What Is A Pacemaker

Pacemakers are devices, which are implanted under the skin, usually in the upper chest below the collarbone and are used to monitor and treat heart rhythm disturbances. Flexible wires called leads carry electrical impulses to the heart muscle. Pacemakers regulate the heartbeat by triggering slow heart rhythms.

• A pacemaker is composed of three parts: a pulse generator, one or more leads, and an electrode on each lead. A pacemaker signals the heart to beat when the heartbeat is too slow or irregular.

• A pulse generator is a small metal case that contains electronic circuitry with a small computer and a battery that regulates the impulses sent to the heart.

When Is A Pacemaker Needed

A pacemaker is indicated when there are signs that your heart is not beating fast enough or there is a problem with the normal electrical signal, which causes your heart to beat. When the timing of the electrical stimulation of the heart to the heart muscle and the subsequent response of the heart’s pumping chambers is altered, a pacemaker may help.

Some problems that may require the use of a Pacemaker include:

• Bradycardia: failure of the SA node to send out adequate electrical signals resulting in a slow heart rate

• Heart Block: a block in or below the AV node which prevents the impulse from reaching the lower chambers of the heart

• Tachy-brady syndrome: abnormal heart rhythms characterized by alternating fast and slow heart beats that are not controlled by medications.

These disorders happen because something has gone wrong with the heart’s electrical system. It can mean heart rhythms that are too slow, too fast and too irregular. These rhythms may cause symptoms such as fainting (syncope) or feeling fast or irregular heartbeats (palpitations).

If the heart’s rate is slower than the programmed limit, an electrical impulse is sent through the lead to the electrode and causes the heart to beat at a faster rate. When the heart beats at a rate faster than the programmed limit, the pacemaker generally monitors the heart rate and will not pace. Modern pacemakers are programmed to work on demand only, so they do not compete with natural heartbeats. Generally, no electrical impulses will be sent to the heart unless the heart’s natural rate falls below the pacemaker’s lower limit

• After a pacemaker insertion, regularly scheduled appointments will be made to ensure the pacemaker is functioning properly. The doctor uses a special computer, called a programmer, to review the pacemaker’s activity and adjust the settings when needed.

Pacemaker Precautions

The following precautions should always be considered. Discuss the following in detail with your doctor, or call the company that made your device:

• Always carry an ID card that states you have a pacemaker.

• Let screeners know you have a pacemaker before going through airport security detectors. In general airport detectors are safe for pacemakers, but the small amount of metal in the pacemaker and leads may set off the alarm

• You may not have a magnetic resonance imaging (MRI) procedure (unless you have a specially designed pacemaker). You should also avoid large magnetic fields such as power generation sites and industrial sites such as automobile junkyards that use large magnets.

• Abstain from diathermy (the use of heat in physical therapy to treat muscles).

• Turn off large motors, such as cars or boats, when working close to them as they may create a magnetic field.

• Avoid high-voltage or radar machinery, such as radio or television transmitters, electric arc welders, high-tension wires, radar installations, or smelting furnaces.

• If you are having a surgical procedure performed, inform your surgeon that you have a pacemaker well before the operation.

• When involved in a physical, recreational, or sporting activity, protect yourself from trauma to the pacemaker functioning. If you are hit in that area, you may want to see your pacemaker clinic.

• Cell phones with less than 3 watts of output do not seem to affect pacemakers or the pulse generator, but as a precaution, cell phones should be kept at least 6 inches away from your pacemaker. Consult Your Doctor.

Always consult your doctor when you feel ill after an activity, or when you have questions about beginning a new activity.

Always consult your doctor if you have any questions concerning the use of certain equipment near your pacemaker.

Pacemaker Evaluation is available at the Heart Foundation of Jamaica- Call for an appointment.

Contributed by: Dr. Noel Crooks, Interventional Cardiologist, The Heart Foundation of Jamaica.