Pacemakers are electronic therapeutic devices implanted in the body, which are designed to treat cardiac dysfunction caused by certain arrhythmias by distributing electrical pulses powered by batteries through pulse generators and stimulating the heart muscle contacted by the electrodes through the conduction of wires, thus causing the heart to excite and contract. Since the first pacemaker was implanted in the human body in 1958, pacemaker manufacturing technology and techniques have developed rapidly and their functions have become increasingly sophisticated. While the application of pacemakers has successfully treated slow arrhythmias and saved the lives of thousands of patients, pacemakers have also begun to be applied to tachyarrhythmias and non-cardiac diseases, such as the prevention of paroxysmal atrial tachyarrhythmias, carotid sinus syncope, and biventricular synchronization for drug-refractory congestive heart failure. Artificial cardiac pacing systems consist of two main components: the pulse generator and the electrode leads. The pulse generator is often referred to as the pacemaker alone. In addition to the above-mentioned pacing function, the pacing system also has the function of sensing the heart’s own electrical activity back to the pulse generator. The pacemaker consists mainly of a power source (i.e., a battery, nowadays mainly lithium-iodine batteries) and an electronic process that generates and outputs electrical pulses. The electrode lead is a conductive metal wire with an outer insulating layer wrapped around it, whose function is to transmit the electrical impulses from the pacemaker to the heart and to transmit the intracavitary ECG of the heart to the pacemaker’s perception line. There are two types of artificial cardiac pacing: temporary and permanent, which have different indications. Temporary pacing is a temporary or transient artificial pacing procedure that does not involve the permanent implantation of a pacing electrode lead. The pacing leads are placed outside the body for a period of less than 2 weeks and are withdrawn after the diagnostic, therapeutic and preventive purposes have been achieved. If continued pacing is required, a permanent pacemaker should be considered. Any patient with symptomatic or hemodynamically altered bradycardia is a candidate for temporary pacing. The purpose of temporary pacing is usually divided into therapeutic, diagnostic and preventive. 1. Therapeutic aspects (1) A-S syndrome episodes: cardiac arrest with A-S syndrome episodes due to atrioventricular block and sinus node failure caused by various causes (acute myocardial infarction, acute myocarditis, poisoning due to digitalis or antiarrhythmic drugs, electrolyte disturbances, etc.) are absolute indications for emergency temporary cardiac pacing. (2) Transition of patients with unstable heart rhythms prior to placement of a permanent pacemaker. (3) Third-degree atrioventricular block caused by direct cardiac surgery. (4) Apical torsional and/or sustained ventricular tachycardia induced by bradycardia that has failed to respond to drug therapy. 2. Diagnostic aspects As an adjunct to certain clinical diagnoses and electrophysiological examinations. For example, to determine: (1) sinus node function; (2) atrioventricular node function; (3) type of pre-excitation syndrome; (4) foldback arrhythmia; (5) effect of antiarrhythmic drugs. 3. Prevention (1) Patients at high risk for significant bradycardia, such as certain slow arrhythmias in acute myocardial infarction, patients with cardiac conduction system insufficiency who are scheduled for major surgery or cardiac interventional procedures, patients with suspected sinus node dysfunction undergoing cardioversion therapy for rapid arrhythmias, and patients with pre-existing left bundle branch block undergoing right heart catheterization. (2) Transition to a new pacemaker in pacemaker-dependent patients. The indications for permanent cardiac pacing have gradually expanded with the improvement of pacing engineering. In the early years, the main purpose of pacemaker implantation was to save the patient’s life, but now it also includes restoring the patient’s work capacity and quality of life. In 2012, the American College of Cardiology/American Heart Association/American Heart Rhythm Association reformulated guidelines for pacemaker implantation. The rational selection of a pacemaker for a specific patient is an issue that clinicians often have to face. The principles are as follows: 1. Choose VVI(R) if chronic persistent atrial fibrillation is present or if atrial stasis is present. 2. Choose AAI(R) if there is no AV block or if the predicted probability of near-term AV block is low in those with sinus node insufficiency; otherwise, choose DDD(R). 3. For those with AV block, choose VVI(R) if (i) persistent atrial tachyarrhythmia is present; (ii) sick sinus syndrome is present, choose DDD(R); (iii) normal sinus node function or low probability of expected sinus node insufficiency, choose VDD or DDD. Single ventricular pacing is no longer recommended, and dual-chamber pacing has increased survival-corrected quality of life at a price that is generally considered acceptable. Quality of life. The choice between AAI or DDD pacing, although DDD is more expensive, should be considered in the context of the patient’s potential for developing AV block. In addition, the patient’s age, cardiac disease and co-morbidities, financial status and overall general condition of the patient should be taken into account. There are five methods of temporary cardiac pacing: percutaneous pacing, transesophageal pacing, transthoracic puncture pacing, open epicardial pacing, and transvenous pacing. At present, the latter is mostly chosen. Temporary pacing leads are usually delivered by puncture through the femoral, subclavian, or internal jugular vein. Displacement of the electrode leads is more common than with permanent pacing. Postoperative ECG monitoring should be intensified, including early increases in pacing threshold, changes in sensory sensitivity, and electrode lead dislocation, especially in pacemaker-dependent patients. In addition, since the electrode lead is connected to the outside world through the puncture point, care should be taken to avoid local cleanliness and infection, especially in those who have been placed for a long time. In addition, after temporary pacing via the femoral vein, the patient should be kept in a lying position with the lower extremity on the side of the venous puncture restrained. The majority of permanent cardiac pacing currently uses endocardial electrode leads. Technical points include vein selection, electrode fixation of the lead and pacemaker placement. 1. Vein selection. Usually, the veins that can be inserted with electrode leads are: superficial veins are cephalic veins and external jugular veins, deep veins are subclavian veins and axillary veins, and internal jugular veins. Usually the cephalic vein or subclavian vein on the opposite side of the customary hand is preferred, and then the internal or external jugular vein is selected if it is unsuccessful. 2.Placement of electrode leads. The electrode leads are placed in the heart chambers to be paced according to the need, usually with passive fixation, or with active fixation of the electrode leads. 3. Placement of the pacemaker. The pacemaker is usually buried under the skin of the chest on the same side of the electrode lead. The electrode lead is connected to the pulse generator, and the excess lead is placed in the subcutaneous pocket near the muscle surface and the pacemaker near the skin. In brief, the method is to insert the electrode lead through a vein in the arm or below the clavicle, under X-ray fluoroscopy, into the intended cardiac pacing position, secure it and test it. A pacemaker connected to the electrode lead is then buried in the chest, the skin is sutured, and the procedure is completed. Unlike other cardiac interventions, the successful implantation of a pacemaker is only a relatively simple first step, but the big but important task is the long-term follow-up of the patient after the procedure. The follow-up begins on the day of implantation and continues throughout the patient’s life. After the operation, the patient is taught to take his or her own pulse, as checking the pulse is an easy and effective way to monitor the work of the pacemaker. Make sure that you are in the same physical state every day when you monitor your pulse, such as when you wake up in the morning or after 15 m of meditation. In the early stages of pacemaker placement, the pacing threshold is often unstable and needs to be adjusted in time. Therefore, regular check-ups are required, usually every 2 weeks for 1 month and once a month for 3 months (depending on the patient). In addition to the electrode position, sleep deprivation, full meals, antiarrhythmic drugs, and high blood pressure may have an effect on the threshold. Therefore, postoperative patients should maintain a good mood, ensure a regular life and resting system, and avoid all possible adverse factors. The follow-up period and content of the follow-up should be tight at both ends and loose in the middle. Pacemaker safety Many patients are concerned about the installation of pacemakers, but in fact, pacemaker installation is very safe. In patients who meet the indications for pacemaker implantation, the benefits far outweigh the disadvantages if they are treated regularly and followed up regularly.