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Detailed Description of a Pacemaker

A cardiac pacemaker, also known as an artificial or internal pacemaker, is a small implantable device that sends electrical impulses to your heart to ensure that it maintains a normal and healthy rhythm at all times. If you have had to live your life on the sidelines since developing a problem with abnormal heart rhythms, a pacemaker will allow you to get back into the game and enjoy a more fully rounded life.

  1. Size

    • Perhaps the most striking feature about a pacemaker is its tiny size, particularly when one considers the huge role it must play in keeping the heart beating normally. It has to be small, of course, to easily fit under the skin of your chest or abdomen where it will remain on duty without a battery change for up to eight years. A typical pacemaker weighs slightly less than an ounce--30 grams to be precise--and is about the size of a small pager.

    Key Components

    • The key parts of a pacemaker, according to the National Heart, Lung and Blood Institute, are a computerized generator, battery and electrical leads, each of which has an electrode on its end. The generator and battery are housed together in a thin metal case, and the leads, or wires, extend from the case and are connected to the heart itself.

    How It's Implanted

    • The implantation of the pacemaker involves minor surgery. The first order of business is connecting the pacemaker's leads to the heart. To do this, the surgeon inserts a needle into a large vein, usually in the shoulder. Using the needle, the surgeon threads the thin leads through the blood vessels until they reach the heart, where they will be attached. Next a small incision is made in the skin of the abdomen or chest. The main body of the pacemaker is inserted through that incision, after which the leads are connected to the device. Once the device is in place, the incision is sutured, and the procedure is complete.

    How It Works

    • The computer in the pacemaker's generator constantly monitors the heart's activity and sends electrical impulses to the heart to ensure that it beats normally. This prevents arrhythmia, a potentially fatal irregularity in heart rhythm. Pacemakers also are used in patients who have bradycardia, characterized by a consistently slow heart beat and usually caused by a heart muscle weakened by disease or injury. For such patients, the pacemaker restores normal heart rhythm.

    Maintenance

    • Although a pacemaker's power source may last for up to eight years, your doctor will regularly check the device's battery and its record of heart activity and pacemaker intervention. You must make a few adjustments in your lifestyle, one of which is the avoidance of close or prolonged contact with other electrical devices or anything that has a strong magnetic field. You should steer clear of electrical generators, high-tension wires, metal detectors, industrial welders, cell phones and certain appliances, most notably microwave ovens. Also avoid such medical procedures as magnetic resonance imaging and electrocauterization.

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