Cellular electrophysiological

Additionally, the electrophysiological effects are often obtained from normal myocardial preparations and the abnormalities of cellular electrophysiology which cause arrhythmias in a diseased myocardium may be uniquely related to the disease process (10). Nevertheless, antiarrhythmic agent classifications have been useful as a mnemonic device. 

These detailed cell models can be used to study the development in time of processes like myocardial ischaemia (a reduction in coronary blood flow that causes under-supply of oxygen to the cardiac muscle), or effects of genetic mutations on cellular electrophysiology. They allow to predict the outcome of changes in the cell s environment, and may even be used to assess drug actions. 

While many biological molecules may be targets for oxidant stress and free radicals, it is clear that the cell membrane and its associated proteins may be particularly vulnerable. The ability of the cell to control its intracellular ionic environment as well as its ability to maintain a polarized membrane potential and electrical excitability depends on the activity of ion-translocating proteins such as channels, pumps and exchangers. Either direct or indirect disturbances of the activity of these ion translocators must ultimately underlie reperfiision and oxidant stress-induced arrhythmias in the heart. A number of studies have therefore investigated the effects of free radicals and oxidant stress on cellular electrophysiology and the activity of key membrane-bound ion translocating proteins. 

Ludvig N, Tang HM. 2000. Cellular electrophysiological changes in the hippocampus of freely behaving rats during local microdialysis with epileptogenic concentration of N-methyl-D-aspartate. Brain Res Bull 51(3) 233-240. 

One of the most important chronic alterations in the heart is the chronic phase after myocardial infarction. The postinfarction period is known to be associated with an increased risk for sudden cardiac death and for the occurrence of cardiac arrhythmia. Changes in conduction properties have been identified [Dillon et al., 1988], although the cells exhibit normal or near normal action potential characteristics [Wit and Janse, 1992]. Thus, cellular electrophysiology does not explain the complete pathophysiology of the arrhythmogenic substrate. Thus, other factors, for example structural changes and passive electrical properties, have to be taken into account. 

An extensive literature exists to point out the active role of Ca2+ in many biological processes (17) Jaffe has suggested that this might indeed be of relevance to Fucus development (8). We now show how a number of physical properties of Ca2+ strongly suggest such a role and that these factors lead the way to a number of approximations that yield a simple intuitive model for the spontaneous generation of cellular electrophysiological patterns. 

In living cells the potential dynamically changes as different ion transporters and channels controlled by various mechanisms open and close. Approaches to and examples of modeling cellular electrophysiology are covered in greater depth in Chapter 7. 

Britt, J.O., Jr., Martin, J.L., Okerberg, C.V., Dick, E.J., Jr., (2000). Histopathologic changes in the hrain, heart, and skeletal muscle of rhesus macaques, ten days after exposure to soman (an organophosphorus nerve agent). Comp. Med. 50 133-9. Carmeliet, E., Vereecke, J. (2002). Cardiac Cellular Electrophysiology. Kluwer Academic Publishers, Boston. 

Nattel S, Ranger S, and Talajic M (1990) Erythromycin-induced long QT syndrome Concordance with quinidine and underlying cellular electrophysiologic mechanism. American Journal of Medicine 89 235-238. 

Gilmour, R.F. Jr, J.J. Heger, E.N. Prystowsky D.P. Zypes. 1983. Cellular electrophysiologic abnormalities of diseased human ventricular myocardium. Am. J. Cardiol. 51 137-44. 

Britton OJ, Bueno-Orovio A, Van Ammel K, Ln HR, Towart R, Gallacher DJ, Rodriguez B (2013). Experimentally calibrated population of models predicts and explains intersnbject variability in cardiac cellular electrophysiology. Proc Natl Acad Sci USA 110 E2098-E2105. 

Baumert M, Porta A, Vos MA et al (2016) QT interval variability in body surface ECG measurement, physiological basis, and clinical value position statement and consensus guidance endorsed by the European Heart Rhythm Association jointly with the ESC Working Group on Cardiac Cellular Electrophysiology. Europace 18 925-944 Behere SP, Weindfing SN (2015) Inherited arrhythmias The cardiac channelopathies. Ann Pediatr Cardiol 8 210-220... 

Carmeliet, E., Vereecke, J., 2002. Cardiac Cellular Electrophysiology. Kluwer Academic Publishers, Boston, MA. 

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