When the old ticker begins to slow down, medical technology has a way to keep it ticking. It's called a pacemaker, and new advances have enabled it to mimic the rhythm of the heart more closely than ever before.

  A pacemaker is about the size of two silver dollars sandwiched together. It weighs less than an ounce and contains a sophisticated computer chip that regulates a malfunctioning heart rhythm by sending pulses of energy to the heart.

  Approximately 140,000 of these devices were implanted in the United States in 1993. Patients with slow heart rhythm disorders are candidates for the pacemaker. Some people are born with this disease, while others may acquire it as a result of a heart attack or other disorder later in life. 

  A heart affected by a slow heart rhythm fails to speed up naturally in response to increased activity or exercise. As a result, these individuals may not get enough oxygen-enriched blood to the brain or other vital organs. This can cause a variety of problems including fatigue, light-headedness, fainting and shortness of breath. A properly programmed pacemaker can relieve these symptoms.

  Pacemakers have become much more sophisticated since 1958 when the first pacemaker -- a bulky, hockey puck-sized device — was successfully implanted in man. Implanting the device required an open heart operation and its capabilities were very limited. One of its biggest failures was its inability to keep up with a person's increase in activity level. 

  Today's pacemaker provides no impairment in lifestyle, and can actually improve quality of life. Technological advances allow today's pacemaker to sense and respond to changes in activity by monitoring a person's breathing, temperature, pulse or motion. Each pacemaker is custom-tuned to fit the individual needs of the patient and can be adjusted to accommodate lifestyle changes. 

  Implanting a pacemaker is usually a simple procedure that requires a brief hospital stay. Surgery normally takes about an hour and is done under a local anesthetic. A small incision is made in the shoulder area where the pacemaker is placed. A thin wire called the lead is then inserted into a vein and threaded from the generator to the heart where the tip of the lead rests against the inner heart wall. 

  Most pacemakers will last at least five years before the battery wears down, which requires replacement of the generator. This can be accomplished in a simple outpatient procedure performed with a local anesthetic.
Monitoring Is Important 

  To optimize the quality of life for the patient and the life of the pacemaker, regular monitoring of the pacemaker is important to keep it programmed correctly. This can be done during regular physician office visits. Alternatively, the patient may be able to send heart rhythm and pacemaker function data to the doctor via telephone or other special transmitter. 

  Adjustments to the pacemaker are done non-invasively and should be performed by someone trained in pacemaker technology. If you experience a loss of energy, light-headedness or dizziness, it may indicate pacemaker failure. Your physician should be notified immediately.
Interaction With Other Technology 

  Individuals with a pacemaker may receive X-rays, computed tomography (CT) scans and ultrasound tests without posing a problem. However, magnetic resonance imaging is not recommended. Anytime a pacemaker patient must undergo any type of testing, the physician should made aware of the pacemaker. 

    Pacemaker patients should also be able to use microwave ovens as well as almost any home appliances or electronic devices. Although theft-detection systems and airport metal detectors should not affect a pacemaker's function, a pacemaker identification card should be carried in case there is a problem.