• 대한약학회:학술대회논문집
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• 대한약학회 2001년도 Proceedings of the Pharmaceutical Society of Korea
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• pp.128.1-128.1
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• 2001

• 전자공학회논문지SC
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• 제49권3호
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• pp.38-46
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• 2012

심방세동은 발작성 심방세동 단계에서부터 검출 및 분석하여 적절한 치료를 실시하여야 하며, 홀터 심전계를 통해서만 측정할 수 있다. 현재 12채널 심전계를 통해서는 심방세동 신호를 추출할 수 있는 효과적인 방법들이 개발되어 있으나, 홀터 심전계를 위한 방법으로는 심실활동 템플릿을 단순 제거하는 ABS(averaged beat subtraction)방법이 사용되고 있다. 최근 단일 채널 심전도로부터 심방세동 신호를 추출하기 위한 PCA(principal component analysis) 또는 SVD(singular value decomposition) 기반의 알고리즘이 제안되기도 하였으나, 구현이 복잡하고 전문가의 개입이 필요한 한계가 있다. 본 논문에서는 주 입력인 심방세동 심전도에서 심실활동을 이벤트로서 검출한 뒤 이를 기준 입력으로 하는 이벤트 동기 적응필터(ESAF, event-synchronous adaptive filter)를 제안하고, 심방세동 신호 추출 성능을 평가해 보았다. 그 결과 기존 ABS 방법에 비해 우수할 뿐만 아니라, 전문가의 개입 없이도 PCA 또는 SVD 기반의 알고리즘과도 대등한 성능을 보였다. 나아가 이형성 심실활동이 있는 경우에도 효과적으로 대응할 수 있는 확장 ESAF 방법을 제안하였으며, 단형성 심실활동이 있는 경우와 유사한 수준의 성능을 확인하였다. 제안된 알고리즘을 홀터 심전계에 적용하면 발작성 심방세동 심전도의 분석뿐만 아니라 항부정맥 약물의 치료효과를 실시간으로 보다 정확하게 평가할 수 있을 것으로 기대된다.

• Journal of Preventive Medicine and Public Health
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• 제53권1호
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• pp.56-63
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• 2020

Objectives: The objective of this study was to determine the effect of atrial fibrillation (AF) on the risk of dementia in the Korean elderly. Methods: A 10-year retrospective cohort study was conducted using the National Health Insurance Service-Senior Cohort database. We excluded those who were under 65 years of age as of January 2006 (n=46 113), those who were diagnosed with dementia between 2002 and 2005 (n=9086), and those with a history of stroke prior to AF diagnosis (n=8392). We used a Cox proportional hazards model with a time-varying covariate to determine whether AF is associated with the risk of dementia after adjusting for potential confounders. Results: In univariable Cox regression, the hazard ratio (HR) of dementia according to AF status was 1.28 (95% confidence interval [CI], 1.23 to 1.33). After adjusting for potential confounders, AF was found to increase the risk of dementia (HR, 1.12; 95% CI, 1.07 to 1.17), Alzheimer dementia (HR, 1.12; 95% CI, 1.07 to 1.17), and vascular dementia (HR, 1.10; 95% CI, 1.03 to 1.18). In patients diagnosed with AF, the incidence of dementia was lower (HR, 0.50; 95% CI, 0.47 to 0.52) in patients who were treated with oral anticoagulants. Conclusions: Investigating the potential risk factors of dementia in an aged society is important. We found a slightly higher risk of dementia in those with AF than in those without AF, and we therefore concluded that AF is a potential risk factor for dementia.

• 한국산업정보학회논문지
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• 제20권3호
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• pp.61-69
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• 2015

본 논문에서는 이산 웨이블릿 변환을 통해 추출된 시간 영역과 주파수 영역의 특징들을 활용하여 심박수변이도를 확률적인 지식으로 분석할 수 있는 방법을 제안하였다. 제안된 방법에서 지식획득 알고리즘은 규칙생성과 규칙평가 단계로 구성되어 있으며, 규칙생성에서는 ROC 분석을 통해 수치적인 속성값을 이산화된 구간으로 변환하고, 서로 다른 의사결정값을 포함하는 구간들 사이에 일관성 정도를 비교함으로써 감축된 규칙-집합을 생성한다. 이때 규칙-집합 내에 각 규칙에 대해서 확률적 해석을 위한 3가지 척도를 추정하였다. 제안된 모형의 효과성은 심혈관질환 병력을 가진 58명의 심전도 데이터로부터 심방세동을 식별할 수 있는 5가지 규칙을 생성하였고, 이들 규칙의 분별력을 평가하였다. 실험결과, 제안된 모형으로부터 생성된 지식은 4가지 성능평가 척도에 대해서 각각 93%의 정확도를 보여주었다.

• 한국정보통신학회논문지
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• 제15권12호
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• pp.2655-2663
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• 2011

지금까지 심방세동을 검출하는 방법은 P파의 형태, 시간 주파수 영역 분석법이 주를 이루었다. 하지만 P파는 잡음의 영향을 많이 받는 환경에서는 검출의 정확도가 떨어지며, 시간 주파수 영역 분석법은 RR 간격에 따라 변화하는 불규칙적 리듬에 관한 정보를 정확하게 얻지 못하는 단점이 있다. 본 연구에서는, P파의 형태는 고려하지 않고, 불규칙 RR 간격 리듬의 비선형적 특성 분석을 통한 심방세동 검출 알고리즘을 제안한다. 이를 위해 불규칙 RR 간격 리듬을 다양성, 무작위성, 복잡성으로 각각 정의하고 제곱평균제곱근(RMSSD), 전환점비(TPR), 표본 엔트로비(SpEn)의 3가지 비선형적 특성 분석을 통하여 심방세동을 분류하였다. 제안된 알고리즘의 검출 성능을 평가하기 위해 3가지 통계치의 최적값을 설정하고 MIT-BIH 심방세동 데이터베이스와 부정맥 데이터베이스를 이용하여 실험하였다. 성능 평가 결과, MIT-BIH 심방세동 데이터베이스에 대해서는 민감도(sensitivity:94.5%), 특이도(specificity:96.2%)를 각각 나타내었으며, 부정맥 데이터베이스에 대해서는 민감도(89.8%), 특이도(89.62%)를 각각 나타내었다.

• 한국임상약학회지
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• 제26권3호
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• pp.207-212
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• 2016

Objective: Prescription rate of dabigatran and rivaroxaban, which are the direct oral anticoagulants (DOAC), has increased. We have analyzed the prescription trend and medication use of dabigatran and rivaroxaban in patients with non-valvular atrial fibrillation (NVAF). Methods: It was retrospectively studied from September 2012 to April 2014 using the electronic medical records and the progress notes. Patients with NVAF (n=424) were evaluated on the medication use, prescribing preferences, adverse drug reactions (ADRs) and the availability of prescription reimbursement of dabigatran (n=210) and rivaroxaban (n=214). Results: Dabigatran was prescribed higher than rivaroxaban (23.3% versus 7.5%, p<0.001) in the neurology department, but rivaroxaban was prescribed higher compared to dabigatran in the cardiology department (87.4% versus 74.3%, p<0.001). Dabigatran was prescribed more than rivaroxaban in high risk patients with CHADS2 score ${\geq}3$ (44.3% versus 31.3%, p=0.006). Dabigatran patients seemed to have more ADRs than patients with rivaroxaban (25.2% versus 11.2%, p<0.001), but no serious thrombotic events and bleeding were found. Only 35.6% (n=151) were eligible for prescription reimbursement by the National Health Insurance (NHI). Bridging therapy (86, 31.5%) and direct-current cardioversion (57, 20.2%) were main reasons of ineligibility for reimbursement. Conclusion: Prescription preferences were present in choosing either dabigatran or rivaroxaban for patients with NVAF. Inpatient protocols and procedures considering patient-factors in NVAF need to be developed.

• Journal of Yeungnam Medical Science
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• 제34권2호
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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.

• 한국산업정보학회논문지
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• 제20권6호
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• pp.37-46
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• 2015

The wireless electrocardiographic monitoring system(WDMS) is designed to be long term monitoring for the early detection of cardiac disorders. The current version of the WDMS can identify two types of cardiac rhythms in real-time, such as atrial fibrillation(AF) and normal sinus rhythm(NSR), which are very important to track cardiac-rhythm disorders. In this study, we proposed the analysis method to discriminate the characteristics statistically evaluated in both time and frequency domains between AF and NSR using various parameters in the heart rate variability(HRV). And we applied various ECG detection methods (e.g., difference operation method) and compared the results with those of the discrete wavelet transform(DWT) method. From the statistically results, we found that the parameters such as STD RR, STD HR, RMSSD, NN50, pNN50, RR Trian, and TNN(p<0.05) are significantly different between the AF and NSR patients in time domain. On the other hand, the frequency domain analysis results showed a significant difference in VLF power($ms^2$), LF power($ms^2$), HF power($ms^2$), VLF(%), LF(%), and HF(%). In particular, the parameters such as STD RR, RMSSD, NN50, pNN50, VLF power, LF power and HF power were considered as the most useful parameters in both AF and NSR patient groups. Our proposed method can be efficiently applied to early detection of abnormal conditions and prevent the such abnormals from becoming serious.

• International Journal of Arrhythmia
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• 제18권2호
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• pp.66-76
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• 2017

Background and Objectives: Although an anterior linear ablation is an effective lesion set in radiofrequency catheter ablation (RFCA) for longstanding persistent atrial fibrillation (L-PeAF), its durability for bidirectional block (BDB) is only about 60% at repeat procedure. We hypothesized that changes in electrocardiogram (ECG) may predict an anterior line block state and the clinical outcome of L-PeAF ablation. Subjects and Methods: We studied 304 L-PeAF patients (77% male, $60{\pm}10yrs$), who consistently underwent RFCA Dallas lesion set (circumferential pulmonary vein isolation, posterior box lesion, and anterior line) protocol with subsequent comparison of pre-procedural and post-procedural P wave axes, and one year follow-up (n=205) sinus rhythm (SR) ECGs. Results: 1. P wave axis shifted inferiorly at immediate post-procedure (p<0.001), and was independently correlated with BDB of anterior line (${\ss}=10.4$, 95% confidence interval [CI] 2.79-17.94, p=0.008). 2. The degree of post-procedural inferior shift of P wave axis did not reflect clinical recurrence within one-year (n=205, p=0.923), potentially due to conduction recovery of an anterior line. However, among 160 patients without clinical recurrence within one-year, P wave axis at one-year ECG was independently associated with very late recurrence of AF after one-year (n=160, hazard ratio [HR] 0.98; 95% CI 0.97-0.99, p=0.001), during $45.6{\pm}16.7$ months of follow-up. 3. Among 22 patients who underwent repeat procedures, P wave axis shift was more significant in patients with maintained BDB of an anterior line than in those without (p=0.015). Conclusion: An inferior shift of P wave axis reflects the achievement and the maintenance of an anterior line BDB, and is associated with better long-term clinical outcome after catheter ablation for L-PeAF based on Dallas lesion set.

• Tuberculosis and Respiratory Diseases
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• 제84권1호
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• pp.35-45
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• 2021

Globally, cardiovascular diseases and chronic obstructive pulmonary disease (COPD) are the leading causes of the non-communicable disease burden. Overlapping symptoms such as breathing difficulty and fatigue, with a lack of awareness about COPD among physicians, are key reasons for under-diagnosis and resulting sub-optimal care relative to COPD. Much has been published in the past on the pathogenesis and implications of cardiovascular comorbidities in COPD. However, a comprehensive review of the prevalence and impact of COPD management in commonly encountered cardiac diseases is lacking. The purpose of this study was to summarize the current knowledge regarding the prevalence of COPD in heart failure, ischemic heart disease, and atrial fibrillation. We also discuss the real-life clinical presentation and practical implications of managing COPD in cardiac diseases. We searched PubMed, Scopus, EMBASE, and Google Scholar for studies published 1981-May 2020 reporting the prevalence of COPD in the three specified cardiac diseases. COPD has high prevalence in heart failure, atrial fibrillation, and ischemic heart disease. Despite this, COPD remains under-diagnosed and under-managed in the majority of patients with cardiac diseases. The clinical implications of the diagnosis of COPD in cardiac disease includes the recognition of hyperinflation (a treatable trait), implementation of acute exacerbations of COPD (AECOPD) prevention strategies, and reducing the risk of overuse of diuretics. The pharmacological agents for the management of COPD have shown a beneficial effect on cardiac functions and mortality. The appropriate management of COPD improves the cardiovascular outcomes by reducing hyperinflation and preventing AECOPD, thus reducing the risk of mortality, improving exercise tolerance, and quality of life.