Oneliner_2113

OneLiner

Class IA antiarrhythmics, such as procainamide, are commonly used to treat aberrant conduction of electrical impulses between the atria and ventricles, and they affect both atrial and ventricular arrhythmias. They block sodium channels and thus slow conduction velocity in the atria, ventricles, and Purkinje fibers. This decreased conduction velocity slows phase 0 of the action potential (AP) and is manifested as an increased QRS duration on ECG. In addition to blocking sodium channels, class IA antiarrhythmics also block potassium channels and increase the AP duration by prolonging the effective refractory period.