Phenylalkylamines and benzothiazepines exert cardiac actions in vivo and are effective antiarrhythmic drugs, whereas dihydropyridines lack antiarrhythmic activity due to high vascular selectivity.
The review highlights the ongoing relevance and mechanisms of class IV antiarrhythmic agents, including established and novel calcium channel antagonists, in managing cardiac arrhythmias.
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.
Szentandrássy et al. (Tue,) conducted a review in Cardiac arrhythmias. Calcium channel antagonists (Class IV antiarrhythmic agents) was evaluated. Phenylalkylamines and benzothiazepines exert cardiac actions in vivo and are effective antiarrhythmic drugs, whereas dihydropyridines lack antiarrhythmic activity due to high vascular selectivity.