• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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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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• v.23 no.1
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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.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.1
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• pp.16-22
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• 2010

Electrocardiogram(ECG) analysis and arrhythmia recognition are critical for diagnosis and treatment of ill patients. Cardiac arrhythmia is a condition in which heart beat may be irregular and presents a serious threat to the patient recovering from ventricular tachycardia (VT) and ventricular fibrillation (VF). Other arrhythmias like atrial premature contraction (APC), Premature ventricular contraction (PVC) and superventricular tachycardia (SVT) are important in diagnosing the heart diseases. This paper presented new method to classify various arrhythmias contrary to other techniques which are limited to only two or three arrhythmias. ECG is decomposed into Intrinsic Mode Functions (IMFs) by Empirical Mode Decomposition (EMD). Burg algorithm was performed on IMFs to obtain AR coefficients which can reduce the dimension of feature vector and utilized as Multi-class SVM inputs which is basically extended from binary SVM. We chose optimal parameters for SVM classifier, applied to arrhythmias classification and achieved the accuracies of detecting NSR, APC, PVC, SVT, VT and VP were 96.8% to 99.5%. The results showed that EMD was useful for the preprocessing and feature extraction and multi-class SVM for classification of cardiac arrhythmias, with high usefulness.

• Journal of Chest Surgery
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• v.25 no.2
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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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• v.19 no.2
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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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• v.56 no.6
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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.

• Proceedings of the Korean Biophysical Society Conference
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• 2001.06a
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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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• v.31 no.11
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• pp.1056-1062
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• 1998

Background: We prospectively investigated types, incidences, and risk factors for arrhythmias after open heart surgery in adults. Materials and methods: From June 1994 to May 1995, we performed 302 cases of adult cardiac surgery at our department. This study group consisted of 150 men and 152 women, with a mean age of 43.9±28.0(range 16 to 75)years. We included all the patients irrespective of their operative types or disease entities. Results: The overall incidence of arrhythmias after open heart surgery in adults was 58.3%. The incidence of postoperative arrhythmias for redo-valvular heart surgery was 77.8%, and those for simple valvular procedure, coronary artery bypass surgery, aortic surgery, and congenital heart disease were 70.8%, 45.3%, 40.0%, and 29.5%, respectively. Eight out of twelve risk factors showed statistical significance for the development of postoperative arrhythmias. They were preoperative history of arrhythmias, antiarrhythmic drug medication, previous cardiac surgery, larger left ventricular end-diastolic, end-systolic dimension, left atrial dimension on preoperative echocardiogram, longer cardiopulmonary bypass time and aortic cross clamping time. Univariated analyses for age and types of cardioplegic solution did not show statistical significance. Conclusions: Prospective study on postoperative arrhythmias occurrence, treatment and prevention of is warrauted to draw more clear conclusion.

• The Korean Journal of Physiology and Pharmacology
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• v.6 no.1
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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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• v.53 no.6
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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.