What Is a Heart Pacemaker?

Millions of people worldwide live with a pacemaker that regulates their heartbeat, but exactly what are these devices and how do they work?

Pacemakers can save the lives of heart patients by preventing conditions like bradycardia, or a slow heart rate. Since the invention of the pacemaker in 1960, improvements to their original technology have been underway. Researchers are developing tech-forward devices like leadless pacemakers, pacemakers so small no surgery is needed, and even pacemakers that can dissolve once they are no longer needed.

A pacemaker is a small device that is implanted underneath the skin to help regulate your heartbeat with electrical impulses. It consists of a small, battery-powered generator and one or more leads that are placed directly in the heart.

“Pacemakers are designed just to keep the heart from going too slow…that’s the simplest type of cardiac implantable electronic device,” cardiologist Dr. Bruce Wilkoff explained in a Cleveland Clinic interview. The generator sends electrical impulses to the heart, keeping it beating at a regular pace. Pacemaker implantation can be permanent or temporary.

The type of pacemaker used will depend on a patient’s heart problem, according to the Cleveland Clinic. Pacemakers contain one to three leads that connect to ventricles or atria, which are the chambers of the heart. Pacemaker types include:

• Single-chamber pacemakers: These devices have one lead connected to one chamber of the heart. They treat conditions like bradycardia.

• Dual-chamber pacemakers: These devices have two leads, one connected to the right atrium and one connected to the right ventricle. They treat conditions like atrioventricular blocks (partial or complete interruption of electrical impulses from the atria to the ventricles).

• Biventricular pacemakers: These devices have three leads, one connected to the right atrium, and the other two to the lower chambers. They are used to treat more advanced conditions like heart failure.

A pacemaker works by sending electrical impulses to the heart to maintain a regular heartbeat. The generator is connected to the heart via leads, which detect the heart's natural electrical activity. If the heart beats too slowly, too quickly or irregularly, the pacemaker sends electrical impulses to the heart to help it beat at a regular, healthy pace.

The type of surgery will depend on the type of pacemaker that will be implanted, according to the Cleveland Clinic. Traditionally, pacemaker surgery is a minimally invasive procedure that is usually performed under local anesthesia, so you are awake for the surgery. A small incision is made in the chest and the generator is implanted under the skin, then connected to the heart via leads. The leads are passed through a vein and positioned in the heart. The procedure typically takes about an hour and patients can go home the same day.

A defibrillator and a pacemaker are two different, but similar, devices, according to the Cleveland Clinic. Generally, pacemakers treat bradycardia, or a slow heartbeat, and implantable cardiac defibrillators (ICDs) can treat tachycardia, or fast heartbeats.

If you have a pacemaker, there are certain things that should be avoided to prevent damage to the device, according to the Mayo Clinic. Some of these include:

• Avoid strong magnets: Strong magnets can cause a pacemaker to deliver inappropriate shocks or completely stop the pacemaker from working.

• Avoid certain activities: Contact sports like football and rugby, and activities that involve heavy lifting like weightlifting, should be avoided to prevent device damage.

• Avoid certain equipment: Things like cellphones, metal detectors, MRIs, CT scans, radiation treatment for cancer, electric blankets and heating pads can also interfere with pacemaker function and should be avoided.

For more information on cardiovascular diseases, check out these additional resources:

What Is a Heart Attack and What Are the Symptoms?

What Is Coronary Heart Disease?

What Is Congestive Heart Failure?

Irregular Heartbeat: What Is It and How Do You Treat It?