Treatment with an artificial cardiac pacemaker has made great strides in becoming safer and applicable to a larger group of patients. An electrical device, the pacemaker, is surgically implanted to override or supplement the heart's own pacemaker and electrical conduction system. The treatment may be used for temporary assistance or for long-term therapy of abnormal heart rhythms.
The pacemaker weighs about 1.5 ounces and is powered by a lithium battery, which can last up to 10 years. The pacemaker is placed beneath the skin, just below the collarbone on the right side of the chest. One type is connected to an insulated wire lead that is passed through a large vein into the right side of the heart. Most often, this type of pacemaker is required in treatment of bradycardia (abnormally slow heartbeat). The pacemaker is programmed to sense when the heart's rate drops below a pre-set limit and to discharge an electrical impulse to the heart wall. These limits can be set and re-set by the physician after the pacemaker is implanted. A two-wire model may be used to correct sequence problems by making sure the atria contract before the ventricles in every cardiac cycle.
Pacemakers used today are very different from models used 10 and 20 years ago. Today, most patients no longer need to worry about electrical interference from such appliances as microwave ovens. However, caution is still important when you may be exposed to high voltage transmission lines and sub-stations, arc welding and magnetic resonance imaging technology. It is also important to protect the pacemaker and insertion site from injury due to a hard blow to the chest or sustained, extreme pressure against the chest.