Pacemaker: What does the Data Say?

May 2021

A pacemaker is a medical device that helps synchronize the heart's electrical impulses or make a heartbeat stronger when it's too slow. It monitors and responds to your body's changing needs for oxygen and calories. It can be implanted inside your chest, under the collarbone, or near your collarbone with wires going through the skin to the electrodes on the heart that are inserted through small cuts in your skin.


Why you might need a pacemaker:
Your heart normally beats about 70 times per minute. But as you get older, your heart rate slows down. A pacemaker can help keep your heartbeat strong and steady. If your heart doesn't beat fast enough, it won't get the oxygen it needs to stay healthy. And if it doesn't beat fast enough for too long, it may stop altogether--just like a car battery runs out of gas. A pacemaker can bring life back into any failing or tired heart.


Who you are:

 If you: Are over 65 years old? Have heart failure or a weakened heart? Have a heart rhythm problem (arrhythmia) like atrial fibrillation, ventricular fibrillation or cardiac arrest? Have a history of sickle-cell disease or other blood disorders?


What might need to be done to get the device:
A pacemaker may not be the best option for you. It's not likely to help your heart beat faster, and it could make your condition worse. You may still need other treatments. We'll talk with you about what else we can do for you.


I'm healthy and energetic. I don't have heart problems. Will a pacemaker change that?


It's true that not everyone needs a pacemaker. You will need to see a doctor for an examination and tests to see if you can get one. A Pacemaker is only for people diagnosed with heart disease or slow heart rhythm. If you're healthy and don't have any heart problems, it's not likely to help you. And it may interfere with other tests your doctor may want to do on your heart in the future.


A pacemaker is a small, powerful device that provides intermittent electrical pulses to the heart to make it beat faster or slower, or sometimes stop it completely. This is called pacing. These pulses are triggered by electrical signals from an artificial nerve in the chest wall or a sensor on the heart muscle. The first implantable pacemaker was created by Dr. Paul Zoll of Harvard Medical School and tested in 1958 on a patient with atrial fibrillation (irregular heartbeat). The U.S. Food and Drug Administration approved the first external model in 1960 as well as the first internal model in 1962.


Pacemakers are programmed to provide a specific type of electrical stimulation for the heart: a strobe (a single, fast pulse), a constant (steady, slow pulse) or a mixture of the two. The user can then select and change how often the pulses are delivered. The pulse strength and duration can also be adjusted. In addition to selecting parameters, the user also has to select an appropriate mode. There are three modes: monomorphic (same pattern for all pace rates), biomorphic (one pattern sets all pace rates) and isodynamic (two patterns -- one for rate of atrial fibrillation and one for rate of normal sinus rhythm). Monomorphic and bimorphic pacemakers can be used for both atrial fibrillation and normal sinus rhythm.


The user usually has to do this selection when the device is implanted or after the battery is replaced, which requires a visit to the doctor. Some of these parameters can also be adjusted through a wireless device similar to a small cell phone. This is called telemetry. Telemetry allows patients or doctors to change some parameters wherever they are (in doctors' offices, hospitals -- anywhere). This helps customize pacing for different levels of physical effort.


One of the big challenges of these devices is that they can malfunction. Every American population has one chance in a million to have a pacemaker malfunction. This means that if you are in an individual Medicare or Medicaid plan, you have every chance to get one implanted wrong, or with too much energy (too much electricity, too strong a stimulus) or not enough energy (not enough strength) for you to get any benefit from it. Some doctors and patients choose not to take this risk and avoid pacemakers (or use them only when there is no alternative).

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