One of the three main parts of a pacemaker is the pacemaker generator, often referred to as the pacemaker battery. The essential element of the pacemaker generator is a battery which generates an electrical signal that helps to regulate the heart's rhythm. It also consists of a computer that controls the pacemaker's function. A set of wires, called leads, are connected to the pacemaker generator at a location known as the header or connector. The leads are inserted into the heart and carry the electrical impulses created in the generator to the heart to ensure that it beats normally.
Essentially, the pacemaker generator consists of a very tiny computer and a battery to operate it. The battery is generally capable of lasting from 10 to 15 years. The computer portion of the generator is the most complex and is programmed to sense and respond to activity in the heart.
There are several possible ways in which the computer in the pacemaker generator can be programmed to sense the goings-on of the heart. The generator can be programmed to sense activity happening in the different chambers of the heart known as the atrium and ventricle. It can be programmed to sense activity from the atrium chamber, the ventricle chamber or from both of the chambers simultaneously.
Depending on how the generator is programmed, it will respond to the information received from the chambers in a variety of ways. For instance, if the generator senses that the heart is beating at a normal, healthy rhythm, then it can be programmed to remain idle and not send an electrical impulse to alter the heart rate. This prevents the pacemaker from disrupting a natural rhythm. If, however, the pacemaker generator senses a problem with the normal heart rate, such as a heart rate that is too rapid, it can be programmed to trigger and will send an electrical signal to the heart to regulate its rhythm. In many cases, the pacemaker generator can be programmed to trigger and to inhibit itself as necessary
Alternatively, the pacemaker generator can be programmed to neither inhibit nor trigger the output of an electrical signal based on what it senses. Rather, it can be programmed to send out electrical impulses at a fixed rate. In any case, it is the pacemaker generator that is capable of sensing trouble within the heart and then generating and delivering the signal through the leads that will correct the problem.