What are the Classes of Antiarrhythmic Medications?
Antiarrhythmic drugs are classified into four main classes based on their mechanism of action, which has distinct histological implications:
1. Class I: Sodium channel blockers, such as quinidine and lidocaine. These drugs slow down the conduction of electrical signals by blocking sodium channels in cardiac myocytes. 2. Class II: Beta-blockers, like propranolol and metoprolol. They reduce the effects of adrenaline on the heart, decreasing heart rate and contractility. 3. Class III: Potassium channel blockers, including amiodarone and sotalol. These drugs prolong the repolarization phase, stabilizing the cardiac rhythm. 4. Class IV: Calcium channel blockers, such as verapamil and diltiazem. They inhibit calcium influx, reducing the force of contraction and slowing down the heart rate.
