Title:Class IV Antiarrhythmic Agents: New Compounds Using an Old Strategy
Volume: 21
Issue: 8
Author(s): Norbert Szentandrassy, Denes Nagy, Bence Hegyi, Janos Magyar, Tamas Banyasz and Peter P. Nanasi
Affiliation:
Keywords:
Action potential, antiarrhythmic drugs, benzothiazepine, calcium channel, calcium channel antagonist, cardiac arrhythmia, cardiac
ion currents, phenylalkylamine.
Abstract: Cardiac arrhythmias are a major cause of morbidity and mortality in the industrialized world. Among their treatment regimens
one can find the calcium channel antagonists (CCAs), the class IV agents. In the cardiovascular system L- and T-type calcium channels
are found on vascular smooth muscle cells and cardiac myocytes with well defined physiological roles. Inhibition of calcium channels by
CCAs has widely been used in clinical practice for several decades. Cardiovascular disorders are one of the many fields of medicine in
which CCAs are used for various reasons and conditions. The three main indications of them are hypertension, angina and various cardiac
arrhythmias. The most important classes of CCAs are dihydropyridines, phenylalkylamines and benzothiazepines but some newer
compounds do not fall into any of these major classes. Dihydropyridines are not used in the antiarrhythmic therapy but are good vasodilators
and antianginal agents. In contrast, phenylalkylamines and benzothiazepines exert cardiac actions in vivo and therefore these are one
choice of antiarrhythmic drugs. This review focuses on phenylalkylamines, benzothiazepines and on new drugs with potential antiarrhythmic
action in the heart as well as the mechanisms how calcium channels antagonism can lead to an antiarrhythmic action.
