• 한국음향학회지
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• 제30권3호
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• pp.149-157
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• 2011

본 논문은 support vector machine (SVM)을 사용하여 은닉 마코프 모델 (HMM)과 심잡음 존재 정보를 결합한 새로운 심장질환 분류 방법을 제안한다. 켑스트럼 특징과 HMM 비터비 (Viterbi) 알고리듬을 이용하여 입력 신호를 모든 심장질환 모델에 대하여 상태 단위로 분할하여 상태별로 로그우도 (점수)를 계산한다. 심잡음 신호의 시간적 위치 특성을 이용하기 위하여 입력신호를 두 개의 부대역으로 나누고 부대역별로 프레임 단위의 심잡음 점수를 계산한 다음, 비터비 알고리듬으로부터 구한 상태 분할 정보를 이용하여 상태단위의 심잡음 점수를 구한다. SVM은 모든 심장질환 종류에 대한 상태 단위의 HMM과 심잡음 점수를 입력으로 하여 최종적으로 심장질환을 판정한다. 심장질환 분류 실험결과, 제안한 방법은 기존의 켑스트럼 특징과 HMM 분류기를 이용한 방법에 비하여 20.4 %의 상대적 개선율을 보여준다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -2
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• pp.1045-1048
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• 2000

This paper presents the application of the wavelet transform analysis and the neural network method to the phonocardiogram (PCG) signal. Heart sound is a acoustic signal generated by cardiac valves, myocardium and blood flow and is a very complex and nonstationary signal composed of many source. Heart sound can be discriminated normal heart sound and heart murmur. Murmurs have broader frequency bandwidth than the normal ones and can occur at random position of cardiac cycle. In this paper, we classified the group of heart sound as normal heart sound(NO), pre-systolic murmur(PS), early systolic murmur(ES), late systolic murmur(LS), early diastolic murmur(ED). And we used the wavelet transform to shorten artifacts and strengthen the low level signal. The ANN system was trained and tested with the back- propagation algorithm from a large data set of examples-normal and abnormal signals classified by expert. The best ANN configuration occurred with 15 hidden layer neurons. We can get the accuracy of 85.6% by using the proposed algorithm.

• Journal of Chest Surgery
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• 제23권3호
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• pp.532-536
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• 1990

We experienced surgical correction of 2 cases of discrete membranous subaortic stenosis. Case 1 was 19 years old male patient. His complaints were fatigue, exertional dyspnea, syncope and angina for 8 years. Ejection. systolic murmur was heard at the second right intercostal space and diastolic murmur was heard at the apex. A thrill was palpated over the second right intercostal space and area of the carotid artery. 2-D echo, cardiac cath and left ventriculogram revealed discrete membranous subaortic stenosis and VSD. Complete excision of discrete membrane without mymectomy was done. VSD was closed with dacron patch and aortic valve was replaced with St. Jude medical valve. Case 11 was 16 years old female whose complaints were exertional dyspnea and syncope. Ejection systolic murmur was heard at second right intercostal space, but diastolic murmur was not heard. A thrill was palpated over the second right intercostal space and the area of carotid artery. 2-D echo, cardiac cath and left ventriculogram revealed discrete membranous subaortic stenosis. Complete excision of fibrous tissue and myotomy were made and aortic valve was replaced with St. Jude medical valve. Operative finding was followed: both aortic valves showed deformity of leaflets. Subaortic region had a thickened central fibrous body from which the ridge protruded. Both patient`s postoperative course were uneventful and short-term follow-up results were good except soft systolic murmur at the aortic area.

• 한국멀티미디어학회논문지
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• 제19권3호
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• pp.557-566
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• 2016

Heart sounds generated by the beating heart and blood flow reflect the turbulence created when the heart valves snap shut. Cardiac diagnosis is typically started by an auscultation using a stethoscope, from which a medical doctor, depending on his hearing capabilities and training, listens and interprets the acoustic signal. This method of diagnostic is uncertain, mostly due to the fact that human ear loses the acoustic frequency sensitivity through the years. Even though an auscultation has some weaknesses like uncertainty, it is considered as a primary tool due to its simplicity. In this paper, heart murmur detection algorithm is proposed using time and frequency characteristics of heart sound. The propose heart murmur detection method adapted conventional primary heart sound detection method in time domain and modified spectral flatness method in frequency domain for detecting heart murmurs. From experimental results, it is confirmed that the proposed algorithm detect the heart murmurs efficiently.

• Journal of Chest Surgery
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• 제17권4호
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• pp.780-785
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• 1984

We had studied 20 cases of VSD patients whose murmur was sustained after open heart surgery from 1977 to 1984. The postoperative cardiac catheterization was performed on post-op. 20th day. Their ages ranged from 5 to 25 years old. Among them, 4 patients had significant residual shunt which required reoperation. [1 patient; re-op, 3 patient; refused]. Sex ratio was 13:7 in male and female. Associated anomalies were PDA, ASD, Pulmonary stenosis, Mitral insufficiency. Except 1 case, all of them was Kirklin type II VSD. Postoperative complications were I RBBB, residual shunt, cardiac tamponade due to bleeding, wound infection. Preoperative pulmonary artery systolic pressure was highly related to residual shunt in our study. Postoperative LVEDV returned to normal range on the 3rd week.

• 전자공학회논문지SC
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• 제38권5호
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• pp.59-69
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• 2001

최근에 디지털 선호처리와 전자부품의 발달로 심음 분식에 관한 많은 연구가 진행되고 있다. 그러나 심음 인식, 특히 심음 한주기 전체에 대한 인식연구는 거의 없다. 본 논문에서 심음 전체 한주기에 대한 새로운 인식 방법을 제안하였다. 먼저 주성분 분석을 이용하여 훈련 셋트로 데이터베이스를 구축한다. 데이터베이스는 새로운 심음입력을 인식하는데 이용된다. 심음은 정상심음, 수축전 심잡음, 수축초기 심잡음, 수축 말기 심잡음, 이완 초기 심잡음, 이완 말기 심잡음， 연속적 심잡음으로 분류된다. 실험결과 새로운 인식 방법은 심음의 특징을 인식하는데 효과적이었다. 최대 인식률은 NO의 경우 71%, PS와 ES의 경우 80%, LS의 경우 78%, ED의 경우 87%, LD의 경우 60%, CM의 경우 20% 이었다. 현재의 결과가 실제적으로 심음을 인식하기에는 충분하지 못하였지만 선음 전체 주기를 대상으로 한 연구라는데 의의가 있으며 더 효과적인 데이터베이스를 구축함으로써 인식률을 개선할 수 있다.

• 한국음향학회지
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• 제29권2호
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• pp.133-140
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• 2010

연속 심음신호로부터 추출한 새로운 시간영역에서의 특징들을 추가하여 심장질환 분류의 성능을 개선한다. 기존에 사용되고 있는 켑스트럼 영역 특징인 멜주파수 켑스트럼 계수 (MFCC)에 심음 포락선, 심잡음 확률벡터, 심잡음 진폭값 변동으로 구성된 새로운 3종류의 시간영역 특징을 추가한다. 심장 질환 분류 및 검출 실험에서, 시간영역 특징의 분류 정확도에 대한 기여도를 평가하고 순차적 특징선택 방식을 이용하여 시간영역 특징을 선택한다. 선택된 특징들은 다층 퍼셉트론(MLP), support rector machine (SVM), extreme learning machine (ELM)와 같은 신경회로망 패턴 분류기에 대하여 의미있고 일관되게 분류 정확도를 개선함을 보여준다.

• Journal of Chest Surgery
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• 제23권4호
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• pp.758-763
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• 1990

A congenital fistulous communication between the coronary artery and the cardiac chamber or the pulmonary artery is a rare condition, but increasing cases with this anomaly are being recognized with wide spread use of cardiac catheterization and coronary arteriography. Recently we experienced one case of right coronary artery fistula which was associated with atrial septal defect. The patient was a 24 year old female who was admitted because of cardiac murmur, palpitation and dyspnea on exertion after pregnancy. Cardiac catheterization and selective coronary arteriography revealed that a fistulous communication, forming a large aneurysm, was noted from the right coronary artery emptied into the right ventricle. On the operation field, the right coronary artery was curved and markedly dilated from the aorta to the middle segment at acute margin of the right ventricle. The egg-sized aneurysm of dilated right coronary artery was noticed on right ventricle. The aneurysm was incised longitudinally and both the proximal opening and the termination site of the fistula were closed directly with aneurysmectomy. The right atrium was also opened to evaluate the fistulous termination site and repaired only small interatrial septal defect. Postoperative course was uneventful and she was discharged without problems

• 대한수의학회지
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• 제56권4호
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• pp.261-264
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• 2016

A nine-month-old Pomeranian dog with exercise intolerance and syncope was presented. The dog was depressed with grade 4 systolic murmur on cardiac auscultation. Based on cardiac examination, the dog was diagnosed with severe subaortic stenosis with involvement of the anterior mitral valve. ${\beta}-blocker$ administration was initiated and clinical signs were improved, but not fully resolved. Balloon valvuloplasty was performed and the dog survived for nearly one year without clinical sign and the cardiac troponin I level was normalized. This case describes successful management of severe subaortic stenosis in a small breed dog through balloon valvuloplasty.

• Journal of Chest Surgery
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• 제21권4호
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• pp.716-720
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• 1988

Since Krause first described coronary arteriovenous fistula in 1865, there have been nearly 300 additional patients with this malformation reported in the literature. Increasing numbers of patients with this anomaly are being recognized each year resulting from the widespread use of cardiac catheterization and selective coronary arteriography in the evaluation of a variety of cardiac problems. A 9 month old male was admitted with the chief complaint of cardiac murmur and frequent URI and diagnosed as coronary A-V fistula at the distal portion of left anterior descending coronary artery to the apex of the right ventricle by cardiac catheterization and aortography. On the operative field, the left anterior descending coronary was markedly dilated about 1.5 cm in diameter from the aorta to the apex of the heart. The fistula opening was closed with 5-0 Prolene continuously under cardiopulmonary bypass and moderate hypothermia[28*C]. Postoperative course was uneventful and the patient was discharged without problem.