This document discusses anti-arrhythmic drugs and their use in treating abnormal heart rhythms (arrhythmias). It begins by explaining the normal physiology of the cardiac action potential and electrocardiogram. Arrhythmias are then classified and the mechanisms discussed. Anti-arrhythmic drugs are classified according to their effects on the action potential and important drugs from each class are described, including their mechanisms of action, uses, dosing, and side effects. Non-pharmacological treatments are also summarized. Overall, the document provides a comprehensive overview of arrhythmia treatment and management.