What is a Pacemaker?

Pacemakers are implantable devices used to treat symptomatic bradycardias not caused by a treatable condition or medication. A Pacemaker system consists of a pulse generator (which is typically referred to as "the pacemaker") and one or two insulation-coated pacing leads or wires. One end of the pacing lead(s) plugs into the connector block of the pulse generator, while the other end, termed the pacing/sensing electrodes, are positioned inside the heart and make contact with the heart tissue. Bipolar sensing and pacing is preferred, meaning that two closely-spaced electrodes are incorporated into the wire. A pacing wire, with its associated bipolar electrodes, can be positioned in the right atrium (for atrial sensing and pacing), as well as the right ventricle (for ventricular sensing and pacing). Pulses of electrical current flow from the pulse generator (powered by a battery) to the pacing electrodes, and then into the heart tissue. The electrical pulse stimulates global electrical activation of the heart causing a contraction of the heart muscle and pumping of blood.

A pacemaker system consists of a pulse generator and leads. There are two general types of leads: those that attach to cardiac tissue by an active fixation mechanism (a small "corkscrew" device at the tip) and those that attach by a passive mechanism involving small "hooks" or tines at the lead tip.

Because modern pacemakers have sensing capabilities, they can be programmed to deliver pacing stimuli only if the intrinsic heart is below some programmable rate. Therefore, the pacemaker only paces when it is needed, thereby minimizing unnecessary battery depletion and optimizing efficient cardiac performance. Programming of the pulse generator is accomplished using pacemaker system programmer that communicates with the pulse generator using radio waves emitted through a wand placed over the skin overlying the implanted pacemaker. Each manufacturer has a programmer that only works to communicate with its pacemakers. To learn more about pacemakers follow the links below.