Antiarrhythmic medicines
This information is not intended for purposes of treatment without physician.
Description of the pharmacological group
Antiarrhythmic medicines
Antiarrhythmic preparations are medicines, which have the normalizing effect on the disrupted rhythm of the heart contractions. They relate to the different classes of chemical compounds and belong to different pharmacological groups (sedative, tranquilizers, cholinergic antagonists and cholinomimetics, adrenoblockers and adrenomimetics, local anesthetics, some antiepileptic means, preparations, which contain potassium salts, the antagonists of the of calcium ions and others).
It is at present proven that the mechanism of the action of antiarrhythmic medicines is connected with their ability to one degree or another restore the normal electrophysiological processes, which take place in the heart muscle, since by the precisely electrophysiological properties of cardiomyocytes (cells of heart) is caused their capability for synchronous, rhythmical reductions. These properties of cardiomyocytes are the basis of the characteristic functions of heart muscle - automatism, excitability and conductivity, which in turn prepare heart to its resulting function - reduction, i.e., to the realization of the continuous motion of the blood in the vascular channel.
At the same time there is a number of the preparations, basic pharmacological property of which is the normalizing influence on the rhythm of the heart in the various forms of arrhythmias. These means, and also number Beta-adrenergic blockers, the antagonists of calcium ions, Lidocaine and other local anesthetics, anticonvulsive preparation diphenine in connection with their expressed antiarrhythmic activity unite into the group of antiarrhythmic preparations.
Classification of the antiarrhythmic medicines
At present in the clinical practice is used the sufficiently large number of antiarrhythmic medicines, which possess different mechanisms, which lie at the basis of their antiarrhythmic action. However, majority antiarrhythmic of medicines to one degree or another affect the form of the action potential of cardiomyocytes, i.e. realize their effects, influencing these or other transmembrane ion currents. According to the ability of antiarrhythmic medicines to influence the form of action potential their they subdivide into four classes. It proposed for the first time similar classification in 1969. Dutch physiologist E.M.Vaughan Williams (E.M. Vaughan Williamse). Somewhat later, in 1971 ; E.M.Vaughan Williamse together with B. Singh modified its classification. However, this classification did not completely reflect the special feature of the mechanism of action antiarrhythmic of medicines of the I class; therefore in 1979.D.Harrison proposed to subdivide this group of preparations into three sub-classes - A, B and C.
According to this classification antiarrhythmic medicines are subdivided into the following four classes:
I class - blockers of sodium channels;
IA class - medicines, which moderately retard conducting and which lengthen action potential, moracizine, procainamide, quinidine and other;
IB class - medicines, which minimally retard conducting and insignificantly which shorten action potential, lidocaine, mexiletin, pyromecaine and other;
IC class - medicines, which considerably retard conducting and minimally which lengthen action potential, lappaconitine hydrobromide hydrobromide, propafenone, flecainide, ethacyzin and other
II class - β- adrenoblockers - ateenolol, acebutolol, propranolol (inderal) and other;
III class - medicines, which lengthen the period of repolarization, Cordarone (amiodarone), bretiliya tosylate, ibutilide, sotalol and other;
IV class - the blockers of calcium channels - Verapamil, Diltiazem (sin. Cardizem) and other
Antiarrhythmics are used for treatment of paroxysmal tachycardia, paroxysm of atrial fibrillation