• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.496-497
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• 2008

In this study, we present the computational analysis of cardiac arrhythmias that is the major cause of human sudden cardiac death. First, electric excitation and condution in one dimensional cardiac tissue model is solved and the results on condution block are represented. In two dimensional model, vortex daynamics in cardiac tissue is analyzed to delineate the breakup phenomenon inducing ventricular fibrillation. We also simulated a three dimenional heart model to see the vortex breakup and explained the mechanism in physiological aspect.

• Journal of Dental Anesthesia and Pain Medicine
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• 제23권1호
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• pp.45-51
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• 2023

Andersen-Tawil syndrome (ATS) is a rare genetic disease characterized by a triad of episodic flaccid muscle weakness, ventricular arrhythmias, and physical anomalies. ATS patients have various cardiac arrhythmias that can cause sudden death. Implantation of an implantable cardioverter-defibrillator (ICD) is required when life-threatening cardiac arrhythmias do not respond to medical treatment. An 11-year-old girl underwent surgery for an ICD implantation. For general anesthesia in ATS patients, anesthesiologists should focus on the potentially difficult airway, serious cardiac arrhythmias, such as ventricular tachycardia (VT), and delayed recovery from neuromuscular blockade. We followed the difficult airway algorithm, avoided drugs that can precipitate QT prolongation and fatal cardiac arrhythmias, and tried to maintain normoxia, normocarbia, normothermia, normoglycemia, and pain control for prevention of sympathetic stimulation. We report the successful application of general anesthesia for ICD implantation in a pediatric patient with ATS and recurrent VT.

• 한국정보통신학회논문지
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• 제14권1호
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• pp.16-22
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• 2010

심전도 신호 분석 및 부정맥 분류는 환자를 진단하고 치료하는데 중요한 역할을 한다. 부정맥은 맥박이 불규칙한 상태로 심실빈맥(VT)이나 심실세동(VF) 환자에게 심각한 위협이 될 수 있다. 심방조기수축(APC)과 상심실성빈맥(SVT), 심실조기수축(PVC)은 심실빈맥(VT)만큼 치명적이지는 않지만 심장질환을 진단하는데 중요한 부정맥이다. 본 논문은 2~3개의 부정맥 분류만을 고려한 기존의 방법을 극복하고 다양한 부정맥을 분류하기 위한 새로운 방법을 제시한다. 심전도 신호의 특징 추출을 위해서 EMD 방법으로 신호를 분해하여 IMFs를 얻는다. 입력 데이터의 양은 분류기 성능에 영향을 미치므로 신호 데이터의 차원을 감소시키기 위해 Burg 알고리즘을 IMFs에 적용하여 AR 계수를 구하고 여러 개의 이진 분류기를 결합한 다중 클래스 SVM의 입력으로 사용한다. 최적의 SVM 성능 파라미터를 선택하고 부정맥 분류에 적용한 결과 검출의 정확성은 96.8%~99.5%였다. 실험 결과는 제안한 EMD 방법에 의한 전처리 및 특징 추출과 다중 클래스 SVM에 의한 부정맥 분류의 유용성을 보여준다.

• Journal of Chest Surgery
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• 제25권2호
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• pp.188-193
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• 1992

Life-threatening cardiac arrhythmia is a frequent complication of open heart surgery. There are many causes of postoperative cardiac arrhythmias. Electrolyte imbalance such as hypokalemia and acidemia are major causes of ventricular arrhythmias. Infrequently, however, antiarrhythmic agents and /or hypomagnesemia induce[s] a ventricular arrhythmia such as "torsade de pointes" by increasing the repolarization time of myocardium, Recently, we have experienced two cases of "Torsade de pointes" associated with hyp-omagnesemia after replacement of mitral valve and one of whom after use of procainamide. Intravenous infusion of magnesium immediately and successfully abolished the torsade de pointes in both cases.intes in both cases.

• 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%.

• Journal of Chest Surgery
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• 제56권6호
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• pp.414-419
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• 2023

Background: The recurrence of ventricular arrhythmias (VAs) in patients who have already undergone treatment with antiarrhythmic medication, catheter ablation, and the insertion of implantable cardioverter defibrillators is not uncommon. Recent studies have shown that bilateral cardiac sympathetic denervation (BCSD) effectively treats VAs. However, only a limited number of studies have confirmed the safety of BCSD as a viable therapeutic option for VAs. Methods: This single-center study included 10 patients, who had a median age of 54 years (interquartile range [IQR], 45-65 years) and a median ejection fraction of 58.5% (IQR, 56.2%-60.8%), with VAs who underwent video-assisted BCSD. BCSD was executed as a single-stage surgery for 8 patients, while the remaining 2 patients initially underwent left cardiac sympathetic denervation followed by right cardiac sympathetic denervation. We evaluated postoperative complications, the duration of hospital stays, and VA-related symptoms before and after surgery. Results: The median hospital stay after surgery was 2 days (IQR, 2-3 days). The median surgical time for BCSD was 113 minutes (IQR, 104-126 minutes). No significant complications occurred during hospitalization or after discharge. During the median follow-up period of 13.5 months (IQR, 10.5-28.0 months) from surgery, no VA-related symptoms were observed in 70% of patients. Conclusion: The benefits of a short postoperative hospitalization and negligible complications make BCSD a safe, alternative therapeutic option for patients suffering from refractory VAs.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2001년도 학술 발표회 진행표 및 논문초록
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• pp.17-17
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• 2001

It is well known that myocardial stretch causes changes in electrical signalling and contractility of the heart. For example, mechanical stretch depolarises the membrane potential of cardiac cells and alters the shape of action potentials. As a result, these effects either accelerate the frequency of heart rate or induce arrhythmias of the heart.(omitted)

• Journal of Chest Surgery
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• 제31권11호
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• pp.1056-1062
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• 1998

연구배경 : 개심술 후의 부정맥은 빈번하게 발생하는 합병증이며 그 종류도 다양할 뿐 아니라, 수술후 발생하는 부정맥은 심박출량의 저하 등 심각한 결과를 초래할 가능성이 있다. 재료 및 방법 : 본 연구는 이러한 부정맥의 예방과 치료의 방침을 결정하는데 기본적인 자료를 제공하고자 1994년 6월부터 1995년 5월까지 1년간 서울대학교병원 흉부외과에서 개심술을 시행 받은 성인 환자들을 대상으로 술후 부정맥의 양상을 전향적으로 분석하여 위험인자를 유추하였다. 결과 : 총 302명을 대상으로 하였는데, 그 중 남자가 150명이었고 여자는 152명이었으며, 평균 연령은 43.9세 (16세부터 75세까지) 였다. 대상환자 모두 술전 및 술후 표준 12-lead EKG 및 중환자실에서의 24시간 심전도 감시장치로 부정맥을 진단하였으며 수술직후 집중감시병동에서는 동맥혈 가스분석 및 혈중 potassium 농도를 측정하여 이상이 있으면 교정하였고 단순히 산혈증이나 저칼륨혈증에 의한 부정맥은 연구대상에서 제외하였다. 술후 부정맥의 전체 발생률은 58.3%이었는데, 판막 재수술의 경우 부정맥이 77.8%에서 나타났고, 단순 판막 수술, 관상동맥 우회술, 대동맥 수술, 선천성 심기형의 수술후의 부정맥 발생률들은 각각 70.8%, 45.3%, 40.0%, 29.5% 이었다. 연령별 발생은 의미있는 차이를 보이지 않았으며 심정지액의 종류도 의미있는 차이는 보이지 않았다. 반면에 수술의 종류, 술전 부정맥의 유무, 체외순환 및 대동맥 차단시간, 그리고 술전 시행한 심초음파상의 좌심실 확장기말과 수축기말 내경, 좌심방의 내경 등은 부정맥의 발생률과 통계적으로 유의한 상관관계를 보여주었다 (p< 0.05). 결론 : 향후 질병, 수술방법 등이 균질화된 집단을 선정하여 전향적인 연구를 진행함으로써 개심술후 부정맥의 발생, 치료 및 예방에 관한 보다 정확한 결론에 접근할 수 있을 것으로 생각한다.

• The Korean Journal of Physiology and Pharmacology
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• 제6권1호
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• pp.1-7
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• 2002

Congenital Long QT syndrome (LQTs) is a relatively rare pathologic disorder but results frequently in sudden cardiac death. Of the six LQTs that have been clinically described, five have been worked out for their genetic and biophysical profile. Most are generated by mutations which cause a loss of function in two delayed $K^+$ currents, $i_{Ks}\;and\;i_{Kr}.$ One syndrome is generated by mutations in the $Na^+$ channel which causes essentially a gain of function in the channel. Clinically the syndromes are characterized by slowed repolarization of the cardiac ventricular action potential and the occurrence of typical arrhythmias with undulating peaks in the electrocardiogram, called Torsade de Pointes. Arrhythmias are initiated by early or delayed afterdepolarizations and continue as reentry. Triggers for cardiac events are exercise (swimming; LQT1), emotion (arousal; LQT2) and rest/sleep (LQT3). ${\beta}-blockers$ have a high efficacy in the treatment of LQT1 and LQT2. In LQT3 their use is questionable. The study of congenital LQTsyndromes is a remarkable example of how basic and clinical science converge and take profit of each other's contribution.

• Clinical and Experimental Pediatrics
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• 제53권6호
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• pp.680-687
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• 2010

Patients with congenital heart diseases (CHD) are confronted with early- and late-onset complications, such as conduction disorders, arrhythmias, myocardial dysfunction, altered coronary flow, and ischemia, throughout their lifetime despite successful hemodynamic and/or anatomical correction. Rhythm disturbance is a well-known and increasingly frequent cause of morbidity and mortality in patients with CHD. Predisposing factors to rhythm disturbances include underlying cardiac defects, hemodynamic changes as part of the natural history, surgical repair and related scarring, and residual hemodynamic abnormalities. Acquired factors such as aging, hypertension, diabetes, obesity, and others may also contribute to arrhythmogenesis in CHD. The first step in evaluating arrhythmias in CHD is to understand the complex anatomy and to find predisposing factors and hemodynamic abnormalities. A practical stepwise approach can lead to diagnosis and prompt appropriate interventions. Electrophysiological assessment and management should be done with integrated care of the underlying heart defects and hemodynamic abnormalities. Catheter ablation and arrhythmia surgery have been increasingly applied, showing increasing success rates with technological advancement despite complicated arrhythmia circuits in complex anatomy and the difficulty of access. Correction of residual hemodynamic abnormalities may be critical in the treatment of arrhythmia in patients with CHD.