• Journal of the Korean Society for Precision Engineering
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• v.21 no.4
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• pp.19-23
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• 2004

생체에서 발생되는 생체신호는 신호의 발생원에 따라서, 신호의 물리적 특성에 따라서, 또는 이를 측정하는 센서의 특성에 따라서 분류할 수 있으며, 그 중에서도 임상적 진료를 위한 의료의 범위를 포함하여 다른 분야에도 광범위하게 활용될 수 있는 생체 신호는 전기적인 형태로 측정되는 생체 전기 신호라고 할 수 있다. 여기에서는 생체에서 측정되는 전기적인 신호가 어떻게 활용되고 또 활용될 수 있는지 그 응용 범위에 대하여 살펴보고자 한다.(중략)

• Journal of Chest Surgery
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• v.12 no.4
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• pp.336-338
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• 1979

The electrocardiographic changes produced at surgery in all patients undergoing total correction of tetralogy of Fallot at the Seoul National University Hospital from 1961 through August 1979, were reviewed. Particular attention was directed to the presence of postoperative right bundle branch block combined with left anterior hemiblock and its prognosis. 14 patients [9.4%] out of 149 who were survived for 30 days postoperatively, showed right bundle branch block with left anterior hemiblock pattern in electrocardiography. But no complete heart block was occurred in these l 4 patients during the follow up periods of 2-56 months.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.6
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• pp.1257-1264
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• 2019

The traditional cuff-based method for BP(Blood Pressure) measurement is not suitable for continuous real-time BP measurement techniques. For this reason, the previous studies estimated various blood pressures by fusion with the electrocardiography (ECG) and photoplethysmogram (PPG) sensor signals. However, conventional techniques based on PPG bio-sensing measurement face many challenging issues such as noisy supply fluctuation, small pulsation, and drifting non-pulsatile. This paper proposed a novel BP estimation methods using PPG and ECG sensors, which can be derived from the relationship between PPG and ECG using PTT(Pulse Transit Time) and PWV(Pulse Wave Velocity). Unlike conventional height ratio features, which are extracted on the basis of the peaks in the PPG and ECG waveform. The proposed method can be reliably obtained even if there are missing peaks among the sensed PPG signal. The increased reliability comes from periodical estimation of the peak-to-peak interval time using ECG and PPG. After 250,000 times trials of the blood pressure measurement, the proposed estimation technique was verified with the accuracy of ±28.5% error, compared to a commercialized BP device.

• Journal of Pharmacopuncture
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• v.13 no.3
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• pp.15-46
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• 2010

Objectives: This study was performed to analyse the effects of Sweet Bee Venom(Sweet BV) on cardiovascular system in the conscious telemetered Beagle Dogs. Methods: All experiments were conducted at Biotoxtech Company, a non-clinical studies authorized institution, under the regulations of Good Laboratory Practice (GLP). Male Beagle dogs of 13-19 months old were chosen for the pilot study and surgical implantation was performed for conscious telemetered Beagle dogs. And after confirming condition of Beagle dogs was stable, Sweet BV was administered 4 times(first: 0.0 mg/kg, 2nd: 0.01 mg/kg, 3rd: 0.1 mg/kg, and forth: 0.5 mg/kg, one time/week) in thigh muscle of Beagle dogs. And blood pressure, heart rate, electrocardiography and clinical responses were measured. Equal amount of normal saline to the Sweet BV experiment groups was administered to the control group. Results: 1. In the analysis of body weight and taking amount, Beagle dogs did not show significant changes. 2. In the clinical observation, responses of pain and edema were showed depend on dosage of Sweet BV. 3. In the analysis of blood pressure, treatment with Sweet BV did not show significant changes in the dosage of 0.01 mg/kg, but in the dosage of 0.1 mg/kg and 0.5 mg/kg, treatment with Sweet BV increased blood pressure significantly. 4. In the analysis of heart rate, treatment of Sweet BV did not show significant changes in all dosage and period. 5. In the analysis of electrocardiography, treatment of Sweet BV was not showed significant changes in all dosage and period. Conclusion: Above findings suggest that Sweet BV is relatively safe treatment in the cardiovascular system. But in the using of over dosage, Sweet BV may the cause of increasing blood pressure. Further studies on the subject should be conducted to yield more concrete evidences.

• Clinical and Experimental Pediatrics
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• v.59 no.11
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• pp.451-455
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• 2016

Purpose: Neurocardiogenic syncope (NCS) is the most frequent cause of fainting during adolescence. Inappropriate cardiovascular autonomic control may be responsible for this clinical event. The head-up tilt test has been considered a diagnostic standard, but it is cumbersome and has a high false-positive rate. We performed a study to evaluate whether P-wave dispersion (PWD) could be a useful electrocardiographic parameter of cardiac autonomic dysfunction in children with NCS. Methods: Fifty-four patients with NCS (28 boys and 26 girls; mean age, $12.3{\pm}1.4$ years) and 55 age- and sex-matched healthy controls were enrolled. PWD was obtained as the difference between maximum and minimum durations of the P wave on standard 12-lead electrocardiography in all patients and controls Results: The value of PWD was significantly higher in the syncope group than in the control group ($69.7{\pm}19.6$ msec vs. $45.5{\pm}17.1$ msec, respectively; P<0.001). The minimum duration of P wave was shorter in the syncope group than in the control group ($43.8{\pm}16.8$ msec vs. $53.5{\pm}10.7$ msec, respectively; P<0.001). Left atrial volume was not different between the groups on transthoracic echocardiography. Conclusion: PWD on echocardiography could be used as a clinical parameter in patients with NCS.

• Journal of Broadcast Engineering
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• v.18 no.4
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• pp.543-549
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• 2013

Motion artifacts of central and autonomic nervous system signals degrades the performance of the bio-signal based human factor analysis. Firstly, we propose a defining method of motion artifact section by analyzing successive image frames. Motion artifact section is defined when the amount of motion is greater than the pre-defined threshold. In here, the amount of motion is estimated by first derivation of image frames at temporal domain. Secondly, we propose another defining method of motion artifact section through designing 2D Gaussian probability density function model by analyzing feature vectors of one cycle of signal such as length and amplitude. The defined motion artifact sections are interpolated on the basis of 1D Gaussian function. At result of applying the method into photoplethysmography signal, we confirmed that the calculated heartbeat rate from the restored photoplethysmography came up to the one from electrocardiography. Also, we found that the video based method generated relatively more false acceptance of motion artifact section and the probability density function based method generated relatively more false rejection of motion artifact section.

• Journal of Biomedical Engineering Research
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• v.17 no.4
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• pp.449-458
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• 1996

Most of the conventional electrocardiowaphs foil to detect signals other than P-QRS-T due to the limited SNR and bandwidth. High-resolution electrocardiography(HRECG) provides better SNR and wider bandwidth for the detection of micro-potentials with higher frequency components such as vontricular late potentials(LP). We have developed a HRECG using uncorrected XYZ lead for the detection of LPs. The overall gain of the amplifier is 4000 and the bandwidth is 0.5-300Hz without using 60Hz notch filter. Three 16-bit A/D converters sample X, Y, and Z signals simultaneously with a sampling frequency of 2000Hz. Sampled data are transmitted to a PC via a DMA-controlled, optically-coupled serial communication channel. In order to further reduce the noise, we implemented a signal averaging algorithm that averaged many instances of aligned beats. The beat alignment was carried out through the use of a template matching technique that finds a location maximizing cross-correlation with a given beat tem- plate. Beat alignment error was reduced to $\pm$0.25ms. FIR high-pass filter with cut-off frequency of 40Hz was applied to remove the low frequency components of the averaged X, Y, and Z signals. QRS onset and end point were determined from the vector magnitude of the sigrlaIL and some parameters needed to detect the existence of LP were estimated. The entire system was designed for the easy application of the future research topics including the optimal lead system, filter design, new parameter extraction, etc. In the developed HRECG, without signal averaging, the noise level was less than 5$\mu$V$_rms RTI$. With signal averaging of at least 100 beats, the noise level was reduced to 0.5$\mu$V$_rms RTI$, which is low enough to detect LPs. The developed HRECG will provide a new advanced functionality to interpretive ECG analyzers.

• Pediatric Infection and Vaccine
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• v.27 no.3
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• pp.184-189
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• 2020

Lyme disease is a common vector-borne disease caused by Borrelia burgdorferi. Erythema migrans represents the most common manifestation during the early phase of this disease; however, systemic manifestations involving the nervous system, joints, or heart are known to occur. We report a case of Lyme disease accompanied by cardiac complications in a 13-year-old Korean male adolescent. The patient developed annular erythematous lesions on his lower extremities after a field trip during his visit to Connecticut, USA, for a boarding school camp, and his skin lesions were consistent with erythema migrans. Indirect immunofluorescence assay and Western blot analysis for Lyme immunoglobulin M showed positive results. Electrocardiography revealed a first-degree atrioventricular block, and he was diagnosed with Lyme carditis and received a 4-week course of oral doxycycline. Follow-up electrocardiography performed a week later revealed normal findings, and the patient showed an uneventful recovery. Lyme carditis often presents as an asymptomatic heart block that can progress to an advanced heart block; however, this condition is reversible with appropriate antibiotic treatment.

• Childhood Kidney Diseases
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• v.27 no.2
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• pp.105-110
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• 2023

Purpose: To analyze electrocardiograms (ECGs) of patients with a salt-losing tubulopathy (SLT) and to determine the frequency and risk factors for long QT and arrhythmia. Methods: A total of 203 patients aged <19 years with SLT, specifically Bartter syndrome and Gitelman syndrome, who had a 12-lead ECG were included in this retrospective study. We analyzed the presence of an arrhythmia or prolonged corrected QT (QTc) on ECGs obtained for these patients. Demographic and laboratory data were compared between patients with abnormal and normal ECG findings. Results: Out of the 203 SLT patients, 38 (18.7%) underwent electrocardiography and 10 (40.0%) of 25 patients with inherited SLT had abnormal ECG findings, including prolonged QTc and arrhythmias. The abnormal ECG group had significantly lower serum potassium levels than the normal group (median [interquartile range]: 2.50 mmol/L [2.20-2.83] vs. 2.90 mmol/L [2.70-3.30], P=0.036), whereas other serum chemistry values did not show significant differences. The cutoff level for a significant difference in QTc interval was serum potassium level <2.50 mmol/L. One cardiac event occurred in a 13-year-old boy, who developed paroxysmal supraventricular tachycardia and underwent cardiac ablation. No sudden cardiac deaths occurred in this cohort. Conclusions: The incidence of ECG abnormalities in patients with inherited SLT was 40.0%, whereas the ECG screening rate was relatively low (18.7%). Therefore, we recommend ECG screening in patients with inherited SLT, especially in those with serum potassium level <2.50 mmol/L.

• Journal of Chest Surgery
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• v.57 no.2
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• pp.205-212
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• 2024

Background: Postoperative atrial fibrillation (A-fib) is a serious complication of cardiac surgery that is associated with increased mortality and morbidity. Traditional 24-hour Holter monitors have limitations, which have prompted the development of innovative wearable electrocardiogram (ECG) monitoring devices. This study assessed a patch-type wearable ECG device (MobiCARE-MC100) for monitoring A-fib in patients undergoing cardiac surgery and compared it with 24-hour Holter ECG monitoring. Methods: This was a single-center, prospective, investigator-initiated cohort study that included 39 patients who underwent cardiac surgery between July 2021 and June 2022. Patients underwent simultaneous monitoring with both conventional Holter and patchtype ECG devices for 24 hours. The Holter device was then removed, and patch-type monitoring continued for an additional 48 hours, to determine whether extended monitoring provided benefits in the detection of A-fib. Results: This 72-hour ECG monitoring study included 39 patients, with an average age of 62.2 years, comprising 29 men (74.4%) and 10 women (25.6%). In the initial 24 hours, both monitoring techniques identified the same number of paroxysmal A-fib in 7 out of 39 patients. After 24 hours of monitoring, during the additional 48-hour assessment using the patch-type ECG device, an increase in A-fib burden (9%→38%) was observed in 1 patient. Most patients reported no significant discomfort while using the MobiCARE device. Conclusion: In patients who underwent cardiac surgery, the mobiCARE device demonstrated diagnostic accuracy comparable to that of the conventional Holter monitoring system.