he pacemaker has two parts: the leads and a pulse generator. The pulse generator houses the battery and a tiny computer, and resides just under the skin of the chest. The leads are wires that are threaded through the veins into the heart and implanted into the heart muscle. They send impulses from the pulse generator to the heart muscle, as well as sense the heart’s electrical activity.
Each impulse causes the heart to contract. The pacemaker may have one to three leads, depending on the type of pacemaker needed to treat your heart problem.
There are different types of pacemakers:
Single chamber pacemakers use one lead in the upper chambers (atria) or lower chambers (ventricles) of the heart.
Dual chamber pacemakers use one lead in the atria and one lead in the ventricles of your heart.
Biventricular pacemaker uses three leads: one placed in the right atrium, one placed in the right ventricle, and one placed in the left ventricle.