Cardiac arrhythmias types

Antiarrhythmic dragp are used to treat various types of cardiac arrhythmias. There are initial preadministration assessments the nurse performs before starting therapy that are the same for all antiarrhythmic drags. These assessments include ... 

Splawski, 1., Timothy, KW., Decher, N., Kumar, P., Sachse, F.B., Beggs, A.H., Sanguinetti, M.C. and Keating, M.T (2005) Severe arrhythmia disorder caused by cardiac L-type calcium channel mutations. Proceedings of the National Academy of Sciences of the United States of America, 102, 8089-8096. 

The side-effects of cardiac glycosides are mostly caused by electrophysiological/neuronal phenomena. Gastro-intestinal adverse reactions are probably triggered by effects on the central nervous system. Various types of cardiac arrhythmias are caused by the influence of the drugs on nodal tissues in the heart. The risk of arrhythmia is strongly enhanced by low plasma potassium concentrations. 

Splawski I, et al Severe arrhythmia disorder caused by cardiac L-type calcium channel mutations. Proc Natl Acad Sci USA 2005 102 8089. [PMID 15863612]... 

Beta antagonists are generally administered for their effect on the beta-1 receptors that are located on the heart.31 When stimulated, these receptors mediate an increase in cardiac contractility and rate of contraction. By blocking these receptors, beta antagonists reduce the rate and force of myocardial contractions. Consequently, beta antagonists are frequently used to decrease cardiac workload in conditions such as hypertension and certain types of angina pectoris. Beta blockers may also be used to normalize heart rate in certain forms of cardiac arrhythmias. Specific clinical applications of individual beta blockers are summarized in Table 20-2. 

Further variants on the terpenoid indole alkaloid skeleton (Figure 6.82) are found in ibogaine from Tabemanthe iboga, vincamine from Vinca minor, and ajmaline from Rauwolfia serpentina. Ibogaine is simply a C9 Iboga type alkaloid, but is of interest as an experimental drug to treat heroin addiction. In a number of European countries, vincamine is used clinically as a vasodilator to increase cerebral blood flow in cases of senility, and ajmaline for cardiac arrhythmias. Ajmaline... 

Spafford JD, Munno DW, Van Nierop P, Feng ZP, Jarvis SE, Gallin WJ, Smit AB, Zamponi GW, Syed NI (2003) Calcium channel structural determinants of synaptic transmission between identified invertebrate neurons. J Biol Chem 278 4258-67 Spafford JD, Zamponi GW (2003) Functional interactions between presynaptic calcium channels and the neurotransmitter release machinery. Curr Opin Neurobiol 13 308-14 Splawski I, Timothy KW, Decher N, Kumar P, Sachse FB, Beggs AH, Sanguinetti MC, Keating MT (2005) Severe arrhythmia disorder caused by cardiac L-type calcium channel mutations. Proc Natl Acad Sci U S A 102 8089-96 discussion 8086-8... 

Since the persistent depolarization of end plates is associated with an ef ux of K+ ions, hyperkalemia can result (risk of cardiac arrhythmias). Only in a few muscle types (e. g., extraocular muscle) are muscle fibers supplied with multiple end plates and therefore capable of a graded response. Here succinylcholine causes depolarization distributed over the entire fiber, which responds with a contracture. Intraocular pressure rises, which must be taken into account during eye surgery. 

Purine receptors Adenosine, AMP, ADP and ATP can act extracellularly as hormones or transmitters, too In particular, adenosine receptors that occur in the heart, the brain, and the lung are the targets of theophylline and caffeine. Adenosine itself is being used for the treatment of a special type of cardiac arrhythmia. 

Impaired liver function, whether due to primary cellular insufficiency or to low liver blood flow as in cardiac failure, may both delay elimination and allow higher peak plasma concentrations of both types of local anaesthetic. This is likely to be important only with large or repeated doses or infusions. These considerations are important in the management of cardiac arrhythmias by i.v. infusion of lignocaine (lidocaine) (see p. 502). 

Cardiac arrhythmias result from reperfusion of ischaemic tissue. These vary in type and are often transient, a factor which may influence the decision whether or not to treat. 

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