Class 2 antidysrhythmics work by targeting which physiological component in the body?

Class 2 antidysrhythmic medications primarily work by targeting beta-adrenergic receptors. These drugs are mainly used to decrease the heart rate and reduce myocardial oxygen demand, which is particularly beneficial in treating certain types of tachyarrhythmias. By blocking these receptors, Class 2 antidysrhythmics inhibit the effects of catecholamines (like adrenaline), leading to a decrease in heart contractility and conduction velocity, particularly through the sinoatrial and atrioventricular nodes.

The functional outcome of this action is a reduction in both automaticity and excitability in the cardiac tissue, making it less likely for abnormal rhythms to occur. This underpins their use in managing conditions such as atrial fibrillation and ventricular dysrhythmias.

While calcium channels, Purkinje fibers, and sodium channels play crucial roles in cardiac action potentials and the overall cardiac conduction system, they are the target of other classes of antidysrhythmic drugs. For instance, Class 4 agents act on calcium channels, while Class 1 agents are known for their action on sodium channels. However, the specific mechanism of Class 2 agents distinctly revolves around the modulation of beta-adrenergic receptor activity.