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Biological Responses in Context
Published in Arthur T. Johnson, Biology for Engineers, 2019
Hypertension is usually a temporary adjustment to emotional stress or trauma, but after sustained hypertension, the condition perpetuates itself, becoming essential hypertension. The left ventricle of the heart, challenged by the need to pump blood against pressure higher than normal, develops a thickened muscular wall, called cardiac hypertrophy. The extra muscular mass requires additional oxygen, and any decrease in coronary blood flow has more serious consequences in hypertensive patients than in normal individuals. Myocardial infarction (muscle cells die due to lack of oxygen) is therefore more of a threat in hypertensive patients than in normal ones. Even with the implantation of a replacement heart, the underlying causes of the heart failure have not been eliminated, and the cycle is likely to repeat.
Safe Handling of Vacuum Tube Devices
Published in Jerry C. Whitaker, Power Vacuum Tubes, 2017
Table 13.1 lists some effects that typically result when a person is connected across a current source with a hand-to-hand resistance of 2.4 kΩ. The table shows that a current of approximately 50 mA will flow between the hands, if one hand is in contact with a 120 V ac source and the other hand is grounded. The table indicates that even the relatively small current of 50 mA can produce ventricular fibrillation of the heart, and perhaps death. Medical literature describes ventricular fibrillation as rapid, uncoordinated contractions of the ventricles of the heart, resulting in loss of synchronization between heartbeat and pulse beat. The electrocardiograms shown in Figure 13.1 compare a healthy heart rhythm with one in ventricular fibrillation. Unfortunately, once ventricular fibrillation occurs, it will continue. Barring resuscitation techniques, death will ensue within a few minutes.
Human physiology, hazards and health risks
Published in Stephen Battersby, Clay's Handbook of Environmental Health, 2016
David J. Baker, Naima Bradley, Alec Dobney, Virginia Murray, Jill R. Meara, John O’Hagan, Neil P. McColl, Caryn L. Cox
The heart consists of two pumps, right and left, which circulate blood round the body. Each pump has two chambers, the atrium which collects the blood either from the lungs (the left atrium) or from the tissues (right atrium) and then passes through valves to the major pumping chambers, the ventricles. Thus the left ventricle pumps the blood with oxygen whilst the right ventricle pumps the blood that has returned from the cells or tissues (after extraction of oxygen and nutrients and containing greater amounts of carbon dioxide than in the blood which reached the cells from the left ventricle) to the lungs to get rid of carbon dioxide and pick up more oxygen.
Cardiac implantable electronic devices and cybersecurity
Published in Expert Review of Medical Devices, 2021
Bhakti Patel, Amgad N. Makaryus
The implantable loop recorder is a device that is inserted into the patient’s subcutaneous tissue. It functions to diagnose heart rhythm disorders by monitoring the heart rhythm and has the ability to record and store ECGs when a patient is in bradycardia or tachycardia [6]. The remote monitoring feature with the implantable loop recorder provides great benefits, such as decreasing the time it takes to diagnose a patient’s condition as well as the follow-up treatment plan [6]. In a study by Drak-Hernandez et al., the mean time from implant to diagnosis was compared in patients with remote monitoring to those with conventional follow-up appointments following an implantable loop recorder. The results showed that patients with the remote monitoring feature had significantly shorter time to diagnosis and targeted treatment [7]. Additionally, remote monitoring with implantable loop recorders not only enables more timely diagnosis, but also allows data to be transferred in order to prevent memory overflow. This decreases the risk for information loss as a result of memory overflow as well as decreased outpatient visits to record/upload data [7]. For patients with heart failure, the implanted left-ventricular assist device (LVAD) helps the left-ventricle pump blood to the body. Remote monitoring of the LVAD increases the early detection of problems and their treatment [8]. Overall, remote monitoring serves as an advantage for many cardiac devices as it allows for efficient and quick data transfer to the physician as well as early diagnosis of a heart condition.
Circulatory System Based Optimization (CSBO): an expert multilevel biologically inspired meta-heuristic algorithm
Published in Engineering Applications of Computational Fluid Mechanics, 2022
Mojtaba Ghasemi, Mohammad-Amin Akbari, Changhyun Jun, Sayed M. Bateni, Mohsen Zare, Amir Zahedi, Hao-Ting Pai, Shahab S. Band, Massoud Moslehpour, Kwok-Wing Chau
According to the simple inspiration model from the circulatory system of the body’s regular performance in Figure 1, the body’s blood vessels are functionally divided into two distinctive circuits: the pulmonary circuit and the systemic circuit. The pump for the pulmonary circuit, which circulates blood through the lungs, is the right ventricle. The left ventricle is the pump for the systemic circuit, which provides the blood supply for the body’s tissue cells. Pulmonary circulation transports oxygen-poor blood from the right ventricle to the lungs, where the blood picks up a new blood supply. Then it returns the oxygen-rich blood to the left atrium.
A hybrid algorithm for heart sounds segmentation based on phonocardiogram
Published in Journal of Medical Engineering & Technology, 2019
The human heart is one of the most critical organs in the body, which sends blood to various parts through its pumping like mechanism. A set of mechanical and electrical activities is performed to ensure that the human heart carries out its blood transfusion function correctly. The heart is divided into four chambers. The two upper called the atria, and the two lower are ventricles. The ventricles have thicker walls and pump blood to the lungs and body. Unfortunately, today the mortality rate due to heart disease, including heart valve defects is very high. Therefore, the diagnosis and prevention of heart failure are crucial.