• Journal of information and communication convergence engineering
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• 제19권2호
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• pp.93-101
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• 2021

Cardiac arrhythmias are common heart diseases and generally cause sudden cardiac death. Electrocardiogram (ECG) is an effective tool that can reveal the electrical activity of the heart and diagnose cardiac arrhythmias. We propose detection of P waves based on QRST cancellation zero-one substitution. After preprocessing, the QRST segment is determined by detecting the Q wave start point and T wave end point separately. The Q wave start point is detected by digital analyses of the QRS complex width, and the T wave end point is detected by computation of an indicator related to the area covered by the T wave curve. Then, we determine whether the sampled value of the signal is in the interval of the QRST segment and substitute zero or one for the value to cancel the QRST segment. Finally, the maximum amplitude is selected as the peak of the P wave in each RR interval of the residual signal. The average detection rate for the QT database was 97.67%.

• Clinical and Experimental Pediatrics
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• 제51권7호
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• pp.766-770
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• 2008

심장의 원발성 종양은 소아에서는 매우 드문 질환이다. 횡문근종은 태아, 영아 및 소아 연령에서 가장 흔한 원발성 심장 종양으로 결절성 경화증이 동반되는 것으로 보고되고 있다. 결절성 경화증은 뇌, 심장, 피부 및 기타 장기들을 침범하는 신경피부 증후군으로, 결절성 경화증을 가진 영아의 50-64%에서 동반된다. 심장 횡문근종은 종괴는 심방을 비롯하여 심실 중격과 심실벽에 다발성으로 존재하며 종양의 위치와 크기, 침범 정도에 따라 심장 유출로 협착 및 심부전과 같은 여러 가지 임상 양상을 보일 수 있다. 드물지만 부정맥을 주증상으로 발현하는 경우도 보고되고 있다. 하지만 대부분 심장의 횡문근종이 특별한 문제를 일으키지 않고 성장과 함께 쇠퇴되는 경향을 보이므로 극히 일부분에서만 장기적인 항부정맥제 사용이 요구된다. 환자의 최종적인 예후는 동반되는 뇌병변에 의해 결정되는 경향이 있다. 저자들은 상심실성 빈맥으로 입원치료 중 진단된 심장 횡문근종을 가진 결절성 경화증 1예를 경험하였기에 보고하는 바이다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1994년도 추계학술대회
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• pp.88-91
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• 1994

It is well known that multipoint and computerized intraoperative mapping systems improve the results of surgery for Wolff-Parkinson-White syndrome and show tremendous potential for opening an entirely new era of surgical intervention for the more common and lethal types of supraventricular tachyarrhythmias such as atrial flutter and atrial fibrillation. In addition, the ability to map and ablate the sometimes fleeting automatic atrial tachycardia is greatly enhanced by computerized mapping systems. In this study, we have developed 64 channel computerized data analysis system using microcomputer (Macintosh IIx) for basic research of electrophysiology and electrical propagation. The bipolar electrogram information is acquired from 64 cardiac sites simultaneously at a sampling rate of 1ksamples/sec with continuous and total data storage of up to 30 seconds. When the reference electrogram is selected and reference point is picked up, delay time from the reference point in displayed on two dimensional diagram of the heart. System design permits easy expansion to almost 256 simultaneous sites, This system is expected to enable us to study pathophysiology of cardiac arrhythmia and to improve the results of diagnosis and surgical treatment for cardiac arrhythmia.

• 대한수의사회지
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• 제40권2호
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• pp.145-156
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• 2004

심부정맥(Cardiac arrhythmia)이란 심장내 박동, 율동, 충동 발생 및 전도장애를 유도하는 질환을 말하며, 주로 심근경색이나 심장비대증 같은 심장의 해부학적 질환과 약물중독 및 전해질 불균형에 의해 발생한다. 부정맥은 정상적인 심근 활성을 차단하여 심장박출을 감소시키므로 때로 생명을 위협하기도 한다. 본 종설에서는 심장의 전도계에 관련된 정상생리와 부정맥의 병리적 발생기전 및 부정맥 치료제에 대한 분류 및 약리기전에 대해 기술하고자 한다.

• 한국정보통신학회논문지
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• 제26권1호
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• pp.76-84
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• 2022

부정맥은 심장 박동이 비정상 혹은 불규칙하게 뛰고 있는 상태를 말하며, 실신이나 심장돌연사 등과 같은 위험한 상황을 유발할 수 있기 때문에 이의 조기 검출은 매우 중요하다. 하지만 심전도 신호의 개인차로 인해 분류 시 성능하락이 나타날 수밖에 없다. 본 연구에서는 CNN-LSTM 하이브리드 결합 모델을 이용한 부정맥 분류 방법을 제안한다. 이를 위해 먼저 잡음을 제거한 ECG 신호에서 R파를 검출하고 단일 비트 세그먼트를 추출하였다. 이후 부정맥 신호의 특징을 세밀하게 추출하도록 8개의 합성곱 계층으로 구성하고 이를 LSTM의 입력으로 사용한 후 가중치를 학습시키고 검증 데이터로 모델을 평가한 후 정상 및 부정맥 분류의 변화를 확인하였다. 제안한 방법의 타당성 검증을 위해 MIT-BIH 부정맥 데이터베이스를 사용하여 정확도(accuracy), 정밀도(precision), 재현율(recall), F1 스코어가 사용되었다. 성능평가 결과, 정확도, 정밀도, 재현율, F1 스코어는 각각 92.3%, 90.98%, 92.20%, 90.72%의 우수한 분류율을 나타내었다.

• 한국정보통신학회논문지
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• 제26권10호
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• pp.1490-1499
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• 2022

부정맥이란 심장이 불규칙한 리듬이나 비정상적인 심박동수를 갖는 것을 말하며, 뇌졸중, 심정지 등을 유발하거나 사망에도 이를 수 있는 만큼, 조기 진단과 관리가 무엇보다 중요하다. 본 연구에서는 심전도 신호의 QRS 특징 추출에 적합한 CNN과 기존 LSTM의 직전 패턴의 수렴 한계를 해결할 수 있는 BLSTM을 연결한 CNN-BLSTM 결합 모델을 이용한 부정맥 분류 방법을 제안한다. 이를 위해 먼저 전처리 과정을 통해 잡음을 제거한 심전도 신호에서 QRS 특징점을 검출하고 단일 비트 세그먼트를 추출하였다. 이때 데이터의 불균형 문제를 해결하기 위해 GAN 오버샘플링 기법을 적용하였다. 이 후 합성곱 계층을 통해 부정맥 신호의 패턴을 정밀하게 추출하도록 구성하고 이를 BLSTM의 입력으로 사용한 후 매개변수를 학습시키고 검증 데이터로 학습 모델을 평가한 후 부정맥 분류의 정확도를 확인하였다. 제안한 방법의 우수성을 입증하기 위해 MIT-BIH 부정맥 데이터베이스를 이용하여 분류의 정확도, 정밀도, 재현율, F1-score를 비교하였다. 성능평가 결과 각각 99.30%, 98.70%, 97.50%, 98.06%로 우수한 분류율을 나타내는 것을 확인할 수 있었다.

• Journal of Chest Surgery
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• 제23권2호
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• pp.213-221
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• 1990

We have experienced 62 cases of modified Fontan operations in Seoul Nat’l University Hospital from Apr. 1986 to Jul. 1989, They were 38 males and 24 females, and their age was ranged from 16 months to 15.5 years of age. [mean age : 5.73$\pm$2.99 years] There were 16 operative deaths and 2 late deaths, therefore 29% of overall mortality. Their diagnoses were as follows; 28 single ventricle, 11 tricuspid atresia, 6 DORV with LV hypoplasia, 3 pulmonary atresia with hypoplastic RV, 3 TGA with hypoplastic RV, 3 cor\ulcornerGA with hypoplastic LV and PA, 6 AV canal defects with PA, and 2 others. Low cardiac output and pleural effusion were developed frequently, so we divide 40 patients into some groups to analyze the physiologic and anatomic causes of them. By the degree of the LCO, group A was no LCO[mean amount of inotropics used: 0-5 \ulcornerg/kg/min] with 17 cases, B mild LCO [5-10] with 11, C moderate to severe LCO but alive[>10] with 8, D severe LCO to death with 4 cases. For the pleural effusion, group 1 was to be removed the chest tube within 1 week with 8 cases, group II within 3 weeks with 21 cases, group III beyond 3 weeks with 12 cases. We considered their age, diagnosis, pulmonary artery size[PA index], pulmonary artery abnormality, palliative shunt, systemic ventricular type, pulmonary artery wedge pressure, as preoperative factors, and operative methods, and as postoperative factors, CVP, LAP, arrhythmia, thrombosis, atrioventricular valvular insufficiency, etc. In the view of LCO, pulmonary artery size and PCWP were statistically significant [P<0.05], and arrhythmia, A-V valve insufficiency were inclined to the group C and D Pleural effusion was influenced by the pulmonary artery size, pulmonary artery resistance, PCWP, and CVP significantly. [P<0.05] And arrhythmia, residual shunt, and A-V valvular insufficiency were inclined to group II and III, too. As a results, the followings are to be reminded as the important factors at the care of post-Fontan LCO, and persistent pleural effusion [1] pulmonary artery size, [2] pulmonary artery resistance, [3] PCWP, [4] CVP, [5] arrhythmia, [6] residual shunt, [7]A-V valvular insufficiency.

• Journal of Chest Surgery
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• 제24권2호
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• pp.153-160
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• 1991

Tetralogy of Fallot was repaired by a transatrial-transpulmonary approach in 91 of 250 patients treated surgically [including redo operations] between April 1986 and December 1989. Their age ranged from 6 months to 14 years [mean 39.7 months]. Associated cardiovascular anomalies were right aortic arch [n=22], ASD [n=12], PDA [n=5], persistent left SVC [n=5], and others [n=6]. PA index was measured pre-operatively since 1987 to estimate pulmonary artery size and safe total correction[mean 289$\pm$110mm2/BSA]. Eight patients received previous shunt take down procedure concomitantly. Pulmonary arteriotomy was extended through small pulmonary annulus to a minimal distance upon the right ventricular infundibulum and transannular patch was applied in 38 patients [41.3%], in 31 of them monocuspid patch was utilized. pRV/LV was measured at operation room in 77 patients [mean 0.58$\pm$0.36]. Operative mortality was 6.6% [6/91]. The causes of death were low cardiac output [n=5], arrhythmia[n=1] and respiratory failure [n=1]. At follow-up between 12 months and 57 months [mean 30.8 months] most patients were in New York Heart Association class I without cardiac medication. There was no late death, but reoperations were required in 3 patients to relieve residual right ventricular outflow obstruction. Thus successful repair of tetralogy of Fallot can be accomplished in most patients including infants by transatrial-transpulmonary approach and the better result can be anticipated with respect to postoperative right ventricular function and arrhythmia than the conventional transventricular approach.

• Journal of Chest Surgery
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• 제26권8호
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• pp.613-619
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• 1993

As developing surgical techniques and postoperative cares, a pneumonectomy is a relatively popular surgical method in disease which is not treated completely with other type of pulmonary resection, but a postpneumonectomy complication is a life-threatening serious problem if it occurred. We performed one hundred twenty-five cases of pneumonectomy for treatment of various causes of pulmonary diseases in Kosin Medical College during about ten years, and we experienced 41 cases of postoperative complications in 29 patients, so we analyzed them. The most common complication is an empyema thoracis in 13 cases[10.4%], of which one case combined with bronchopleural fistula died on early postoperative day. Of them except one case, the early postoperative empyema thoracis[within 30 days] were 6 cases, and the late postoperative empyema thoracis[above 30 days] were 6 cases. The main etiologic pathogens were a staphylococcus in early postoperative empyema and a streptococcus in late postoperative empyema, but the most cases were mixed infections with pseudomonas, klebsiella, acinectobacter, and candida. The treatment of postoperative empyema thoracis were that 4 cases were treated with open drainage using chest tube, 7 cases with Clagett`s operation, and 1 case with thoracoplasty. The next common complication was a postoperative serious respiratory insufficiency in 7 cases. And the other complications were massive postoperative bleeding in 5 cases, of which 2 cases advanced to occurrence of postoperative empyema thoracis, and wound disruption in 4 cases, cardiac arrhythmia in 3 cases, contralateral pneumothorax and pneumonia in each of 2 cases, esophagopleural fistula in 1 case. The postoperative deaths were 9 cases[7.2%] of 125 cases, the causes of death were respiratory insufficiency in 6 cases, sepsis in 2 cases, and cardiac arrhythmia in 1 case.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2000년도 추계학술대회 논문집
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• pp.81-87
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• 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.