The heart is a muscular, fist-sized pump with four chambers: two upper chambers (atria) and two lower chambers (ventricles). This intricate organ relies on an internal electrical system to beat at a consistent and appropriate rate. In a resting adult, the heart typically beats 60 to 80 times per minute. This electrical system originates from a specialized group of cells in the upper part of the heart, known as the sinus node, and propagates electrical impulses throughout the heart. These impulses coordinate the contraction of the heart muscle, enabling it to pump blood efficiently throughout the body.

Various factors, including aging, heart muscle damage from a heart attack, certain medications, and genetic conditions, can disrupt the heart's electrical system, leading to irregular or abnormally slow heart rhythms (bradycardia). When the heart's natural electrical control system malfunctions, a pacemaker may be necessary. A pacemaker is a small, battery-powered medical device designed to monitor the heart's rhythm. If it detects an irregular or excessively slow heartbeat, it delivers electrical impulses to the heart to help it maintain a normal rate. A pacemaker typically consists of two main components: a generator and leads. The generator houses the battery and the electronic circuitry that controls the heart's pacing. The leads are thin, insulated wires that connect the generator to the heart, transmitting these electrical messages. Pacemaker types vary depending on the patient's specific condition and include single-chamber, dual-chamber, and biventricular pacemakers.