Pacemaker Implantation

Your heart has an electrical system that controls the rate and rhythm of your heartbeat. In a normal heartbeat, the heart’s two upper chambers, the atria, contract first. This pumps blood into the heart’s two lower chambers, the ventricles. The ventricles then contract and pump blood to the rest of the body. The combined contraction of the atria and ventricles is a heartbeat.

A variety of conditions can block or disrupt the heart’s electrical signals. The result can be arrhythmia—problems with the rate or rhythm of the heartbeat. During an arrhythmia, the heartbeat can be too fast, too slow, or irregular. A heartbeat that’s too fast (over 100 beats per minute) is called tachycardia. A heartbeat that’s too slow (under 60 beats per minute) is called bradycardia. An irregular heartbeat is called dysrhythmia.

For the heart to work correctly, the chambers must beat in a coordinated pattern at a resting heart rate between 60 and 100 beats per minute.

With each heartbeat, an electrical signal begins in a group of cells called the sinus (or sinoatrial) node. As the signal starts at the top of the heart, it coordinates the timing of each beat.

First, the heart’s two upper chambers, the atria, contract. The electrical signal then moves through the heart to the atrioventricular (AV) node, another cluster of specialized cells in the center of the heart between the atria and ventricles (the heart’s lower chambers). From the AV node, the electrical current travels along special fibers to the ventricles, which contract and pump blood to the body. The combined contraction of the atria and ventricles is a heartbeat.

During an arrhythmia, the heart may not be able to pump enough blood to the body. This can cause symptoms such as fatigue, shortness of breath, or fainting. Severe arrhythmias can damage the body’s vital organs and may even cause loss of consciousness or death.

A pacemaker can relieve arrhythmia symptoms such as fatigue and fainting, helping a person with arrhythmia resume a more active lifestyle. More severe arrhythmias may require a pacemaker that includes an implantable cardiac defibrillator.

Pacemakers are very small battery-powered computers that are implanted just under the skin, usually in the chest area, to support the heart’s electrical system. The device has very thin wires, called leads, that are threaded through a blood vessel into the heart. The pacemaker sends electrical pulses through the leads to maintain a normal heartbeat. These impulses are very tiny, and most people do not feel them at all. While the device helps your heart to maintain its rhythm, it also stores a lot of information about your heart that can be retrieved by your doctor. This helps him program your device so that it provides with the best therapy for your condition.

The device is implanted under the skin just below the collarbone, usually on the left side.

Your doctor will conduct a comprehensive evaluation that includes a history, a physical examination, and an electrocardiogram (to measure your heart’s electrical impulses); you may also require a nuclear stress test, cardiac catheterization, and/or cardiac MRI.

It’s about the size of two stacked half-dollars. Smaller units are currently in clinical trials.

It depends on the person and on the type of implant. If you’re thin, it generally will protrude more. If you have a little more bulk it will be less obvious. The device can be implanted under the breast muscle, which would prevent it from being seen. Speak to your doctor about options for your implant location.

No. Your life will only change if you allow it to. The pacemaker won’t hinder you or your activities that you do.

Serious risks are very rare (1%), but they include stroke, heart attack, and possible damage to the heart or lungs. At least some of this risk depends on the patient’s overall condition.

Other risks are infection at the implant site, allergic reactions, and swelling, bruising, or bleeding at the implant site, especially for patients who take blood thinners.

Electromagnetic frequencies can interfere with the pacemaker’s ability to sense an abnormal rhythm. Generally, you just need to maintain a certain distance to avoid interaction.

These devices are safe to use:

• Microwave ovens
• Computers
• DVR players
• Small electrical tools
• Garage door openers

Use caution around these devices:

• Anti-theft security systems: These are unlikely to create any interference as you walk through them, but you should be aware of their locations.
• Cell phones, Bluetooth headphones, and MP3 players (iPods): Keep these at least 6 inches away from your pacemaker. Hold the phone on the ear opposite your pacemaker.
• Airport security scanners: When traveling in an airport, tell security you have a pacemaker and request a manual search.
• Medical devices and procedures: Tell your dentist and other health care providers that you have a pacemaker before they perform any tests or procedures. Normal teeth cleanings are safe and require no special instructions.

Avoid these devices:

• Large generators
• Electrical transformers
• Large machinery