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1

Detection of sudden cardiac death by a comparative study of heart rate variability in normal and abnormal heart conditions

Rohila Ashish, Sharma Ambalika

Biocybernetics and Biomedical Engineering

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2020

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Vol. 40, no. 3

1140--1154

EN

Background and objective: Sudden cardiac death (SCD) is an unexpected loss in functioning of the heart. It generally occurs within 1 h of onset of symptoms. No reliable method for early detection of SCD is available. Therefore, the development of a non-invasive method for risk identification remains a topic of utmost interest. This paper presents a novel approach for detection of the risk of SCD by performing a comparative analysis of heart rate variability (HRV) in normal subjects as well as patients with coronary artery disease and heart failure. Methods: HRV of four subject groups, normal sinus rhythm, coronary artery disease, congestive heart failure, and SCD, has been analyzed. The analysis was performed by using nonlinear techniques and time-frequency representation obtained by generalized S-transform. The extracted features were examined for their clinical significance by using the Kruskal–Wallis one-way analysis of variance and multiple comparisons. Eventually, classification was performed using support vector machines and decision tree classifiers to separate the individuals at risk of SCD. Results: The performance of the proposed methodology has been evaluated using PhysioNet open-access databases. Statistical analysis shows that HRV in SCD group differs significantly from other groups. For classification, an accuracy of 91.67% was achieved with 83.33% sensitivity, 94.64% specificity, and 84.75% precision. Conclusion: The experimental results obtained by analyzing retrospective data seem promising. However, the methodology needs to be tested on larger databases to generalize the findings. Prospective studies on its clinical usefulness may help in developing a concrete diagnostic technique.

2

A Novel Approach for Coronary Artery Disease Diagnosis using Hybrid Particle Swarm Optimization based Emotional Neural Network

Shahid Afzal Hussain, Singh M. P.

Biocybernetics and Biomedical Engineering

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2020

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Vol. 40, no. 4

1568--1585

EN

Coronary artery disease (CAD) can cause serious conditions such as severe heart attack, heart failure, and angina in patients with cardiovascular problems. These conditions may be prevented by knowing the important symptoms and diagnosing the disease in the early stage. For diagnosing CAD, clinicians often use angiography, however, it is an invasive procedure that incurs high costs and causes severe side effects. Therefore, the other alternatives such as data mining and machine learning techniques have been applied extensively. Accordingly, the paper proposes a recent development of a highly accurate machine learning model emotional neural networks (EmNNs) which is hybridized with conventional particle swarm optimization (PSO) technique for the diagnosis of CAD. To enhance the performance of the proposed model, the paper employs four different feature selection methods, namely Fisher, Relief-F, Minimum Redundancy Maximum Relevance, and Weight by SVM, on Z-Alizadeh sani dataset. The EmNNs, with addition to the conventional weights and biases, uses emotional parameters to enhance the learning ability of the network. Further, the efficiency of the proposed model is compared with the PSO based adaptive neuro-fuzzy inference system (PSO-ANFIS). The proposed model is found better than the PSO-ANFIS model. The obtained highest average values of accuracy, precision, sensitivity, specificity, and F1-score over all the 10-fold cross-validation are 88.34%, 92.37%, 91.85%, 78.98%, and 92.12% respectively which is competitive to the known approaches in the literature. The F1-score obtained by the proposed model over Z-Alizadeh sani dataset is second best among the existing works.

3

Classification of coronary artery diseased and normal subjects using multi-channel phonocardiogram signal

Samanta Pranab, Pathak Akanksha, Mandana Kayapanda, Saha Goutam

Biocybernetics and Biomedical Engineering

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2019

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Vol. 39, no. 2

426--443

EN

Coronary artery disease (CAD) is one of the leading causes of mortality and morbidity. There is a need to develop a simple, reliable, and non-invasive screening tool to diagnose CAD. Prior studies reported that turbulent blood flow due to stenosed coronary arteries causes weak CAD murmurs. Analysis of phonocardiogram (PCG) signals can be useful to detect these murmurs. In this work, we propose a new multi-channel PCG-based system to classify CAD-affected and normal subjects, and it does not require any additional reference signal, such as an electrocardiogram (ECG) signal. The proposed system simultaneously acquires PCG signals from four different auscultation sites on the chest. It extracts five different features from time and frequency domains of the PCG signals. The two-class classification is done in a machine learning framework by employing an artificial neural network (ANN) classifier. The classification performances are evaluated for each channel as well as for their combinations. Experimental results show that the proposed sub-band-based spectral features perform well for both clean and noisy data. An accuracy of 82.57% is obtained using the combination of the signals acquired from tricuspid, mitral, and midaxillary regions. The multi-channel system gives more than 4% relative improvement over the best performance obtained by its single-channel counterpart, and the proposed features outperform earlier used features.

4

Entropies for automated detection of coronary artery disease using ECG signals: A review

Acharya U. R., Hagiwara Y., Koh J. E. W., Oh S. L., Tan J. H., Adam M., Tan R. S.

Biocybernetics and Biomedical Engineering

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2018

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Vol. 38, no. 2

373--384

EN

Coronary artery disease (CAD) develops when coronary arteries are unable to supply oxygen-rich blood to the heart due to the accumulation of cholesterol plaque on the inner walls of the arteries. Chronic insufficient blood flow leads to the complications, including angina and heart failure. In addition, acute plaque rupture may lead to vessel occlusion, causing a heart attack. Thus, it is encouraged to have regular check-ups to diagnose CAD early and avert complications. The electrocardiogram (ECG) is a widely used diagnostic tool to study the electrical activity of the heart. However, ECG signals are highly chaotic, complex, and non-stationary in their behaviour. It is laborious, and requires expertise, to visually interpret these signals. Hence, the computer-aided detection system (CADS) is developed to assist clinicians to interpret the ECG signals fast and reliably. In this work, we have employed sixteen entropies to extract the various hidden signatures from ECG signals of normal healthy persons as well as patients with CAD. We observed that the majority of extracted entropy features showed lower values for CAD patients compared to normal subjects. We believe that there is one possible reason which could be the decreased in the variability of ECG signals is associated with reduced heart pump function.

5

Metody oceny rezerwy wieńcowej

Gawryś K., Gawryś J., Majchrzak K.

Inżynier i Fizyk Medyczny

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2016

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Vol. 5, nr 6

335--341

PL

Rezerwa wieńcowa, będąca różnicą pomiędzy spoczynkowym a maksymalnym przepływem wieńcowym, a także cząstkowa rezerwa przepływu są przydatnymi parametrami w ocenie pacjentów z chorobą wieńcową i ich kwalifikacji do leczenia zachowawczego bądź rewaskularyzacyjnego. Pośrednie metody oceny rezerwy wieńcowej – próby ergometryczne pozwalają m.in. na ocenę zdolności krążenia wieńcowego do dostarczania odpowiedniej ilości tlenu w sytuacji zwiększonego zapotrzebowania. Do oceny perfuzji mięśnia sercowego i rezerwy wieńcowej wykorzystuje się także skalę TIMI (Thrombolysis in Myocardial Infarction) i jej modyfikacje przydatne w prognozowaniu rokowania u chorych z ostrym zawałem serca oraz w ocenie efektów leczenia reperfuzyjnego, rezonans magnetyczny pozwalający dodatkowo na zbadanie innych parametrów funkcjonalnych serca, SPECT (Single-photon Emission Computed Tomography), PET (Positron Emission Tomography), a także nowoczesne skanery PET-CT i SPECT-CT.

EN

Coronary reserve, defined as the difference between resting and maximum coronary flow, as well as the fractional flow reserve are useful parameters in the evaluation of patients with coronary artery disease and their qualifications to conservative or invasive treatment. Indirect methods of coronary reserve assessment – ergometric tests, allow to assess the capacity to deliver enough amount of oxygen in the case of increased demand. To assess myocardial perfusion and coronary reserve are also used: TIMI (Thrombolysis in Myocardial Infarction) scale – useful in predicting prognosis in patients with acute myocardial infarction and in evaluating the effects of reperfusion therapy, magnetic resonance imaging which allows also to explore other functional parameters of the heart, SPECT (Single-Photon Emission Computed Tomography), PET (Positron Emission Tomography) and modern scanners – PET-CT and SPECT-CT.

6

The attempt of the blood vessel contractibility estimation on the basis of the computed tomography imaging

Porwik P., Sosnowski M., Wróbel K., Wesołowski T.

Journal of Medical Informatics & Technologies

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2011

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Vol. 17

173--181

EN

Cardiovascular mortality remains a leading health and social problem in many countries throughout the world. Its main cause is related to atherosclerosis of coronary and cerebral vessels with their most severe consequences: heart attack and stroke. Therefore, it is obvious that current preventive measures include early detection of atherosclerosis process. Multi-detector computed tomography (MDCT) is one of imaging modalities allowing for noninvasive detection of atherosclerotic lesion within coronary arteries in subjects with accumulation of risk factors (smoking, high lipids, hypertension, male gender, family history) or with suspicion of coronary artery disease (CAD). In is very important that the tomographic images are taken in synchronization with cardiac cycle so that, during few heartbeats, an appropriate series of images can be recorded. Commonly, cardiac MDCT is used for visualization of cardiac and vessels morphology. Heart function can also be determined, however, this MDCT potential is only rarely applied, as current echocardiographic modalities are sufficient. Functional analysis of coronary arteries (flow, reserve) is usually approached by means of invasive procedures. We aimed at finding solution for evaluation of another kind of functional analysis of coronary arteries, namely vessel's wall compliance by means of MDCT coronary angiography. Under the proposed procedure, on basis of serial CT images of the vessels over entire cardiac cycles, the internal area of the blood vessel is measured and its changes during various phases of heartbeat (systole, diastole) are calculated. If the vessel wall has been changed by atherosclerotic plaque, either calcified or non-calcified, then its compliance will be reduced due to its stiffness. Calculation of coronary artery compliance requires a series of measurements, which is unreliable and impractical for doing manually. One component of the method described herein involves the images being converted into binary representations and the Hough Transform then applied. The overall methodology proposed in this paper assists in the preparation of a medical diagnosis.

7

Steady and disturbed flow effects on human umbilical vein endothelial cells (HUVECs) in vascular system: an experimental study

Arslan N., Isik S., Uykan O.

Acta of Bioengineering and Biomechanics

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2010

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Vol. 12, no. 4

3-9

EN

Coronary artery disease is still one of the most important reasons of the death in the world. The endothelium is the membrane of special cells which lines the interior surface of blood vessels forming an interface between circulating blood in the lumen and the rest of the vessel wall. Endothelial cells (ECs) line the entire circulatory system, from the heart to the smallest capillary. ECs dysfunction has been linked with atherosclerosis through their response to fluid forces. ECs change their morphology when exposed to mechanical stresses. The morphological responses include reorientation, elongation, and rearrangement of adhering molecules. Atherosclerotic lesions are formed in specific arterial regions, where low and oscillatory endothelial shear stress (ESS) occur. In this study, the effects of steady and disturbed flow over human umbilical vein endothelial cells (HUVECs) at different flow rates and periods were determined. Steady flow experiments were performed at flow rate of 1000 cm3/min for twenty four hours. Disturbed flow experiments simulating the flow in branching regions of arterial systems were carried out at flow rates of 250 cm3/min for five hours. The results obtained testified to the morphological changes easily observed. The directional alignment of the cells was determined in the steady flow experiments. Under disturbed flow conditions we observed not only the cell movement at the stagnation point but also the polygonal cell shape downstream the flow field.

8

Zastosowanie tomografii komputerowej w kardiologii - praca przeglądowa

Kuniej T., Derkacz A.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

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2009

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Vol. 15, nr 3

273-276

PL

rozdzielczością przestrzenną i czasową oraz z przyspieszeniem akwizycji, pozwolił na wiarygodne obrazowanie serca i naczyń wieńcowych. Klasyczna angiografia pozostaje złotym standardem w wykrywaniu zwężenia naczyń wieńcowych, jednakże wymagania terapeutyczne wymuszają poszukiwanie mniej inwazyjnych metod diagnostycznych. Wielorzędowa tomografia komputerowa jest nieinwazyjną metodą obrazowania, pozwalającą na diagnostykę chorób serca, naczyń wieńcowych oraz zmian patologicznych, takich jak na przykład restenoza w pomostach naczyń wieńcowych czy stentach, zatorowość płucna lub tętniak rozwarstwiający aorty, które są trudne do wykrycia za pomocą innych technik.

EN

In recent years, improvements in multislice computed tomography in terms of spatial and temporal resolution, as well as short acquisition time have enabled reliable diagnostics of the heart and coronary arteries. Conventional coronary angiography is valuable method for the detection of coronary stenosis, however due to the requirements of many therapeutic procedures, there is an increasing demand for less invasive diagnostic methods. Multislice CT is a noninvasive imaging modality suitable to detect many cardiac and coronary and extracardiac pathologies, like e.g. by-pass and stent restenoses, pulmonary embolism or aortic dissection that are difficult to detect by any other modality.

9

Zastosowanie technik telemetrycznych do transmisji sygnału EKG w kardiologii

Nowicki P., Biały D., Mazurek W.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

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2007

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Vol. 13, nr 1

16-17

PL

Rozwój sieci telefonii cyfrowej umożliwia szybkie przesyłanie danych w postaci cyfrowej. Większość współczesnych urządzeń, w tym stosowanych medycynie, jak tomografy komputerowe czy aparaty EKG, ma możliwość zapisania danych w postaci cyfrowej. Zastosowanie technologii telemetrycznych w medycynie (tzw. telemedycyna) umożliwia wykonanie badania i przesłanie wyników celem analizy i diagnozy do wyspecjalizowanego ośrodka z doświadczoną kadrą. Coraz częściej przesyłane są zdjęcia rentgenowskie (te-leradiologia). W telekardiologii przesłane są m.in. zapisy EKG lub USG. We współczesnym społeczeństwie najczęstszą przyczyną zgonów są choroby układu sercowo-naczyniowego. Zawał mięśnia serca jako najgroźniejsza postać choroby wieńcowej jest śmiertelny w 25-30%, a obecnie stwierdza się około 100 tysięcy przypadków zawału rocznie w Polsce. Udowodniono w badaniach wieloośrodkowych, że najważniejszymi czynnikami rokowniczymi są przywrócenie drożności naczynia wieńcowego zamkniętego w przebiegu zawału i czas do rozpoczęcia leczenia. Metody przywracania drożności tętnicy to: an-gioplastyka wieńcowa i leczenie trombo-, fibrynolityczne. Skrócenie czasu do rozpoczęcia leczenia jest możliwe dzięki zastosowaniu telekardiologii - przesłanie EKG bezpośrednio z karetki i w przypadku rozpoznania zawału transport chorego bezpośrednio do specjalistycznego ośrodka dysponującego pracownią hemodynamiki, wykonującą zabiegi angioplasty ki. W pracy opisano systemy i techniki przesyłania danych, ze szczególnym uwzględnieniem telemetrii EKG.

EN

The development of GSM network enables fast transmission of data. Many medical diagnostics devices allow for recording data in digital format. Telemetry enables data transmission to remote center with experienced staff. X-ray images or ECG signals may be transmitted. Cardiovascular diseases are most common cause of death in modern societies. About 30% of patients with myocardial infarction die during first 2 days. In Poland, there are ca. 100.000 cases of myocardial infarction each year. Restorations of blood supply in region of infarction and the time from onset of disease to start of treatment are most important factors influencing prognosis. There are two preferred methods of treatment: coronary angioplasty and thrombolytic therapy. Transmission of ECG signals directly from ambulance and immediate patient transport to clinics may shorten the time between diagnosis and medical intervention.

10

System rehabilitacji kardiologicznej PELETON plus

Brandt J., Świda K.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

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2007

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Vol. 13, nr 3

210-211

PL

Jak stwierdzono w "Raporcie o stanie rehabilitacji kardiologicznej w Polsce", liczba chorych z rozpoznaną chorobą wieńcową jest szacowana na 1,5-2,5 miliona. Można zaobserwować występowanie coraz większej liczby ostrych zespołów wieńcowych (OZW) - zarówno wśród ludzi w podeszłym wieku, wynikające ze starzenia się społeczeństwa, jak i wśród osób w średnim wieku. Zwiększa się więc liczba chorych, którzy po przebyciu OZW mogą zostać wyłączeni z aktywnego życia. Szansę na przywrócenie im sprawności psychofizycznej stwarza rehabilitacja kardiologiczna. Zostało wykazane, że właściwie prowadzona rehabilitacja kardiologiczna może zmniejszyć umieralność z przyczyn sercowo-naczyniowych i ogólną o 20-25%, oraz liczbę nagłych zgonów w pierwszym roku po przebytym zawale o 35%. Rehabilitacja kardiologiczna podnosi również wydolność fizyczną, wpływając tym samym na poprawę jakości życia.

11

Neural net vs. minimum distance classifier : choice of an intelligent computer tool or the diagnosis of the coronary artery disease based on ECG exercise tests

Lewenstein K.

Elektronika : konstrukcje, technologie, zastosowania

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2004

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Vol. 45, nr 8-9

104-105

EN

Choice of an intelligent tool for computer-aided diagnosis of the coronary artery disease on the basis of the ECG exercise test has been the subject of the paper. Results of application different models of neural networks as feedforward perceptions, Fahlman's network and RBF network in comparison to minimum-distance classifiers built according the k-nearest neighbours and set's space covering rules, created without and with using feature selections have been presented in the paper. Correctness of the patient state diagnosis pointing the particular narrowing in coronary vessel for the best neural model has been equal 95% and for presented below traditional classifier came to 99,8%. It means that traditional not as popular method could sometimes be better.

PL

Przedmiotem pracy jest wybór inteligentnego narzędzia do komputerowego wspomagania diagnostyki choroby wieńcowej. W pracy przedstawiono wyniki zastosowań różnych modeli neuronowych a mianowicie: jednokierunkowych, wielowarstwowych sieci typu perceptronowego, trenowanych wg metody wstecznej propagacji błędu, sieci Fahlmana i sieci o Radialnych Funkcjach Bazowych w porównaniu do klasyfikatorów minimalno-odległościowych, tworzonych baz i z selekcją cech, zgodnie z metodami k-najbliższych sąsiadów i metodą pokrywania się zbiorów. Trafność diagnozy z dodatkowym wskazaniem szczegółowej lokalizacji zwężenia dla najlepszego modelu neuronowego wyniosła 95% a dla klasyfikatora 99,8%. Okazało się, że klasyczna, stara i nie tak współcześnie popularna metoda może być skuteczniejsza.

12

Electronic patient record, expert system and mobile monitoring in Cardio.net project

Rudowski R., Grabowski M., Sierdziński J., Guć M.

Biocybernetics and Biomedical Engineering

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2004

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Vol. 24, no. 1

61-71

EN

Cardio.net project is aimed at the implementation of the prototype system of telecardiology in Mazovia and Pomerania Regions of Poland. It is planned as a tool to reduce the time from the onset of symptoms to the cardiological intervention, which can significantly reduce the mortality of patients with the acute coronary syndromes (ACS). The system will enable teleconsultations, from the reference centers to the regional hospitals, regarding the need for invasive cardiological intervention. If there is such a need then the patient will be transported to the reference center. The Cardio.net tasks include the design of telecommunication infrastructure, incorporating data transmission standards HL7, DICOM, work on the security and safety of the system, the design of Electronic Patient Record (EPR), uniform archive of EPR's and also the expert system. The EPR consist of two types of forms: a) personal data forms, b) forms supporting the physician work (case history, diagnosis, physical examination, the clinical course of hospitalization, additional tests and drugs). The tools used for creating EPR and archive of EPR's were PHP, Java Script, XML and MySQL. The risk stratification and therapeutic decision making in ACS are the main tasks of the expert system. There are two main therapeutic strategies: early invasive versus conservative. The chosen strategy depends on several factors. The expert system has been verified on the archival data of 147 patients with ACS. In 127 (86%) the expert system suggested the same strategy as applied by the cardiologist. In conclusion: uniform EPR and archive of EPR's give a chance of improving the quality of the cardiological care due to teleconsultations performed directly by specialists or indirectly by the expert system. Mobile monitoring and alerting can decrease the time from the onset of symptoms to the therapeutic intervention thus improving the patients safety,

13

Biomechanical characteristics of the stent-coronary vessel system

Paszenda Z., Marciniak J., Będziński R., Rusiński E., Smolnicki T.

Acta of Bioengineering and Biomechanics

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2002

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Vol. 4, nr 1

81-89

EN

The paper presents the biomechanical characteristics of the stent-coronary vessel system defined using the finite element method. Within the framework of the project the stress and strain distributions in the elements of the modelled system were determined for various stent form features, taking into account stent implementation stage and also its operation with the changing blood pressure. The results obtained may be a basis for optimization of the coronary stent shape and its form features, as well as of the properties of metallic material from which stents are made.