A pacemaker is a small device that’s placed under the skin of your chest or abdomen to help control abnormal heart rhythms. This device uses electrical pulses to prompt the heart to beat at a normal rate.
Pacemakers are used to treat heart rhythms that are too slow, fast, or irregular. These abnormal heart rhythms are called arrhythmias (ah-RITH-me-ahs). Pacemakers can relieve some symptoms related to arrhythmias, such as fatigue (tiredness) and fainting. A pacemaker can help a person who has an abnormal heart rhythm resume a more active lifestyle.
The Heart’s Electrical System
Electrical signals normally begin in a group of cells called the sinus node. As these signals spread from the top to the bottom of the heart, they coordinate the timing of heart cell activity. First, the two upper chambers of the heart, called atria (AY-tree-uh), contract. This contraction squeezes blood into the lower chambers of the heart, which are called ventricles (VEN-trih-kuls). The ventricles then contract and send blood to the rest of the body. The combined contraction of the atria and ventricles is a heartbeat.
For more information about the heart’s electrical system and how a healthy heart works, see the Diseases and Conditions Index article on How the Heart Works.
Overview
Faulty electrical signaling in the heart causes arrhythmias. A pacemaker uses low-energy electrical pulses to correct faulty electrical signaling. Pacemakers can:
- Speed up a slow heartbeat
- Help end an abnormal and fast rhythm (only in implantable cardioverter defibrillator/pacemaker combination devices)
- Make sure the ventricles contract normally if the atria are quivering instead of beating in a normal rhythm (a condition called atrial fibrillation)
- Coordinate the electrical signaling between the upper and lower chambers of the heart
- Coordinate the electrical signaling between the ventricles (cardiac resynchronization therapy used in heart failure)
Pacemakers also can monitor and record your heart’s electrical activity and the rhythm of your heartbeat. Newer pacemakers can monitor your blood temperature, breathing rate, and other factors and adjust your heart rate to changes in your activity.
Pacemakers can be temporary or permanent. Temporary pacemakers are used to treat temporary heartbeat problems, such as a slow heartbeat due to heart attack, heart surgery, or an overdose of medicine. Temporary pacemakers are used in emergencies until a permanent pacemaker can be implanted or until the temporary condition goes away. A person with a temporary pacemaker will stay in the hospital as long as the pacemaker is in place.
In this article, “pacemakers” refers to permanent devices, unless stated otherwise.
Doctors also treat arrhythmias with another device called an implantable cardioverter defibrillator (ICD). An ICD is like a pacemaker in some ways, but it can use higher energy electrical pulses to treat certain dangerous types of arrhythmia. For more information on ICDs, see the Diseases and Conditions Index article on Implantable Cardioverter Defibrillator.
Who Needs a Pacemaker?
Doctors recommend pacemakers to patients for a number of reasons. The most common reason is when a patient's heart is beating too slow or there are long pauses between heartbeats. Using pacemakers to treat conditions not related to heart rhythm problems is becoming more common.
A pacemaker may be helpful if:
- Aging or heart disease damages your sinus node's ability to set the correct pace for your heartbeat. Such damage can make your heart beat too slow, or it can cause long pauses between heartbeats. The damage also can cause your heart rhythm to alternate between slow and fast.
- You need to take certain heart medicines (such as beta blockers), but these medicines slow down your heartbeat too much.
- The electrical signals between your heart's upper and lower chambers are partially or completely blocked or slowed down (this is called heart block). Aging, damage to the heart from a heart attack, or other heart conditions can prevent electrical signals from reaching all the heart's chambers.
- You often faint due to a slow heartbeat. For example, this may happen if the main artery in your neck that supplies your brain with blood is sensitive to pressure. In you have this condition, just quickly turning your neck can cause your heart to beat slower than normal. When that happens, not enough blood may flow to your brain, causing you to faint.
- You have had a medical procedure to treat an arrhythmia called atrial fibrillation. A pacemaker can help regulate your heartbeat after the procedure.
- You have heart muscle problems that cause electrical signals to travel through your heart muscle too slow. (Your pacemaker will provide cardiac resynchronization therapy for this problem.)
To decide whether a pacemaker will benefit you, your doctor will consider any symptoms you have of an irregular heartbeat, such as dizziness, unexplained fainting, or shortness of breath. He or she also will consider whether you have a history of heart disease, what medicines you're currently taking, and the results of heart tests.
A pacemaker won't be recommended unless your heart tests show that you have irregular heartbeats.
Tests That Help Determine Whether You Need a Pacemaker
A number of tests are used to detect an arrhythmia. Your doctor may recommend some or all of these tests.
EKG (Electrocardiogram)
This simple and painless test detects and records the electrical activity of the heart. An EKG shows how fast the heart is beating and the heart's rhythm (steady or irregular). It also records the strength and timing of electrical signals as they pass through each part of the heart.
Holter Monitor
During the 24 or 48 hours, you do your usual daily activities and keep a notebook, noting any symptoms you have and the time they occur. You then return both the recorder and the notebook to your doctor to read the results. Your doctor can see how your heart was beating at the time you had symptoms.
The purpose of a Holter monitor is to record heart signals during typical daily activities and while sleeping, and to find heart problems that may occur for only a few minutes out of the day.
Echocardiogram
This test uses sound waves to create a moving picture of your heart. An echocardiogram shows the size and shape of your heart and how well your heart is pumping blood. The test can identify areas of heart muscle that aren't contracting normally or getting enough blood flow.
Electrophysiology Study
For an electrophysiology study, your doctor threads a small, flexible wire from a blood vessel in your arm or leg to your heart. The wire electrically stimulates your heart to see how your heart's electrical system responds. The electrical stimulation helps to find where the heart 's electrical system is damaged.
Stress Test
Some heart problems are easier to diagnose when your heart is working harder and beating faster than when it's at rest. During stress testing, you exercise to make your heart work harder and beat faster while heart tests, such as an EKG or echocardiogram, are performed.
How Does a Pacemaker Work?
A pacemaker consists of a battery, a computerized generator, and wires with electrodes on one end. The battery powers the generator, and a thin metal box surrounds both it and the generator. The wires connect the generator to the heart.
The pacemaker's generator sends the electrical pulses that correct or set your heart rhythm. A computer chip figures out what types of electrical pulses to send to the heart and when those pulses are needed. To do this, the computer chip uses the information it receives from the wires connected to the heart. It also may use information from sensors in the wires that detect your movement, blood temperature, breathing, or other factors that indicate your level of physical activity. That way, it can make your heart beat faster when you exercise.
The computer chip also records your heart's electrical activity and heart rhythms. Your doctor will use these recordings to set your pacemaker so it works better at making sure you have a normal heart rhythm. Your doctor can program the computer in the pacemaker without having to use needles or directly contacting the pacemaker.
The wires in your pacemaker send electrical pulses to and from your heart and the generator. Pacemakers have one to three wires that are each placed in different chambers of the heart.
The wires in a single-chamber pacemaker usually carry pulses between the right ventricle (the lower right chamber of your heart) and the generator.
The wires in a dual-chamber pacemaker carry pulses between the right atrium and the right ventricle and the generator. The pulses help coordinate the timing of these two chambers' contractions.
The wires in a triple-chamber pacemaker are used for heart muscle weakness and carry pulses between an atrium and both ventricles and the generator. The pulses help coordinate the timing of the two ventricles with each other.
Cross-Section of the Chest With a Pacemaker
The illustration shows a cross-section of the chest with a pacemaker. Figure A shows the location and general size of a double chamber, or double lead, pacemaker in the upper chest. The wires with electrodes are inserted into the right atrium and ventricle of the heart through a vein in the upper chest. Figure B shows the electrode electrically stimulating the heart muscle. Figure C shows the location and general size of a single chamber, or single lead, pacemaker in the upper chest. The wire with the electrode is inserted into the right ventricle of the heart through a vein in the upper chest.
Types of Pacemaker Programming
There are two main types of programming for pacemakers—demand pacing and rate-responsive pacing.
A demand pacemaker monitors your heart rhythm. It only electrically stimulates your heart if it's beating too slow or if it misses a beat.
A rate-responsive pacemaker will speed up or slow down your heart rate depending on how active you are. To do this, the rate-responsive pacemaker monitors your sinus node rate, breathing, blood temperature, or other factors to determine your activity level. Most people who need a pacemaker to continually set the pace of their heartbeat have rate-responsive pacemakers.
What To Expect During Pacemaker Surgery
Placement of a pacemaker requires minor surgery, which is usually done in a hospital or special heart treatment laboratory. You will be given medicine right before the surgery that will help you relax and may make you fall nearly asleep. Your doctor will give you a local anesthetic so you won't feel anything in the area where he or she puts the pacemaker.
First, your doctor will place a needle in a large vein, usually near the shoulder opposite your dominant hand. The doctor will then use the needle to thread the pacemaker wires into a vein and to the correct location in your heart.
An x-ray "movie" of the wires as they pass through your vein and into your heart will help your doctor place the wires. Once the wires are in place, your doctor will make a small cut into the skin of your chest or abdomen. He or she will then slip the pacemaker generator/battery box through the cut, place it just under your skin, and connect it to the wires that lead to your heart.
Once the pacemaker is in place, your doctor will sew up the cut. The entire surgery takes a few hours.
What To Expect After Pacemaker Surgery
Expect to stay in the hospital overnight so your heartbeat can be monitored and your doctor can make sure your pacemaker is working properly. You probably will have to arrange for a ride to and from the hospital because your doctor may not want you to drive yourself.
For a few days to weeks after surgery, you may have pain, swelling, or tenderness in the area where your pacemaker was placed. The pain is usually mild and often relieved by over-the-counter medicines. Consult with your doctor before taking any pain medicines.
Your doctor also may ask you to avoid any vigorous activities and heavy lifting for about a month. Most people return to normal activities within a few days of having pacemaker surgery.
What Are the Risks of Pacemaker Surgery?
Your chance of having any problems from pacemaker surgery is less than 5 percent. These problems may include:
- Swelling, bleeding, bruising, or infection in the area where the pacemaker was placed
- Blood vessel or nerve damage
- A collapsed lung
- A bad reaction to the medicine used to make you sleep during the procedure
- Infections that can become difficult to treat
How Will a Pacemaker Affect my Lifestyle?
Once you have a pacemaker, you have to avoid close or prolonged contact with electrical devices or devices that have strong magnetic fields. Devices for which close and prolonged exposure can interfere with a pacemaker include:
- Cell phones
- iPods
- Appliances, such as microwave ovens
- High-tension wires
- Metal detectors
- Industrial welders
- Electrical generators
These devices can disrupt the electrical signaling of your pacemaker and stop it from working properly. You may not be able to tell whether your pacemaker has been affected. How likely a device is to disrupt your pacemaker depends on how long you're exposed to it and how close it is to your pacemaker.
To be on the safe side, some experts recommend not putting your cell phone or iPod in a shirt pocket over your pacemaker (if they are turned on). You may want to hold the cell phone up to the ear that’s opposite the site where your pacemaker was implanted. If you strap your iPod to your arm while listening to it, put it on the arm farthest from your pacemaker.
You can still use household appliances, but avoid close and prolonged exposure, as it may interfere with your pacemaker.
You can walk through security system metal detectors at your normal pace. You also can be checked with a metal detector wand as long as it isn't held for too long over your pacemaker site. You should avoid sitting or standing close to a security system metal detector.
Stay at least 2 feet away from industrial welders or electrical generators.
You also need to avoid some medical procedures that can disrupt your pacemaker. These procedures include:
- Magnetic resonance imaging (also called MRI)
- Shock-wave lithotripsy to get rid of kidney stones
- Electrocauterization to stop bleeding during surgery
Let all of your doctors, dentists, and medical technicians know that you have a pacemaker. You also should notify airport screeners. Your doctor can give you a card that states what kind of pacemaker you have. Carry this card in your wallet.
Physical Activity
In most cases, having a pacemaker won't limit you from doing sports and exercise, including strenuous activities. You may need to avoid full-contact sports, such as football. Such contact could damage your pacemaker or shake loose the wires in your heart. Ask your doctor how much and what kinds of physical activity are safe for you.
Followup
Your doctor will want to check your pacemaker regularly. Over time, a pacemaker can stop working properly because:
- Its wires get dislodged or broken
- Its battery fails
- Your heart disease progresses
- Devices giving off strong electrical, magnetic, or radio waves have disrupted its electrical signaling
To check your pacemaker, your doctor may ask you to come in for an office visit several times a year. Some pacemaker functions can be checked remotely through a telephone call or a computer connection to the Internet. Your doctor also may ask you to have an EKG (electrocardiogram) to monitor changes in the electrical activity of your heart.
Battery Replacement
Pacemaker batteries last between 5 and 15 years, depending on how active the pacemaker is. Your doctor will replace the generator along with the battery before the battery begins to run down.
Replacement of the generator/battery is a less involved surgery than the original surgery to implant the pacemaker. The wires of your pacemaker also may need to be replaced eventually. Your doctor can tell you whether you need to replace your pacemaker or its wires.
Key Points
- A pacemaker is a small device that's placed under the skin of your chest or abdomen to help control irregular heartbeats. This device uses electrical pulses to prompt the heart to beat at a normal rate.
- Pacemakers are used to treat heart rhythms that are too slow, fast, or irregular. These abnormal heart rhythms are called arrhythmias.
- Pacemakers can relieve some symptoms related to arrhythmias, such as fatigue (tiredness) and fainting, and can help people who have arrhythmias resume a more active lifestyle.
- A pacemaker is similar to an implantable cardioverter defibrillator (ICD), but an ICD can use higher energy electrical pulses to treat certain dangerous arrhythmias. (To treat fast heart rhythms, a pacemaker is combined with an ICD in a single device.)
- Your doctor may recommend a pacemaker if aging, heart disease, or other factors make your heart beat too slow, too fast, or irregularly.
- Symptoms such as fainting, shortness of breath, and fatigue (tiredness) may be due to an irregular heartbeat that a pacemaker could correct. Your doctor will confirm whether you need a pacemaker based on your symptoms, any medicines you take, and test results.
- A pacemaker consists of a battery, a computerized generator, and wires. The generator sends the electrical pulses that correct or set your heart rhythm, and the wires carry pulses to and from various chambers of your heart and the generator.
- Pacemaker surgery is usually done in a hospital or special heart treatment laboratory. You will be given medicine to help you relax. The surgery takes just a few hours, but you will stay in the hospital overnight so your doctor can monitor your heart rhythm and make sure your pacemaker is working properly.
- Problems from pacemaker surgery are rare. Most people can return to normal activities within a few days.
- Your doctor may ask you to avoid any vigorous exercise or heavy lifting for a short period after your surgery. After you have fully recovered from surgery, discuss with your doctor how much and what kinds of physical activity are safe for you.
- Once you have a pacemaker, you have to avoid close or prolonged contact with electrical devices or devices that have strong magnetic fields. You also need to avoid certain medical procedures that can disrupt your pacemaker.
- Let all of your doctors, dentists, and medical technicians know that you have a pacemaker
- Have your pacemaker checked regularly. Some pacemaker functions can be checked remotely through a telephone call or a computer connection to the Internet. Your doctor may ask you to come to his or her office to check your pacemaker.
- Pacemaker batteries have to be replaced every 5 to 15 years, depending on how active your pacemaker is. The wires of your pacemaker also may need to be replaced eventually. Your doctor can tell you whether you need to replace your pacemaker or its wires.
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