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A normal heartbeat is created by electrical impulses that are generated within a specialized area of the heart and travel down specific pathways to stimulate the cardiac muscle to contract. If this natural “pacemaker” or any part of the conduction system is dysfunctional for some reason, the normal heartbeat may become too slow (bradycardia) or fast (tachycardia). These are abnormal heart rhythms, or arrhythmias. In some cases, physicians will recommend implantation of a pacemaker to correct an arrhythmia.
Pacemakers are electronic devices that may stimulate either the upper chambers of the heart (atria), lower chambers (ventricles) or both. In addition, some pacemakers are built with an internal device that can shock the heart back into a regular rhythm in the event a dangerous arrhythmia (implantable cardioverter defibrillator).
Pacemakers are most commonly used to correct an abnormally slow heartbeat by sending electrical impulses to one or more chambers of the heart. However, there are a variety of conditions that may call for pacing.
Pacemakers may be either permanent or temporary. A permanent pacemaker is implanted into a patient’s chest during a minor surgical procedure. A short stay in the hospital may be required, and some patients may need to take medications afterward that help the heart maintain a normal rhythm (antiarrhythmics). Once the pacemaker is in place, it runs on batteries that last for about 5 to 10 years. Pacemaker batteries will not run out unexpectedly. Physicians can detect when the battery is running low during a routine office visit.
Nearly 200,000 permanent pacemakers are implanted annually in the United States. People with pacemakers enjoy significant improvement in their quality of life. However, caution is advised in certain situations. While the risk of a life–threatening problem is small, people with pacemakers are encouraged to:
- Avoid walking through a metal detector, or spending any length of time near store security gates or entrances.
- Avoid magnetic resonance imaging (MRI) machines and tests.
- Hold cell phones at least 6 inches from the pacemaker at all times, even if the phone is turned off. Use and store the cell phone on the side of the body opposite the location of the pacemaker.
- Avoid any areas or equipment that generate strong electrical or magnetic fields, such as slot machines, remote-control toys, amusement park rides and attractions, power plants, junk yards that use large magnets, stereo speakers (when held close to the pacemaker), or poorly shielded car engines.
- Avoid working on car engines while they are running.
Temporary pacemakers are often used in emergency settings, or in the case of severely symptomatic bradycardia or tachycardia. The goal with temporary pacing is to reestablish a normal heart rhythm until a more permanent therapy can be launched, or until the condition causing the abnormal heart rhythm resolves. Patients on temporary pacemakers require constant monitoring.
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