A pacemaker is a small device implanted in the chest to regulate the beat of the heart. Pacemakers may be used to treat a variety of heart problems, including irregularities of the heart’s rhythm (called arrhythmias) and weakness of the heart muscle.
The main part of the device is called the generator. It contains a long-lasting battery, which creates the electrical impulses that stimulate the heart.
In addition to just monitoring the heart rate and rhythm, the generators of some pacemakers also house more sophisticated monitoring and recording equipment. These sensors can keep track of the patient’s breathing rate and blood temperature and the heart’s electrical activity. This type of pacemaker can be designed to adjust the rhythm of the heart based on the patient’s activity level.
The leads are the wires that travel from the generator through a large vein in the chest to the inside of the heart. A pacemaker may have one, two, or three leads. The number of leads depends on the patient’s need.
A pacemaker is programmed to maintain a healthy heart rate. To accomplish this, the leads monitor the heart's natural heart rate and rhythm. If the heart’s rhythm drops below a certain rate, the generator will begin sending out impulses. Once the heart's natural rate returns to a healthy level, the generator stops sending out these impulses. The pacemaker keeps the heart beating with a stable, regular rhythm.