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Electrical stimulation of cells derived from muscle
Published in Ze Zhang, Mahmoud Rouabhia, Simon E. Moulton, Conductive Polymers, 2018
Anita F. Quigley, Justin L. Bourke, Robert M. I. Kapsa
There has been some investigation into the mechanisms by which this effect is mediated at the macroscopic level. Electrical stimulation has been shown to influence myofiber distribution and type (Windisch et al. 1998; Bergh et al. 2010), as well improve or increase the capillary density and blood flow in muscle tissues (Hudlicka et al. 1994; Mathieu-Costello et al. 1996). These changes are reminiscent of changes seen with exercise training and electrical stimulation has been shown to elicit positive effects in critically ill patients (Karatzanos et al. 2012; Routsi et al. 2010; Vivodtzev et al. 2012; Banerjee 2010). These changes at the macroscopic level point to cellular and molecular responses that underlie muscle adaption to increased “exercise loading” mediated by electrical stimulation. In the case of muscle atrophy, it is thought that use of the muscle, through artificial means, prevents changes associated with disuse. The cardiac pacemaker, one of the best-known bionic devices, was developed to provide electrical stimulation directly to the cardiac muscle in order to maintain appropriate function. Pacemaker cells are responsible for coordinating cardiac contraction; however, in a number of patients with conduction defects (and other cardiac defects), this role needs to be fulfilled artificially. The pacemaker uses electrical stimulation to promote timed contraction of cardiac muscle, regulating the beating of the heart. In contrast to the use of EMS in skeletal muscle, the pacemaker is used to regulate normal function rather than to provide a therapeutic function.
Principles of Electrocardiography
Published in Joseph D. Bronzino, Donald R. Peterson, Biomedical Engineering Fundamentals, 2019
e evolution of the ambulatory or Holter ECG has an interesting history and its evolution closely followed both technical and clinical progress. e original, analog tape-based, portable ECG resembled a fully loaded backpack and was developed by Dr. Holter in the early 1960s [17], but was soon followed by more compact devices that could be worn on the belt. e original large-scale clinical use of this technology was to identify patients who developed heart block transiently and could be treated by implanting a cardiac pacemaker. is required the secondary development of a device which could rapidly play back the 24 h of tape-recorded ECG signals and present to the technician or physician a means of identifying periods of time where the patient’s heart rate became abnormally low. e scanners had the circuitry to not only playback the ECG at speeds 30-60 times real time, but to detect the beats and display them in a superimposed mode on a cathode ray tube (CRT) screen. In addition, an audible tachometer could be used to identify the periods of low heart rate. With this playback capability came numerous other observations such as the identication of premature ventricular beats (PVBs), which led to the development of techniques to identify and quantify their number. Together with the development of antiarrhythmic drugs a coupling was formed between pharmaceutical therapy and the diagnostic tool for quantifying PVBs. ECG tapes were recorded before and aer drug administration and the drug ecacy was measured by the reduction of the number of PVBs. e scanner technology for detecting and quantifying these arrhythmias was originally implemented with analog hardware but soon advanced to computer
Electrical safety
Published in Phil Hughes, Ed Ferrett, Introduction to Health and Safety in Construction, 2015
Strong electromagnetic fields induce surface charges on people. If these charges accumulate, skin sensation is affected and spark discharges to earth may cause localised pain or bruising. Whether prolonged exposure to strong fields has any other significant effects on health has not been proved. However, the action of an implanted cardiac pacemaker may be disturbed by the close proximity of its wearer to a powerful electromagnetic field. The health effects of arcing and other non-ionising radiation are covered in Chapter 15.
Semi-quantitative methodology to assess health and safety risks arising from exposure to electromagnetic fields up to 300 GHz in workplaces according to Italian regulations
Published in International Journal of Occupational Safety and Ergonomics, 2023
For wearers of AIMDs, the technical Standard No. 50527-1:2016 [50] establishes that the assessment of compliance with the RLs of Council Recommendation 1999/519/EC [31] should be carried out without including any time average for frequencies above 100 kHz, for the purpose of preventing possible indirect effects of EMF interference with the normal operation of the devices. In relation to exposure to static magnetic fields, most cardiac pacemakers are unlikely to be disturbed in fields below the AL of 0.5 mT referred to in Directive 2013/35/EU [32]. Therefore, workers bearing AIMDs must not enter places where the magnetic flux density for static magnetic fields is greater than 0.5 mT. The same considerations apply to medical devices worn on the body that should be assimilated to AIMDs for the purpose of EMF risk assessment [34,44].