Drugs that slow down the heart rate are seen in the following categories: 1. Sodium channel blockers, quinidine, lidocaine, and propafenone are all sodium channel blockers. In general, these drugs are mainly for rapid arrhythmias, such as paroxysmal supraventricular tachycardia, frequent atrial premature beats and ventricular premature beats. 2. beta-blockers, mainly betaxolol, bisoprolol and propranolol, which are mainly used for sinus tachycardia, frequent atrial premature beats and ventricular premature beats, and also for heart rate control in patients with atrial fibrillation. 3. potassium channel Blockers, which can prolong repolarization, are mainly amiodarone. Amiodarone is widely used in atrial fibrillation and other rapid arrhythmias. 4, calcium channel blockers, the main representative drug is verapamil.