Who Is a Candidate for a Pacemaker?

A pacemaker is a small, implantable electronic device used to monitor the heart’s electrical activity. If the normal rhythm is disrupted, or if the beat slows down, the pacemaker sends an electrical signal to restore the heart’s normal rate and rhythm.

The device contains a small generator and insulated wires, called leads. The doctor implants the generator under the skin near your heart, then connects the leads to the generator. Finally, they run the wires through a large vein and into one or more of the heart’s chambers, depending on the nature of your problem.

An electrode at the end of the lead touches the heart’s wall, which allows it to sense the heart’s electrical activity. It sends that information to the generator, and the generator responds by sending out an electrical impulse to the heart, when needed, to correct the rate.

At Northwest Houston Heart Center, cardiologists Dr. A. Adnan Aslam and Dr. Roy Norman diagnose and treat all manner of heart conditions at their offices in Tomball, Cypress, Magnolia, and The Woodlands, Texas. For their patients with fast, slow, or irregular heartbeats, they may recommend a pacemaker to help the heart return to proper function. In this blog, they discuss what conditions require a pacemaker and who might be a good candidate to get one.

The normal heart

The heart is a fist-sized muscle located in the middle of your chest and tilted slightly to the left.

Every day, your heart beats around 100,000 times. The blood pumped from the heart delivers oxygen and nutrients to the body’s tissues to help your organs and muscles work properly. On its return trip, the blood carries away unwanted carbon dioxide and other waste products.

Your heart has a left side and a right side, divided by the septum, a thin muscular wall. Both sides have an upper chamber and a lower chamber. The upper chambers are the left and right atria, and the lower chambers are the left and right ventricles.

The right side of your heart receives the deoxygenated blood being returned from your body, which it pumps to your lungs to pick up more oxygen. The left side of your heart pumps the re-oxygenated blood back around your body.

The heart’s electrical system determines when each chamber of the heart contracts and when it relaxes so blood is pumped regularly. The signals are generated in the right atrium’s sinus node, which is essentially your heart’s natural pacemaker. Usually, the sinus node sends the signals at a steady pace, but that pace can change depending on if you’re active or resting, or if you get emotional and what that emotion is.

What is bradycardia?

Bradycardia is the term for a slow heart rate. Adult hearts at rest usually beat 60-100 times a minute. With bradycardia, your heart beats fewer than 60 times a minute.

A slow heart rate isn't always a problem. A heart rate of 40-60 beats a minute is quite normal when you're asleep. In some people, such as healthy young adults and trained athletes, it's also normal when they're awake. Bradycardia causes no symptoms or complications in these cases.

However, bradycardia is serious if your heart rate is very slow and your heart can't physically pump enough oxygenated blood to nourish the body. If this happens, you may get dizzy, tired, weak, and short of breath.

Bradycardia can be caused by many things:

• Changes in the heart from getting older
• Physical activity: Endurance athletes often have slow heart rates.
• Diseases that damage the heart's electrical system, such as heart attacks and infections
• Conditions that slow electrical impulses, such as a low thyroid level (hypothyroidism) or an electrolyte imbalance, such as too much blood potassium

Different types of medicines, such as chemotherapy, heart medications, and opioids, can also slow the heart rate. If your doctor finds such an effect, they may switch you to a different medication for safety reasons.

When does a pacemaker come in?

Your doctor may recommend a pacemaker when you have bradycardia, tachycardia (an abnormally fast heartbeat), or an arrhythmia to stabilize the heart’s function. Atrial fibrillation, which triggers a chaotic heartbeat, is one of the most common arrhythmias for which a pacemaker is used.

You may also need a pacemaker if your heart can’t pump enough blood, as is the case with enlarged heart muscles (cardiomyopathy) or congestive heart failure. Some people need a pacemaker following a heart attack.

The pacemaker may have 1-3 leads, depending on how many of the heart’s chambers have a problem. 

Want to learn more about pacemakers and see if you’re a good candidate? Come into Northwest Houston Heart Center for an evaluation. To start, give us a call at any of our locations, or book online today. You can also text us at 832-402-9518.