Group II antiarrhythmics 

Group II antiarrhythmics: Beta-blockers. These work by blocking sympathetic nervous system stimulation to the heart, thereby reducing the transmission of impulses within the heart’s conduction system.

Class II, beta blockers: These drugs slow down the heart rate, often by blocking hormones such as adrenaline. Examples include acebutolol, atenolol, bisoprolol, metoprolol, nadolol and propranolol. Class III, potassium channel blockers: These drugs prevent potassium from getting through cell membranes.

Class II agents are anti-sympathetic nervous system agents. Most agents in this class are beta blockers. Class III agents affect potassium (K⁺) efflux. Class IV agents affect calcium channels and the AV node.

Class II antidysrhythmic medications, also known as beta blockers, are a class of medications that help control dysrhythmias, or abnormal heart rhythms. Now, there are two types of beta blockers: nonselective beta blockers, like propranolol, and cardioselective beta blockers, like metoprolol.