• Journal of Biomedical Engineering Research
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• v.39 no.2
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• pp.69-79
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• 2018

The present study proposes an algorithm that can discriminate between normal subjects and paroxysmal atrial fibrillation (PAF) patients, which is conducted using electrocardiogram (ECG) without PAF events. For this, time-domain features and random forest classifier are used. Time-domain features are obtained from Poincare plot, Lorenz plot of ${\delta}RR$ interval, and morphology analysis. Afterward, three features are selected in total through feature selection. PAF patients and normal subjects are classified using random forest. The classification result showed that sensitivity and specificity were 81.82% and 95.24% respectively, the positive predictive value and negative predictive value were 96.43% and 76.92% respectively, and accuracy was 87.04%. The proposed algorithm had an advantage in terms of the computation requirement compared to existing algorithm, so it has suggested applicability in the more efficient prediction of PAF.

• Journal of Biomedical Engineering Research
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• v.23 no.1
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• pp.1-8
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• 2002

Atrial fibrillation(AF). chronic or paroxysmal is the most frequent arrhythmia in human subjects Duration of P wave in signal-averaged electrocardiography(SAECG) reflects intra-atrial conduction time and therefore. could be used as an electrophysiological marker for atrial conduction chance at the earthy stave. So we apply the analysis method using SAECG to diagnose Paroxysmal atrial fibrillation(PAF) . Subjects Participated for the study consisted of two groups: a control group(n=34) of normal healthy volunteers and a group of AF Patients(n=38) with a documented history of PAF but no other history of cardiac disease. We evaluated the effect of several filtering and determination methods to find the starting and ending feints of the P wavy on its duration. To increase the measurement reliability of P wave duration. the automatic detection method was proposed. Also. to increase the detection rate for PAF risk, the decision threshold value was optimized using receiver operation characteristics(ROC) curve. Results showed that the highest statistical difference (p〈0.001) of the P wane duration between controls and subjects was obtained at the Processing condition, using absolute threshold vague(8.75 $\mu N$) , a least mean square(LMS) high pass filter and 30 Hz cutoff frequency. The most outstanding difference(sensitivity 88 % specificity 64.4 %) between controls and subjects was obtained at the decision threshold value of 112 ms.

• Journal of Chest Surgery
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• v.47 no.4
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• pp.358-366
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• 2014

Background: To improve sinus rhythm conversion, the Cox maze III procedure with narrow mazes (width: ${\leq}3.0cm$) was performed in combination with left atrial volume reduction. Methods: From October 2007 to April 2013, 87 patients with atrial fibrillation (paroxysmal in 3, persistent in 14, and permanent in 70) underwent the Cox maze procedure concomitant with another cardiac procedure. They were followed-up with serial electrocardiographic and echocardiographic studies. We used 24-hour Holter monitoring tests to evaluate postoperatively symptomatic patients. Results: At the mean follow-up time of 36.4 months, 81 patients (94.2%) had sinus rhythm and two were on anti-arrhythmic medication (one on a beta-blocker and the other on amiodarone). Five patients (5.8%) with postoperative recurrent and persistent atrial fibrillation never experienced sinus rhythm conversion; however, they did not require any medication for rate control. On postoperative echocardiography, the left atrial A waves were more frequently observed after concomitant mitral valve repair than after concomitant mitral valve replacement (82.4% vs. 40.4%, respectively; p<0.001). Conclusion: For the Cox maze procedure, narrow mazes and atrial volume reduction resulted in excellent sinus rhythm conversion without the preventive use of anti-arrhythmic drugs, and they did not affect the presence of the left atrial A waves on echocardiography.

• Journal of Yeungnam Medical Science
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• v.34 no.2
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• pp.242-246
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• 2017

Acute limb ischemia (ALI) due to an embolism is associated with high mortality rate and poor prognosis, and early diagnosis with prompt revascularization is required to reduce the risk of limb amputation or even death. The etiologies of ALI are diverse, and it includes an embolism from the heart and thrombotic occlusion of the atherosclerotic native vessels, stents, or grafts. An uncommon cause of ALI is acute arterial thromboembolism, and atrial fibrillation (AF) is the single most important risk factors for systemic thromboembolism. It is important to correctly identify the source of ALI for secondary prevention, as it depends on the underlying cause. Percutaneous transluminal angioplasty (PTA) has been proven to be a safe and effective treatment for focal atherosclerotic and thrombotic occlusive diseases of the aorta and its major extremity branches. Herein, we report on a 77-year-old female patient with acute upper limb ischemia, treated by PTA using a catheter-guided thrombectomy. He was newly diagnosed with paroxysmal AF (PAF) while evaluation the cause of his acute arterial thromboembolism. We recommend that cardiologists always consider PAF as a possible diagnosis even in patients without any history of AF under ALI because it is possible to develop thromboembolism in clinical practice.

• Proceedings of the Korean Biophysical Society Conference
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• 2001.06a
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• pp.58-58
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• 2001

Even though atrial fibrillation is the most prevalent arrhythmia, the mechanism of development is not yet clear. Recently, there has been several reports that the most frequent source of paroxysmal atrial fibrillation is located inside pulmonary vein. Recently we successfully isolated single cardiac myocytes which were inside of pulmonary vein and reported the spontaneous action potential was generated from these cells.(omitted)

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.49 no.3
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• pp.38-46
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• 2012

Atrial fibrillation is needed to be detected at paroxysmal stage and to be treated. But, paroxysmal atrial fibrillation ECG is hardly obtained with 12-lead electrocardiographs but Holter systems. Presently, the averaged beat subtraction(ABS) method is solely used to estimate atrial fibrillatory waves even with somewhat large residual error. As an alternative, in this study, we suggested an ESAF(event-synchronous adaptive filter) based algorithm, in which the AF ECG was treated as a primary input and event-synchronous impulse train(ESIT) as a reference. And, ESIT was generated so to be synchronized with the ventricular activity by detecting QRS complex. We tested proposed algorithm with simulated AF ECGs and real AF ECGs. As results, even with low computational cost, this ESAF based algorithm showed better performance than the ABS method and comparable performance to algorithm based on PCA(principal component analysis) or SVD(singular value decomposition). We also proposed an expanded version of ESAF for some AF ECGs with multi-morphologic ventricular activities and this also showed reasonable performance. Ultimately, with Holter systems including our proposed algorithm, atrial activity signal can be precisely estimated in real-time so that it will be possible to calculate atrial fibrillatory rate and to evaluate the effect of anti-arrhythmic drugs.

• Journal of Chest Surgery
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• v.53 no.5
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• pp.270-276
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• 2020

Background: We investigated the impact of previous catheter ablation (CA) on the midterm outcomes of totally thoracoscopic ablation in patients with lone atrial fibrillation (AF). Methods: Between February 2012 and July 2018, 332 patients underwent totally thoracoscopic ablation for the treatment of AF (persistent AF; n=264, 80%). The patients were stratified into CA (n=47, 14%) and non-CA (nCA; n=285, 86%) groups according to their CA history. Results: All the baseline clinical characteristics and risk factors were similar between the groups except for age, percentage of male patients, prevalence of paroxysmal AF, prior percutaneous coronary intervention, and left atrial volume index (LAVI). No significant intergroup differences were observed in the incidence of early and late complications. At late follow-up, normal sinus rhythm was observed in 92% (43 of 47) of the patients in the CA group and 85% (242 of 285) of the patients in the nCA group (p=0.268). The rate of freedom from AF recurrence at 5 years was 55.3%±11.0% in the CA group, which was similar to that in the nCA group (55.7%±5.1%, p=0.690). In Cox regression analysis, preoperative brain natriuretic peptide levels and LAVI were associated with AF recurrence, but CA history was not significant. Conclusion: Totally thoracoscopic ablation was safe and effective in treating AF irrespective of CA history. A history of CA did not appear to affect the procedural complexity.

• Journal of Yeungnam Medical Science
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• v.18 no.2
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• pp.267-276
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• 2001

Background: P wave dispersion(PWD) is defined as the difference between the maximum and minimal P wave duration in any of the 12 leads of the surface ECG. The prolongation of atrial conduction time and the inhomogeneous propagation of sinus impulse are known electrophysiologic features in patients with paroxysmal atrial fibrillation(PAF). The purpose of this study was to determine the role of P wave dispersion for the prediction of PAF and to evaluate the effectiveness of prophylactic antiarrhythmic therapy. Materials and Methods: The study population included 20 patients with a history of idiopathic PAF and 20 age and sex matched healthy control subjects. We measured the maximum P wave duration(P maximum) and P wave dispersion from 12 lead ECG. Results: P maximum and P dispersion in idiopathic PAF were significantly higher than normal control group($97.2{\pm}12$, $48.5{\pm}9$ msec vs, $76.5{\pm}11$, $21{\pm}8$ msec, respectively p<0.001, <0.001). After 12-month follow up period P maximum and P dispersion were significantly reduced than those of initial state($77.2{\pm}13$, $26.4{\pm}9$ msec vs. $97.2{\pm}12$, $48.5{\pm}9$ msec, respectively p<0.001,<0.001). Conclusion: P dispersion and P maximum were significantly different between patients with idiopathic PAF and healthy control group. Those are easily accessible, non-invasive simple electrocadiographic markers that could be used for the prediction and prognostic factors of idiopathic PAF.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.181-182
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• 1998

In previous study for correlation between P-wave Signal Averaged Electrocardiography (SAECG) and Paroxysmal Atrial Fibrillation (PAF) subjects, we showed that the duration of P-wave in subjects is longer than in controls. In this respect, the P-wave SAECG is a new method proving to be an accurate and independent noninvasive marker for the risk of PAF. To prove this suggestion, accurate detection and alignment of P-wave are indispensible. In previous study, we measured P-wave duration by manual. So it was not accurate and consistent. To measure the P-wave duration accurately and automatically, we have developed an automatic algorithm for P-wave duration measurement. We showed that the duration of P- wave in the subjects is longer than in controls with this algorithm.

• International Journal of Arrhythmia
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• v.19 no.3
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• pp.235-284
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• 2018

In this part the writing group will cover strategies, techniques, and endpoints of atrial fibrillation (AF) ablation. Prior to all, electrical isolation of the pulmonary veins is recommended during all AF ablation procedures. In addition, techniques to be used for ablation of persistent and long-standing persistent AF, adjunctive ablation strategies, nonablative strategies to improve outcomes of AF ablation, and endpoints for ablation of paroxysmal, persistent, and long-standing persistent AF will be reviewed. Currently many technologies and tools are employed for AF ablation procedures. Radiofrequency energy, cryoablation, and other energy sources and tools are in various stages of development and/or clinical investigation. Finally, anticoagulation strategies pre-, during, and postcatheter ablation of AF and technical aspects of ablation to maximize safety are discussed in this section.