Q, S start and end point RS feature based on phase transition tracking method after we detected R wave that is large peak of electrocardiogram(ECG) signal. For this purpose, we detected R wave, from noise-free ECG signal through the preprocessing method. Also, we classified QRS pattern through differentiation value of ECG signal and extracted Q, S start and end point by tracking direction and count of phase based on R wave. The performance of R wave detection is evaluated by using 48 record of MIT-BIH arrhythmia database. The achieved scores indicate the average detection rate of 99.60%. PVC classification is evaluated by using 9 record of MIT-BIH arrhythmia database that included over 30 premature ventricular contraction(PVC). The achieved scores indicate the average detection rate of 94.12% in PVC.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.19 no.1
• /
• pp.192-200
• /
• 2015

Several algorithms have been developed to classify arrhythmia which rely on specific ECG(Electrocardiogram) database. Nevertheless personalized difference of ECG signal exist, performance degradation occurs because of carrying out diagnosis by general classification rule. Most methods require accurate detection of P-QRS-T point, higher computational cost and larger processing time. But it is difficult to detect the P and T wave signal because of person's individual difference. Therefore it is necessary to classify the pattern by analyzing personalized ECG signal and extracting minimal feature. Thus, QRS pattern Analysis of personalized ECG Signal by Q, R, S peak variability is presented in this paper. For this purpose, we detected R wave through the preprocessing method and extract eight feature by amplitude and phase variability. Also, we classified nine pattern in realtime through peak and morphology variability. PVC, PAC, Normal, LBBB, RBBB, Paced beat arrhythmia is evaluated by using 43 record of MIT-BIH arrhythmia database. The achieved scores indicate the average of 93.72% in QRS pattern detection classification.

• The Korean Journal of Physiology and Pharmacology
• /
• v.28 no.4
• /
• pp.313-322
• /
• 2024

Mutations within the SCN5A gene, which encodes the α-subunit 5 (Na_V1.5) of the voltage-gated Na⁺ channel, have been linked to three distinct cardiac arrhythmia disorders: long QT syndrome type 3, Brugada syndrome (BrS), and cardiac conduction disorder. In this study, we have identified novel missense mutations (p.A385T/R504T) within SCN5A in a patient exhibiting overlap arrhythmia phenotypes. This study aims to elucidate the functional consequences of SCN5A mutants (p.A385T/R504T) to understand the clinical phenotypes. Whole-cell patch-clamp technique was used to analyze the Na_V1.5 current (I_Na) in HEK293 cells transfected with the wild-type and mutant SCN5A with or without SCN1B co-expression. The amplitude of I_Na was not altered in mutant SCN5A (p.A385T/R504T) alone. Furthermore, a rightward shift of the voltage-dependent inactivation and faster recovery from inactivation was observed, suggesting a gain-of-function state. Intriguingly, the co-expression of SCN1B with p.A385T/R504T revealed significant reduction of I_Na and slower recovery from inactivation, consistent with the loss-of-function in Na⁺ channels. The SCN1B dependent reduction of I_Na was also observed in a single mutation p.R504T, but p.A385T co-expressed with SCN1B showed no reduction. In contrast, the slower recovery from inactivation with SCN1B was observed in A385T while not in R504T. The expression of SCN1B is indispensable for the electrophysiological phenotype of BrS with the novel double mutations; p.A385T and p.R504T contributed to the slower recovery from inactivation and reduced current density of Na_V1.5, respectively.

• Journal of Chest Surgery
• /
• v.26 no.5
• /
• pp.403-408
• /
• 1993

The atrioventricular node reentrant tachycardia[AVNRT] is a common type of supraventricular tachycardias. Recently we experienced two cases of AVNRT. One is AVNRT with severe aortic regurgitation[grade IV] and the other is AVNRT with patent ductus arteriosus. Dissection of perinodal tissue has been successfully carried out in the beating heart under the normothermic cardiopulmonary bypass, and aortic valve replacement and ligation of patent ductus arteriosus were also performed, respectively. Postoperatively, permanent atrioventricular block was not occured and AVNRT was not developed during the follow up. We propose that the surgical dissection of perinodal tissue is a simple and effective treatment for the patient with refractory AVNRT.

• Journal of Chest Surgery
• /
• v.11 no.2
• /
• pp.123-128
• /
• 1978

This 18 year old girl with total anomalous venous connection, which was corrected surgically for the first time in Korea, is presented here. This patient has mild cyanosis, ejection systolic murmur with splitting of $S_2$ ,identical $O_2$ saturation of bleed samples from right and left chambers of the heart. The type was supracardiac TAPVC. On conventional cardiopulmonary by pass was used, and an right sided approach was employed. Post-op. course was smooth except for transient arrhythmia, low blood pressure and jaundice. She left hospital in a good general conditions.

• Journal of Biomedical Engineering Research
• /
• v.12 no.2
• /
• pp.121-130
• /
• 1991

This paper presents a QRS recognition algorithm using attribute grammar and its interpreter. This system extracts primitive and their attributes by linear approximation technique and then represented linguistic formation using attribute grammar. These nonterminals and their attributes are evaluated by attribute grammar interpreter. The performance of the QRS recognition algorithm has been evaluated using arrhythmia simulator and CSE ECG library.