• Journal of Internet Computing and Services
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• v.10 no.2
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• pp.179-186
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• 2009

This paper presents an approach to classify normal and Ventricular Tachycardia/Ventricular Fibrillation(VT/VF) from the Creighton University Ventricular Tachyarrhythmia DataBase(CUDB) using the neural network with weighted fuzzy membership functions(NEWFM). In the first step, wavelet transform is used for producing input values which are used in the next step. In the second step, two numbers of input features are extracted by phase space reconstruction method and peak extraction method using coefficients produced by wavelet transform in the previous step. NEWFM classifies normal and VT/VF beats using two numbers of input features, and then the accuracy rate is 90.13%.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.473-474
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• 2007

본 연구는 체내 이식형 Pacemaker를 연구하면서 심장 질환을 Therapy 해 주는 방법에 대해 저전력 및 성능향상에 중점을 두고 연구 및 실험을 하였다. 우선적으로 심장의 심박동을 연산량이 적은 Peak_detection에서 체크하여 전력소모를 줄이고 나오는 각 심실 및 심방의 Interval을 Disease_episode 에서 받는다. 여기서 5가지 심실 및 심방에 관한 질환들 (VF : Ventricular Fibrillation, VT : Ventricular Tachycardia, FVT : Fast Ventricular Tachycardia, FAT_AF : Fast Atrial Tachycardia/Atrial Fibrillation, AT_AF : Atrial Tachycardia AT_AF : Atrial Fibrillation)을 판별한 후 각 병증에 맞는 Therapy 값을 출력하게 하였다. 그 외에 남아있는 병증에 대해서도 Therapy가 저전력 및 성능향상 되도록 설계하였다. 기존에 적용되어 있는 Detection 기법에서는 각각의 병증에 대해서 각 Detection이 있어 VF와 VT 사이에 있는 FVT와 같은 병증을 치료할 때 FVT 같은 경우에는 VF와 VT사이에 있는 질병이기 때문에 FVT_VF 및 FVT_VT와 같이 각각의 Detection을 두어 전력 소모가 있었다. 심장에서는 여러 질병이 한번에 나을 수 없다는 것에 착안하여 (심박동 Interval에 의해 질병이 판단되므로) 다른 병증이지만 같은 진단 기준을 쓰는 Detection을 통합함으로써 하나의 모듈로 구성하여 Gate수를 줄이고 저전력을 구현하였다. 또한 병증을 판별하는 진단 기준 모듈 중 Onset_Criterion 재설계하여 좀더 성능 향상에 중점을 두었다.

• The Journal of the Korea Contents Association
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• v.9 no.7
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• pp.19-26
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• 2009

This paper presents an approach to classify normal and ventricular tachycardia/fibrillation(VT/VF) from the Creighton University Ventricular Tachyarrhythmia Database(CUDB) using the neural network with weighted fuzzy membership functions(NEWFM) and wavelet transforms. In the first step, wavelet transforms are used to obtain the detail coefficients at levels 3 and 4. In the second step, all of detail coefficients d3 and d4 are classified into four intervals, respectively, and then the standard deviations of the specific intervals are used as eight numbers of input features of NEWFM. NEWFM classifies normal and VT/VF beats using eight numbers of input features, and then the accuracy rate is 90.1%.

• Journal of Yeungnam Medical Science
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• v.34 no.2
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• pp.208-215
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• 2017

Background: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a cardiomyopathy characterized by predominant right ventricular fibro-fatty replacement, right ventricular dysfunction and ventricular arrhythmias. It is a rare but important cause of sudden cardiac death in children and young adults. A meta-analysis on risk stratification of major ventricular tachyarrhythmic events indicating the need for implantable cardioverter defibrillator therapy in ARVC was performed. Methods: The pubmed database was searched from its inception to May 2015. Of the 433 citations identified, 12 were included in this meta-analysis. Data regarding major ventricular tachyarrhythmic events were retrieved in 817 subjects from the studies. For the variables, a combined odds ratio (OR) was calculated using a fixed-effects meta-analysis. Results: Extensive right ventricular dysfunction (OR, 2.44), ventricular late potential (OR, 1.66), inducible ventricular tachyarrhythmia during electrophysiology study (OR, 3.67), non-sustained ventricular tachycardia (OR, 3.78), and history of fatal event/sustained VT (OR, 5.66) identified as significant risk factors (p<0.0001). Conclusion: This meta-analysis shows that extensive right ventricular dysfunction, ventricular late potential, inducible ventricular tachyarrhythmia during electrophysiological study, non-sustained ventricular tachycardia, and history of sustained ventricular tachycardia/fibrillation are consistently reported risk factors of major ventricular tachyarrhythmic events indicating implantable cardioverter defibrillator therapy in patients with ARVC.

• 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.29 no.6
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• pp.639-645
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• 1996

A 14-year-old male patient with previous surgical repair of tetralogy of Fallot was admitted with hemodynamically significant ventricular tachycardia (VT). On preoperative electrophysiologic study (EPS), the morphology of documented VT was RBBB of vertical axis with 320 msec cycle length. The endocardial mapping during VT delineated the origin of VT at right ventricular outflow tract (RVOT), where the patch was attached. The clinical VT had a clockwise reentry circuit around the patch with the earliest activation at the same site seen during the preoperative EPS. The previously placed right ventricular outflow patch and fibrous tissue were removed. During a postoperative EPS, it was no longer possible to induce the VT. Ventricular tachycardia following repair of tetralogy of Fallot seen in this patient was caused by a macro-reentry around the right ventricular outflow patch. We were able to ablate the VT with the aid of a detailed mapping of its epicardial activation sequence.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.11 no.3
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• pp.204-210
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• 2011

This paper proposes a fuzzy support vector machine ($FSVM_n$) pattern classifier to classify the arrhythmia patterns of an electrocardiograph (ECG). The $FSVM_n$ is a pattern classifier which combines n-dimensional fuzzy membership functions with a slack variable of SVM. To evaluate the performance of the proposed classifier, the MIT/BIH ECG database, which is a standard database for evaluating arrhythmia detection, was used. The pattern classification experiment showed that, when classifying ECG into four patterns - NSR, VT, VF, and NSR, VT, and VF classification rate resulted in 99.42%, 99.00%, and 99.79%, respectively. As a result, the $FSVM_n$ shows better pattern classification performance than the existing SVM and FSVM algorithms.

• Journal of Veterinary Clinics
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• v.6 no.2
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• pp.281-290
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• 1989

To gain insight into the relationship between the occurrence of occlusive arrhythmia(OA) and the incidence of reperfusion arrhythmia(RA), this study used 25 open-chest dogs anesthetized with halothan, these were ligated between anterior ventricular branch and marginal branch of left circumflex artery for 30 minutes and occlusive arrhythmia were observed during the ligation. After releasing of the ligation, TA were observed during 5 minutes. The results were summerized as follow； 1. Such arrhythmias as ventricular fibrillation(VF), short run type VPC Premature contraction(VPC), Venticular tachycardia(VT), ventricularc and trigeminy VPC(TVPC) were observed during occlusion and reperfusion. 2. The cases occurred VT, SRVPC and TVPC during occlusion necessarily were Incidence of RA. 3. RA never occurred without appearence of occlusive arrhythmias. 4. The occurrence rate of OA showed 55.5% in the incidence group of RA and 24.6％ in the non incidence group of RA. 5. The occurrence rate of VPC during occlusion showed 9.9＋5.85(episode/min) in the incidence group of RA and 4.46＋5.88(episode/min) in the non-incidence group of RA. These results may be estimated that the occurrence of VT, SRVPC and TVPC, and the high occurrence rate of VPC during occlusion can be predicted the incidence.

• Korean Journal of Clinical Pharmacy
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• v.6 no.2
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• pp.32-40
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• 1996

The electrophysiological effects of benzopyran potassium channel openers (PCOs: lemakalim, KR-30450 and KR-30818) on the ischemia/reperfusion-induced arrythmias were investigated. In anesthetized rats, subjected to 45 min occlusion of the left anterior descending coronary artery (LAD) followed by 90 min reperfusion, ventricular arrythmias were identified according to the Lambeth Conventions by lead II ECG. Rats were intravenously given vehicle ($1\%$ DMSO), lemakalim, KR-30450, and KR-30818 alone or in combination with a selective $K_{ATP}$ blocker glibenclamide, 30 min prior to coronary occlusion. Compared to vehicle, lemakalim ($30{\mu}g/kg$ i.v.), the active enantiomer of cromakalim, had a tendancy to increase the duration of ventricular tachycardia (Vl) and ventricular fibrillation (VF), the number of premature ventricular complexes (PVC) and the incidence of VF, especially in the early post-occlusion peroid ($0\~15$ min), while increasing ST-segment elevation. Both KR-30450 ($30{\mu}g/kg$, i.v.) and KR-30818 (30, $100{\mu}g/kg$, i.v.) showed similar proarrhythmic effects to lemakalim (PVC, duration of VT, and incidence of VF) with a tendancy to decrease the duration of VF and ST-segment elevation. Unlike other PCOs, however, glibenclamide (0.3, 1.0 mg/kg) had opposite effects on the induction of arrhythmias (PVC, the duration of VF); it had a tendancy to increase the duration of VT with a slight elevation of ST-segment. It seems likely that glibenclamide (0.3 mg/kg, i.v.), reduced the effects of lemakalim or KR-30450 ($30{\mu}g/kg$, i.v.) on arrhythmias (PVC, VT, VF and ST-segment). These results indicate that, in the coronary occluded rat model of ischemia, lemikuiln and KR-30450 exert a proarrhythmic activity, the effect being considered related to the opening of KATP channel.

• 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.