An Overview of Implantable Cardiac Devices

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Implantable cardiac device (ICD) is a term used to describe a medical device that is placed within the heart to monitor or treat a condition within the heart. The machine is not only needed to alert the person or medical personnel of a problem occurring within the heart, the implanted machine can also be created to correct the medical problem as it is happening.

When discussing the history of an implantable device, keep in mind that the technology is fairly young, compared to other medical developments. The first machine implanted into the body was done in Sweden in 1958. Just like other technology, devices to be implanted are granted approval by the Food and Drug Administration (FDA) within the United States. Since 1958, at least 450,000 machines have been implanted.


One kind of implanted cardiac device is the defibrillator. These small machines work to improve the heart function in quite a number of people. The way in which these devices work is seen in the way they are attached to the heart muscle to defibrillate the heart.

What a defibrillator does is monitor the heart’s electrical activity and will respond when the heart rate reaches a high level. This is called tachycardia and the defibrillator will decrease the rate the heart beats. This device will only become active when the heart rate exceeds 100 beats per minute.


Another popular type of medical device are artificial pacemakers. It is well-known due to its ability to help monitor the heart after it has been damaged. The damage is usually due to a heart attack or trauma.

It is quite ingenious the way the pacemaker functions. The heart has its own “natural pacemaker” that sends electrical impulses to muscle to maintain the natural rate and rhythm of the heart. Therefore, the natural pacemaker helps to keep the heart beating.

However, when the natural pacemaker of the heart becomes damaged, the physician will opt to implant an artificial pacemaker. This device will keep the heart beating and save the person’s life. By doing so, the implantable machine can also keep the amount of blood flowing to the brain and other vital organs.

How Devices Are Implanted

The device to be implanted within the heart is done in surgery. This can be a lengthy surgery that lasts a minimum of two hours, but the heart muscle is not cut in the same way as with valve replacement surgery. Therefore, it is a “minor” type of heart surgery.

For example, to implant a defibrillator, the person is usually given a medication to numb the area. Afterward, the surgeon will then make an incision near the collarbone, and will place one of the electrodes into the heart muscle. The other end of the electrodes is attached to the machine and this is placed right near the collarbone.


MedicineNet: Implantable Cardiac Devices

Medscape: Implanted Medical Devices

National Library of Medicine: Pacemakers and Defibrillators