What is a Pacemaker?

Irregularities in the heart's natural pacemaker can lead to low blood pressure.
Some patients who experience irregularities in their heart rhythm require the assistance of a pacemaker.
A pacemaker permanently monitors the heart's rhythm in both the atria and ventricles.
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  • Written By: R. Kayne
  • Edited By: L. S. Wynn
  • Last Modified Date: 22 September 2014
  • Copyright Protected:
    2003-2014
    Conjecture Corporation
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A pacemaker is a medical device that keeps the heart beating normally, commonly implanted in patients with bradycardia. Bradycardia causes an unusually slow or irregular heartbeat.

In a healthy heart, the beat begins in the right atrium or upper chamber as an electrical impulse. This impulse travels through the heart tissues to the ventricle or lower chambers. Here the heart muscles contract in response to the beat, pumping oxygen-rich blood throughout the body and lung tissues. If blood is pumped too slowly for the body's needs, dizziness, lightheadedness and fainting can occur. A pacemaker alleviates this problem by regulating the heartbeat.

A pacemaker is a small, battery operated, titanium device with one or more highly flexible pacing leads. It is implanted in the chest area with the lead(s) running down to the heart. A lead might be inserted into a vein that feeds into the desired chamber, or it might be affixed to the outside of the heart if the heart is still growing as in the case of children. The tip of the lead is fitted with an electrode and the pacemaker contains a computerized program that can stimulate a heartbeat through sending a pacing pulse to the electrode.

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Bradycardia can manifest in one of two ways that might affect the type of pacemaker used. In some cases the heart's own pacemaker -- the sinus node -- simply does not generate enough beats per minute, creating low blood pressure and an abnormally slow heartbeat. This is known as sick sinus syndrome.

In other patients, only some of the heartbeats that are generated reach the ventricle chamber, and thus no blood is pumped for the missed beat. This condition is known as heart block and can be caused by scar tissue, heart disease or other abnormalities that interfere with the travel of the impulse, creating an irregular heartbeat.

If bradycardia is present as one of the above conditions, a single-chamber pacemaker might be used to stimulate the faulty chamber. If both sick sinus syndrome and heart block are present, a double-chamber pacemaker can be used to generate beats in the atrium and initiate contraction for pumping blood in the ventricle.

An external programming unit retained by the physician can communicate with the pacemaker during checkups. Information about the condition and health of the heart can be relayed and the pacemaker's internal program can be altered as necessary without surgery.

Pacemakers have been used since the 1950s and come in various models. Older styles were designed to deliver beats at a predetermined rate. Other models use sensors that monitor the heart, only generating a pace or beat when the heart's own beat becomes too slow or irregular. Dual-chamber pacemakers monitor both upper and lower chambers, ensuring they remain synchronized in a natural rhythm. The most advanced pacemakers are rate-responsive. These pacemakers monitor the body's needs so that the heartbeat quickens on demand —- say for strenuous exercise —- and automatically slows when the body is at rest and demands are low.

A pacemaker can make life immeasurably better for someone living with bradycardia, allowing an active life without feeling tired or lacking in energy. With advanced technology in micro circuitry, pacemakers are becoming smaller and more powerful. Speak to your physician about the options available for your specific needs.

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Discuss this Article

irontoenail
Post 3

@pleonasm - By the time they are at the point where they think it's a good idea to put in a pacemaker, there really isn't going to be any other choice. And I'm not sure how they could study the long term effects ethically, because there would be no way to have an ethical control group without possibly condemning some people to living without a pacemaker, which can mean great discomfort or death.

Maybe it does eventually encourage the heart to stop working, but the hearts of pacemaker patients are already going that way. The pacemaker procedure has saved so many lives including those of a lot of people I know, that I don't think it matters. It is a long term solution that works.

pleonasm
Post 2

@croydon - I wonder if they have ever done any studies on whether or not having a pacemaker actually trains the heart to stop working on its own. It wouldn't surprise me if that was the case, which is a bit frightening really because no matter how wonderful the pacemaker is, you still have to get it checked and have the batteries changed every now and then, so you're basically dependent on the doctor for that.

croydon
Post 1

My mother was fitted for a cardiac pacemaker a couple of years ago. It made such a huge difference it was amazing. She had thought that she was just getting really unfit because she couldn't walk up a hill without having to stop to catch her breath multiple times. But when she finally went to the doctor about it they told her it was actually a symptom of heart problems, rather than fitness.

They still don't know why it happened in the first place, but I'm so glad they diagnosed it early before it became a serious problem. They've tried turning it off a couple of times recently and my mother basically fainted because her heart just can't beat on its own any longer.

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