China
Africa
Explore chapters and articles related to this topic
Heart Valve Dynamics
Published in Joseph D. Bronzino, Donald R. Peterson, Biomedical Engineering Fundamentals, 2019
Choon Hwai Yap, Erin Spinner, Muralidhar Padala, and Ajit P. Yoganathan
MV pathologies encompass a spectrum of lesions, which include congenital defects, degeneration of valve tissue, and geometric distortions to the valve secondary to other diseases. Congenital lesions of the MV include annular calcication leading to mitral stenosis, leaet prolapse due to Marfan syndrome, isolated cle valve, undivided atrioventricular valve in ostium primum or septum secondum defects, and mitral regurgitation due to congestive heart failure caused by severe stenosis of the le main coronary artery. ough the underlying etiology of each congenital lesion is dierent, the common manifestations between all the lesions are leaet and subannular malformations that reduce valve competence. Degenerative MV lesions occur in both children and adults due to genetic mutations such as Marfan syndrome, acquired diseases such as rheumatic heart disease in developing countries, broelastic deciency in adult life due to collagen deciencies, or Barlow’s syndrome speculated to be caused due to genetic and mechanical factors. e last classication of MV lesions, termed as the functional
Collecting and Making Sense of Big Data for Improved Health Care
Published in Ervin Sejdić, Tiago H. Falk, Signal Processing and Machine Learning for Biomedical Big Data, 2018
A benefit of capturing heart sounds as electronic signals is that the analog signal can be converted to streaming digital data points. Through machine learning approaches such as neural networks and support vector machines, the patterns in the data points can be coded as algorithms and used to classify normal and abnormal heart sounds. The algorithms can then be programmed in microchips located in the stethoscope or an attached smartphone. Although in their early stages, the capacity of electronic stethoscopes to accurately diagnose heart sounds is impressive. Studies have shown that the mean sensitivities and specificities for diagnosing aortic regurgitation, aortic stenosis, mitral regurgitation, and mitral stenosis are 89.8 and 98.0%, 88.4 and 98.3%, 91.0 and 97.52%, and 92.2 and 99.29%, respectively [38]. The use of electronic stethoscopes to diagnose abnormal heart sounds is one example of how big data science will augment clinical providers’ cognition and support their clinical decision making.
Medical Applications of Ultrasonic Energy
Published in Dale Ensminger, Leonard J. Bond, Ultrasonics, 2011
Dale Ensminger, Leonard J. Bond
The value of the Doppler principle is not limited to blood-flow measurements or indications. It is useful in detecting and monitoring motions of internal-organ components, such as heart valves and heart muscle, where the sounds generated by these motions cannot be heard. A single unit can be synchronized to record on a multichannel recorder the sequence of heart-muscle and heart-valve movements. The Doppler signal can be separated from other sound from the different parts of an organ by filtering because these signals are pitched much lower than the carrier frequency of the ultrasonic Doppler system. Thus, it has been possible to use Doppler units for measuring mitral-valve and ventricle-wall velocities [130], providing a means of detecting mitral stenosis. Opening and closing of aortic valves also can be measured [131]. The processed Doppler signals are recorded on magnetic tape simultaneously with the frequency-modulated electrocardiogram or with measurements of intracardiac pressures.
Appropriate use criteria of left atrial appendage closure devices: latest evidences
Published in Expert Review of Medical Devices, 2023
Fabrizio Guarracini, Eleonora Bonvicini, Alberto Preda, Marta Martin, Simone Muraglia, Giulia Casagranda, Marianna Mochen, Alessio Coser, Silvia Quintarelli, Stefano Branzoli, Roberto Bonmassari, Massimiliano Marini, Patrizio Mazzone
Transthoracic echocardiography (TTE) is an imaging modality used in most patients, but it has only limited ability to study the LAA, despite an enhanced visualization is possible with ultrasound contrast [46]. TTE can be used a screening exam to evaluated absolute contraindication to the procedure, like mitral stenosis or ventricular thrombus. Transesophageal echocardiography (TEE) instead is the gold standard for LAA evaluation [47]. LAA morphology, contraction, flow velocity, and the presence of slude or thrombi should be assessed, beside near structure evaluation, like mitral valve, left atrium, and left ventriculus. The use of contrast may improve suboptimal images, while the application of 3D methodologies has improved the visualization of the LAA in its entirety with more accuracy [48].
Transcatheter edge-to-edge mitral valve repair in mitral regurgitation: current status and future prospects
Published in Expert Review of Medical Devices, 2023
Lukas Stolz, Daniel Braun, Satoshi Higuchi, Martin Orban, Philipp M. Doldi, Thomas J. Stocker, Ludwig T. Weckbach, Mirjam G. Wild, Christian Hagl, Steffen Massberg, Michael Näbauer, Jörg Hausleiter, Mathias Orban
Achieving procedural success is the most important contributor to acute and long-term clinical outcome after any intervention. Accordingly, achieving the lowest residual MR grade possibly is the aim of the M-TEER procedure, while avoiding development of mitral stenosis and SLDA (Figure 4). The literature reports that a postprocedural gradient of <5 mm Hg and a mitral valve area (MVA) of >2.0 cm2 should optimally be aimed for after M-TEER. While some studies reported a negative prognostic impact of elevated postprocedural mitral pressure gradients [51], two large retrospective observational studies could not confirm this hypothesis [52,53]. There are increasing voices that assume that the simple consideration of mean gradients is not sufficient, but that they should be considered in the context of heart rate and rhythm [54]. Beyond that the predictability of postprocedural MR might also be influenced by different device technologies, which once again outlines this topics complexity [55]. The beneficial effect of achieving mild versus moderate residual MR grade in M-TEER-treated patients with SMR has been recently shown by the COAPT and EuroSMR investigators, respectively [56,57]. In both reports, achieving mild residual MR was associated with improved survival and, in the case of the COAPT substudy, also improved quality of life.
Signal processing techniques applied to impedance cardiography ICG signals – a review
Published in Journal of Medical Engineering & Technology, 2022
Souhir Chabchoub, Sofienne Mansouri, Ridha Ben Salah
In [123], a new CAD system was developed to detect valvular heart diseases (VHDs) using the ICG signals. Six different types of ICG heartbeats were classified: normal heartbeats, mitral insufficiency heartbeats, aortic insufficiency heartbeats, mitral stenosis heartbeats, aortic stenosis heartbeats, and pulmonary stenosis heartbeats. To characterise each ICG heartbeat, temporal and time-frequency features were extracted. First, the temporal features were extracted by applying the Linear Prediction (LP) technique. Then, the time-frequency features were extracted using the Discrete Wavelet Transform (DWT) technique. Moreover, several statistical parameters (minimum, maximum, median, mean, variance, and standard deviation) were computed from the selected wavelet coefficients (the third level details D3, the fourth level details D4, and the fourth level approximation A4). In order to reduce the number of features and select the most relevant ones among them, the Student’s t-test was applied. Thereafter, the performance of the Support Vector Machine (SVM) and the K-Nearest Neighbours classifiers was investigated by applying different combinations of the selected features as inputs. Finally, the authors demonstrated that the combination between temporal features, time-frequency features and the SVM classifier achieved the highest classification performance with an overall accuracy of 98,94%.