Pacemaker Types

A pacemaker is an electronic device equipped with a battery, electronic circuits and computer memory that generates electronic signals (pacing pulses), which are carried along insulated wires (leads) to the heart to make the muscle beat at a normal rhythm. Bradycardia, a heartbeat that slows to an unhealthy rate, is the most frequent reason for a pacemaker. There are three basic types of temporary or permanent pacemakers, and each may work on demand, constantly or according to the heart's activity.

Single-chamber Pacemakers

• With a single-chamger pacemaker, one lead is placed into a chamber of the heart. This lead is placed either in the upper chamber (right atrium) or the lower chamber (right ventricle).

Dual-chamber Pacemakers

• In dual-chamber pacemakers, two leads are placed into the heart. One is placed in the atrium and the other in the ventricle. This type of pacemaker more closely mimics a natural heart rate.

Triple-chamber Pacemakers

• With a triple-chamber pacemaker, one lead usually goes to the right atrium and another stimulates both the right and left ventricles. They work to resynchronize the ventricles in a weakened heart.

Demand Pacemakers

• When the heart's rate is too slow or it misses a beat, demand pacemakers, which monitor the heart's activity, will send an electrical pulse to set the heart back to a more normal rhythm.

Fixed-rate Pacemakers

• Fixed-rate pacemakers discharge steadily, regardless of the heart's natural electrical activity.

Rate-responsive Pacemakers

• Rate-responsive pacemakers have sensors that adjust automatically to changes in your physical activity. They are designed to raise or lower the heart rate to meet the body's needs.

Temporary Pacemakers

• Temporary pacemakers are typically used during hospitalization and are used only short-term. The pulse generator is either taped to the skin or attached to a belt and remains outside of the body.

Permanent Pacemakers

• Permanent pacemakers are used for conditions that are lasting or persistent and are required long-term. The pulse generator is implanted under the skin. One end of each lead is attached to the generator, while the other end is inserted into a main vein and moved forward until the electrode is in the proper region of the heart.

ICDs

• Implantable cardiac defibrillators (ICDs) are designed primarily for the purpose of preventing sudden death from cardiac arrest due to abnormally fast heart beats (tachycardias). ICDs monitor the heart rhythm, and when the beat is normal, the device remains inactive. If a tachycardia develops, the ICD sends an electrical shock to the heart to stop the abnormal rhythm and return the heartbeat to normal.

  ICDs are not pacemakers but have been used as such in certain situations.

Warnings

• A cell phone should not be carried in a pocket that is close to or over the pacemaker, because if placed directly over the pulse generator, it can cause interference with the pacemaker, especially the antenna.

  Electromagnetic antitheft security systems found in the workplace, at airports and in stores have been known to cause interference with some pacemakers. However, this depends on the duration of exposure and the distance between the system and the pacemaker. Often they are not an issue, and people with pacemakers need only to be aware of antitheft systems and move through them at a normal pace.

  Certain medical procedures may interfere with pacemakers. MRIs, therapeutic radiation, diathermy (electromagnetic radiation that heats body tissues) and other procedures might cause problems with your pacemaker. You should inform all health care providers about your pacemaker.

  Full-contact sports aren't recommended, as they can damage a pacemaker.