Pacemakers are cardiac implantable electronic devices that help the human heart to move. Pacemakers currently in clinical use include single-chamber atrial pacemakers, dual-chamber atrioventricular synchronous pacemakers, etc. The choice of pacemaker depends on the type of disease, symptoms, severity, age of the patient, economic conditions, etc. If the patient has a pathological sinus node syndrome without AV block, a single-chamber atrial pacemaker or a dual-chamber AV pacemaker is selected. If the patient has atrioventricular block with an excessively slow heart rate and frequent syncope, ischemia, and hypotension, a dual-chamber pacemaker should be considered; if the patient has frequent syncope due to vasovagal syncope, a dual-chamber pacemaker that responds to the heartbeat should be selected; if the patient has heart failure with slow arrhythmias, a three- or four-chamber pacemaker should be selected. In addition, implantable cardioverter defibrillators can be used to treat patients with slow arrhythmias combined with ventricular tachycardia and ventricular fibrillation.