A pacemaker is a man-made device that causes the heart to beat when it has difficulty beating normally on its own.
The heart contains a special electrical system that allows it to beat regularly. But sometimes certain conditions, such as sick sinus syndrome and heart block, damage this system so that the heart may not beat correctly on its own. If the heart rate become too slow, the heart cannot pump enough blood to meet the body's needs.
When this occurs, a pacemaker can be used to make the heart beat faster. A pacemaker delivers a tiny spark of electricity to the heart to make it beat. A pacemaker is a battery-operated device that is usually placed under the skin of the chest. It is connected to a wire that is threaded through one of the main veins of the body into the heart. The end of the wire is attached to the heart itself. When the pacemaker "fires," the electricity goes directly into the heart and causes it to beat or to stop beating abnormally.
The wire can also sense when the heart beats normally or abnormally, helping the pacemaker "decide" when to fire. Putting the pacemaker under the skin of the chest allows easy access when the device needs service.
There are many different types of pacemakers. Some only help the heart beat when it gets too slow. Other pacemakers make the heart beat at all times. Special pacemakers can be used to deliver a shock to the heart when an abnormal heartbeat occurs. This shock often corrects the abnormal heartbeat. The type of pacemaker a person uses depends on his or her needs.
Most advanced devices can sense things like the breathing rate or the amount of muscle activity in the body. This can be helpful during exercise, when the breathing rate increases and the body needs the heart to pump more blood. In this way, a person can exercise without getting tired or short of breath.
Pacemaker generators generally last from 5-10 years. In some emergency cases, temporary pacing devices can be used prior to placement of a permanent pacemaker. Placing a permanent device involves minor surgery. After a person recovers from surgery, the function of the pacemaker is carefully checked. Adjustments to the pacemaker settings can be made at any time, with a portable programming device.
Most people can return to their normal lives after a pacemaker is inserted. People with pacemakers need to know a few things to prevent pacemaker malfunction. Generally speaking, strong magnetic fields and electrical shocks should be avoided. Large generators should be kept at a safe distance. Large magnets, such as those found in stereo speakers, should not be handled. Most household electric and electronic devices are safe.
Any healthcare professional who cares for the person must be told about the presence of a pacemaker. It is an important factor when the professional decides to order treatments or tests. Certain medical tests, such as a special x-ray test known as an MRI, need to be avoided. Other procedures, such as radiation therapy for cancer, should be discussed with the professional beforehand.
Dentists should also be advised of a pacemaker. Most dental procedures can be safely done on people with pacemakers. Most other activities are allowed. However, contact sports should be avoided.
Airport and other security systems will not damage the pacemaker, but it may set off security alarms. Any time a person is concerned about their pacemaker or a potential problem with it, the healthcare professional should be contacted.
Follow-up care is a very important part of having a pacemaker. A pacemaker needs regular check-ups when adjustments can be made and the battery can be checked. Home-based monitoring by telephone has become common. This type of monitoring allows the pacemaker to send data over the telephone. In this way, the pacemaker can be checked without requiring the person to come into the office.
A person should call his or her healthcare professional right away if symptoms of fainting, dizziness, shortness of breath or chest pain occur. Pacemaker batteries can last for years, but do eventually wear out. When the battery weakens, a safety feature will alert the person and the healthcare professional so that it can be replaced -- a minor surgical procedure. Pacemaker wires may sometimes need to be repositioned or replaced as well.
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Heart Disease: A Textbook of Cardiovascular Medicine, Braunwald, E. 1980