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Electrocardiogram
Published in Kayvan Najarian, Robert Splinter, Biomedical Signal and Image Processing, 2016
Kayvan Najarian, Robert Splinter
The wall of the atrium and the ventricle consists of three main layers. Moving from the inside outward, the inner lining of the heart wall is called the endocardium; it consists of a single cell layer of flat, thin endothelial cells. The second layer is the myocardium; it is the main muscle of the ventricle The epicardium is the outside lining of the ventricular wall; it consists of a single cell layer made up of flat cells. The left and right ventricles are separated by the septum, which is also a three-layer structure with endocardium, myocardium, and epicardium. The entire heart is suspended in the pericardial sack, which provides free movement in the area of the chest in between the lungs on the left side of the body.
Heart regeneration
Published in David M. Gardiner, Regenerative Engineering and Developmental Biology, 2017
The cellular engines that run the pump (the heart) are the cardiac muscle cells, the cardiomyocytes. These contractive cells are connected in a functional syncytium via intercalated discs made up of three different types of cell junctions: the fascia adherens, the anchor points for actin filaments, aiding in the transmission of contractile forces; the macula adherens (desmosomes), adhesion sites between cardiomyocytes; and gap junctions that allow action potentials initially generated in the pacemaker region of the sinoatrial node and traveling through the cardiac conduction system to spread between cardiomyocytes, causing depolarization and contraction of the heart in a controlled fashion. The inner surface of the myocardium is lined with endocardium, an epithelial layer of similar origin as the endothelium lining the inside of blood vessels. The endocardium provides a smooth and non-adherent surface for blood to pass by and provides a controlled barrier between the blood’s extracellular fluid and the extracellular fluid that bathes the cardiomyocytes. The outer surface of the myocardium is lined by another epithelium, the epicardium, which is composed of connective tissue and protectively encompasses the heart. Both these epithelial layers play important roles during cardiac development and in the regulation of cardiac regeneration in species capable of such a feat (for detailed review, see Kikuchi and Poss 2012* ). However, cardiomyocytes are the primary cells in the functioning heart and are what make the clock tick, so to speak. From an engineering perspective, the focus must first be on developing technologies to generate cardiomyocytes. This poses the question: from where do we get new cardiomyocytes in the case of major myocardial loss after an ischemic event?
Optimised ensemble learning-based IoT-enabled heart disease monitoring system: an optimal fuzzy ranking concept
Published in Computer Methods in Biomechanics and Biomedical Engineering: Imaging & Visualization, 2023
N.V.L.M Krishna Munagala, Lakshmi Rajeswara Rao Langoju, A. Daisy Rani, D.V.rama Koti Reddy
In recent days, heart diseases are increased among people around the world, hence which have attained a huge interest in the clinical field among different life-threatening diseases (Lim et al. 2009). Heart disease is further promoted into one of the most widespread diseases worldwide owing to the current lifestyle (Rogers et al. 2019). The heart is one of the essential organs that deliver nutrients and oxygen to entire organs for metabolism by circulating the blood throughout the human body. Blood circulation is carried out by the contraction of cardiac muscle that helps in maintaining the ‘body temperature at approximately 37°C’ (Meng et al. 2020). Body temperature is affected while observing abnormal cardiac functions. As the human body ages, the cardiac function is degenerated, thus resulting in cardiovascular diseases. As the primary part of the human is the heart, it consists of various components like the right ventricle, left ventricle, right and left atrium, epicardium, cardiac muscle and endocardium (Gong et al. 2020). The flow of blood circulation is determined through the valvular, digitalisation and contraction closure of the heart. In the initial stages, various clinical symptoms are observed, and serious damage is noticed when the disease worsens, which leads to severe damage to the physical health of persons (Li et al. 2020a). However, in most cases, heart disease patients do not experience sickness till reaching the last stage.
Interference of cardiovascular implantable electronic devices by static electric and magnetic fields
Published in Expert Review of Medical Devices, 2021
Kai Jagielski, Thomas Kraus, Dominik Stunder
A bipolar PM system was not constructed like the unipolar system because the structures of a bipolar probe are below the resolution of the body model of 0.5 mm and would exceed the RAM limits in a simulation. Alternative approaches, such as in reference [22], are not reasonable for this study. In [22], the bipolar PM system was constructed with two conductors parallel to each other. The authors avoid a difference in the effective area of the two conductors by arranging the conductors one behind the other in the direction of the alternating magnetic field source. This approach would not be reasonable in this study because of the rotational motion so that a difference in the effective area would not be avoidable. Instead, the induced voltage was measured directly between the electrodes (tip to ring) with a 10 mm distance at different lead tip positions in the heart chamber. This approach is in good agreement with in vivo results and shows that the measured voltage at a line path in the heart depends on its orientation [23]. Therefore, the voltages along several line paths are computed: 49 directions (33 on the x/y/z-planes and 16 in between) each in the blood of the atrial and the ventricular chamber and 77 orientations with proper implantation angles at four implantation sites at the endocardium (Figure 2(b)). The lead tips at the endocardium extend only to 20–30% into the heart muscle but remain mostly in the heart lumen.
Computational modelling of mechano-electric feedback and its arrhythmogenic effects in human ventricular models
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
Yongjae Lee, Barış Cansız, Michael Kaliske
This section investigates the effect of MEF on normal heart cycles and arrhythmogenesis by using the introduced finite element framework. The heart geometries, transmurally changing fibre direction, and boundary conditions are depicted in Figure 3. The fibre angle in both heart models is linearly interpolated from 70 on the endocardium to on the epicardium. The biventricular heart model is constrained by attaching linear springs to the nodes at the basal and epicardial surface with different stiffness values. For the left ventricular (LV) heart model, the linear springs are attached to the nodes at the basal, mid-epicardial and apical surface with different stiffness values.