Showing papers by "Manuel J. Antunes published in 2006"

Guidelines on the management of valvular heart disease The Task Force on the Management of Valvular Heart Disease of the European Society of Cardiology

Abstract: Guidelines and Expert Consensus Documents aim to present management recommendations based on all of the relevant evidence on a particular subject in order to help physicians select the best possible management strategies for the individual patient suffering from a specific condition, taking into account the impact on outcome and also the risk–benefit ratio of a particular diagnostic or therapeutic procedure. Numerous studies have demonstrated that patient outcomes improve when guideline recommendations, based on the rigorous assessment of evidence-based research, are applied in clinical practice. A great number of Guidelines and Expert Consensus Documents have been issued in recent years by the European Society of Cardiology (ESC) and also by other organizations or related societies. The profusion of documents can put at stake the authority and credibility of guidelines, particularly if discrepancies appear between different documents on the same issue, as this can lead to confusion in the minds of physicians. In order to avoid these pitfalls, the ESC and other organizations have issued recommendations for formulating and issuing Guidelines and Expert Consensus Documents. The ESC recommendations for guidelines production can be found on the ESC website.1 It is beyond the scope of this preamble to recall all but the basic rules. In brief, the ESC appoints experts in the field to carry out a comprehensive review of the literature, with a view to making a critical evaluation of the use of diagnostic and therapeutic procedures and assessing the risk–benefit ratio of the therapies recommended for management and/or prevention of a given condition. Estimates of expected health outcomes are included, where data exist. The strength of evidence for or against particular procedures or treatments is weighed according to predefined scales for grading recommendations and levels of evidence, as outlined in what follows. The Task Force members of the writing panels, …

Detection of S1 and S2 heart sounds by high frequency signatures

Abstract: A new unsupervised and low complexity method for detection of S1 and S2 components of heart sound without the ECG reference is described The most reliable and invariant feature applied in current state-of-the-art of unsupervised heart sound segmentation algorithms is implicitly or explicitly the S1-S2 interval regularity. However; this criterion is inherently prone to noise influence and does not appropriately tackle the heart sound segmentation of arrhythmic cases. A solution based upon a high frequency marker; which is extracted from heart sound using the fast wavelet decomposition, is proposed in order to estimate instantaneous heart rate. This marker is physiologically motivated by the accentuated pressure differences found across heart valves, both in native and prosthetic valves, which leads to distinct high frequency signatures of the valve closing sounds. The algorithm has been validated with heart sound samples collected from patients with mechanical and bio prosthetic heart valve implants in different locations, as well as with patients with native valves. This approach exhibits high sensitivity and specificity without being dependent on the valve type nor their implant position. Further more, it exhibits invariance with respect to normal sinus rhythm (NSR) arrhythmias and sound recording location.

Wavelet transform and simplicity based heart murmur segmentation

Abstract: This paper is aimed at the identification of the boundaries of murmur present in heart sound. Heart murmurs provide crucial diagnosis information for several heart diseases such as natural or prosthetic valve dysfunction and heart failure. In order to find the valuable information about abnormal heart behavior, segmentation of the heart murmurs has to be performed. In this work we solve this problem using the wavelet decomposition- simplicity filter. In this algorithm, simplicity of the wavelet decomposed heart sound signal is measured and adaptively thresholded in order to discriminate S1/S2 sounds from murmurs. The method has been tested with stenosis and regurgitation (aortic, mitral, pulmonary, tricuspid) heart sounds and 89.10% sensitivity and 95.50 % specificity have been achieved.

A New Algorithm for Detection of S1 and S2 Heart Sounds

Abstract: This paper presents a new algorithm for segmentation and classification of S1 and S2 heart sounds without ECG reference. The proposed approach is composed of three main stages. In the first stage the fundamental heart sound lobes are identified using a fast wavelet transform and the Shannon energy. Next, these lobes are validated and classified into S1 and S2 classes based on Mel-frequency coefficients and on a non supervised neural network. Finally, regular heart cycles are identified in a post-processing stage by a heart rhythm criterion. This approach was tested using sound samples collected from prosthetic valve implanted patients. Results are comparable with ECG based approaches.

Mitral valve repair: better than replacement

Abstract: For the majority of surgeons, mitral valve repair has become the method of choice for surgical correction of mitral regurgitation. However, the feasibility of repair depends not only on the pathology but also on the experience of the surgeon and/or team. Success rates may reach almost 100% in the most common form of isolated prolapse of the middle scallop of the posterior leaflet. Nevertheless, mitral repair is still subject to a pronounced, sometimes painful, learning curve. The durability of the repair also depends on the type of pathology and on many other factors, including the technique used. Since its inception in the 1970s, the techniques of mitral valve repair have been the subject of many modifications and improvements which have made it a more predictable and reproducible method. One area where much improvement was made was ischaemic regurgitation, which was initially considered refractory to repair and for which there is now a growing experience and much improved results. Also, advancements have occurred in the treatment of regurgitation related to cardiomyopathy, previously considered a contraindication for repair. By contrast, repair for rheumatic disease still carries the worst results, although the characteristics of the usually underdeveloped and young population may still make it preferable to mitral valve replacement. In this work, we analyse the state of the art of mitral valve repair and its results according to our experience and in the light of recent reports. After an initial period of distrust, in the late 1970s and early 1980s, when it was developed mainly through the efforts of Carpentier,1 Duran,2 and others, mitral valve repair has since become a generally accepted alternative to prosthetic replacement for surgical treatment of virtually all forms of mitral valve disease; indeed, most surgeons now recognise its superiority, in terms of both early and late …

Searching for Similarities in Nearly Periodic Signals With Application to ECG Data Compression

Abstract: This paper proposes a new methodology to identify and correlate patterns on nearly periodic signal, based on signal simplification and clustering approaches. Using cubic Bezier curves some significant signal samples (control points), enabling to segment adequately the original signal, are extracted in a first step. Next, given the correlation among extracted control points, the detection of similarities within the overall signal is then performed through a clustering technique. Although the approach is useful for many types of signals, the compression of electrocardiogram signals (ECG) is here investigated. Results with standard MIT-BIH databases show promising compression ratios, in particular, high compression ratios are found for long duration signals, when the signal presents strong regularities

Pleomorphic adenoma of the trachea. Case report

Abstract: The authors present a case of a pleomorphic adenoma of the trachea, diagnosed during the clinical evaluation of a suspected COPD or lung cancer in a heavy smoker patient with a positive family history of oncologic diseases. The patient underwent segmental resection of the trachea with complete excision of the tumour, and a good prognosis is anticipated.

ESC statement Postępowanie z chorymi po operacjach zastawek serca Stanowisko Europejskiego Towarzystwa Kardiologicznego

Abstract: Co roku w Europie przeprowadza sie ok. 50 000 zabiegow wszczepienia sztucznych zastawek serca i prawie tyle samo zabiegow naprawczych. Poprzednie zalecenia ESC dotyczące postepowania po operacjach zastawek serca opublikowano w 1995 r. Ich przedmiotem byla jednak tylko profilaktyka przeciwzakrzepowa [1]. Zalecenia amerykanskie, szerzej omawiające zagadnienia diagnostyki i leczenia chorob zastawkowych, ogloszono drukiem w 1998 r., jednak poświecono w nich stosunkowo niewiele uwagi postepowaniu z chorymi po zabiegach kardiochirurgicznych [2]. Ponizszy dokument stanowi wspolne stanowisko komitetu redakcyjnego, w sklad ktorego weszli przedstawiciele nastepujących trzech grup roboczych Europejskiego Towarzystwa Kardiologicznego: ds. zastawkowych wad serca, ds. zakrzepicy oraz ds. rehabilitacji i fizjologii wysilku fizycznego. W przypadku wiekszości zagadnien związanych z postepowaniem po zabiegach na zastawkach niemozliwe jest oparcie sie na wynikach badan klinicznych z randomizacją czy metaanalizach, poniewaz badan takich praktycznie nie prowadzono. Bardzo nieliczne proby kliniczne z randomizacją są malo przydatne w odniesieniu do szerokiej grupy chorych, poniewaz oceniano w nich bardzo wyselekcjonowane populacje chorych o malej liczebności, a roznorodnośc metodologii i charakterystyki grup badanych sprawia, ze ich metaanaliza jest niemozliwa. Dlatego tez prezentowane zalecenia prawie w calości opierają sie na wynikach badan bez randomizacji oraz odpowiednich badaniach w naukach podstawowych.

Adenoma pleomórfico da traqueia. Caso clínico

Abstract: Resumo Os autores apresentam o caso de um doente com um adenoma pleomorfico da traqueia, diagnosticado no contexto da avaliacao clinica de doenca pulmonar obstrutiva cronica ou neoplasia broncopulmonar, tendo em conta a dimensao dos seus habitos tabagicos e a historia familiar positiva para patologia oncologica. O doente foi submetido a resseccao segmentar da traqueia com excisao total do tumor, antevendo- -se bom prognostico.