CLINICAL REVIEW ARTICLES IN PHYSIO PHARMACOLOGY VOLUME III

Book excerpt: Antiarrhythmic drugs play a key role regarding abnormal heart rhythms. Anti-arrhythmic drugs are divided into different classes dependent on their primary mechanism of action. These drugs are regarded as into four main categories such as class I (sodium channel blockers), class II(beta _ blockers), class III (potassium channel blockers) and class IV (calcium channel blockers). Class I anti arrhythmics specifically act on sodium channels, which play a role in the initiation and conduction of action potentials particularly in Cardiac cells. Class II anti arrhythmics act by decreasing the effects of adrenaline on the heart. Class III antiarrhythmics affect potassium channels and carry on the repolarization phase of the Cardiac action potential. Potential class IV antiarthmics stop calcium influx during depolarization and result in acdecrement in the heart rate and the forcec of contraction. Finally it is concluded that anti arrhythmic drugs play a critical role in managing various vtyoes of arrhythmias.