What is the preferred treatment for arrhythmias in damaged cardiac tissue?

The preferred treatment for arrhythmias in damaged cardiac tissue is the use of Class 1B antiarrhythmics, such as lidocaine, mexiletine, and tocainide. This class of drugs is particularly effective in situations where the myocardium is ischemic or has sustained damage, as they preferentially block sodium channels that are inactivated or inactive, which is often the case in damaged tissue.

Class 1B antiarrhythmics work by decreasing the action potential duration and refractory period in the ventricular myocardium, making them particularly suitable for ventricular arrhythmias that can arise following myocardial infarction or ischemia. Lidocaine, for instance, is commonly used in acute settings for the treatment of ventricular tachycardia and other life-threatening ventricular arrhythmias, especially after ischemic events. This mechanism helps stabilize the cardiac membrane and restore normal conduction, thereby alleviating arrhythmias.

The other classes of antiarrhythmics may not be as well-suited for damaged cardiac tissue. Beta-blockers, while useful in a broad range of arrhythmias and beneficial in reducing myocardial oxygen demand post-infarction, do not directly address the abnormal conduction associated with damaged tissue in an acute setting. Calcium channel blockers can be effective for