1. What is a pacemaker? The normal human body controls the rhythm of the heart beat through the “natural pacing system”. A pacemaker delivers electrical impulses that mimic the natural pacing system of a human being, causing the heart to beat regularly. The pacemaker consists of a computer chip sealed in a box and a small, long-lasting battery. The pacemaker can be surgically implanted in the upper chest or under the skin of the abdomen, and the pulses it generates are transmitted through special wires called electrode leads, which are usually placed inside the heart. 2. Why do I need a pacemaker? If your heart rate is too slow or abnormal and you experience fainting, dizziness, fatigue, shortness of breath, palpitations, loss of consciousness, etc., you need a pacemaker to help your heart beat normally. 3. Choosing the right pacemaker Doctors choose different pacemakers for different patients. Before implanting a pacemaker, your doctor will perform exhaustive tests to determine which pacemaker is best for you. Single-chamber pacemaker: It is connected to an electrode lead in only one chamber of the heart (usually the right ventricle) and is the simplest pacemaker, but has limited function and is not a “physiological” pacing mode. Dual-chamber pacemaker: It is connected to electrode leads in both chambers of the heart, usually one in the right atrium and the other in the right ventricle. A dual-chamber pacemaker senses and delivers pulses in both chambers of the heart, which is more physiologically appropriate. The frequency of the pulses emitted by any of these pacemakers can be adjusted. Some pacemakers can provide different pacing heart rates depending on the patient’s level of activity, thus meeting the different needs of the body. The pacemaker can increase the frequency of the pulses when the patient is active and decrease the frequency of the pulses when the patient is at rest. This function is also known as “frequency response” or “frequency adaptation”.