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How does a pacemaker work?

A pacemaker is a small device that is implanted in the chest (right or left side) and helps control the heartbeat. It is used to prevent the heart from beating too slowly and its implantation requires a surgical procedure.

Depending on the heart condition, one of the following types of pacemakers will be implanted:

  • Single chamber pacemaker: This type of pacemaker usually carries electrical impulses to the right ventricle of the heart.
  • Dual chamber pacemaker: This type of pacemaker carries electrical impulses to the right ventricle and right atrium of the heart to help control the timing of contractions between the two chambers.
  • Biventricular pacemaker: Biventricular pacemaker is for people who have heart failure and heartbeat problems. This type of pacemaker stimulates both lower chambers of the heart (right and left ventricles) so that the heart beats more efficiently.

Why is it implanted?

A pacemaker is implanted to help control the heartbeat. Your doctor may recommend a temporary pacemaker when you have a slow heartbeat (bradycardia) after a heart attack, surgery, or drug overdose, but otherwise your heartbeat is expected to recover. A pacemaker may be permanently implanted to correct chronic slow or irregular heartbeats or to help treat heart failure.

How does the heart beat?

The heart is a muscular, fist-sized pump with four chambers, two on the left and two on the right. The upper chambers (right and left atria) and lower chambers (right and left ventricles) work with the heart's electrical system to keep the heart beating at a proper rate, usually 60 to 100 beats per minute for adults at rest.

The heart's electrical system controls the heartbeat, starting with a group of cells at the top of the heart (sinus node) and extending to the bottom so that it contracts and pumps blood. Aging, damage to the heart muscle from a heart attack, some medications, and certain genetic conditions can cause an abnormal heart rhythm.

What does a pacemaker do?

Pacemakers work only when needed. If the heartbeat is too slow (bradycardia), the pacemaker sends electrical signals to the heart to correct the heartbeat.

Some newer pacemakers also have sensors that detect body movement or breathing rate, which tells them to increase the heart rate during exercise as needed.

A pacemaker consists of two parts:

  • pulse generator. This small metal container houses a battery and the electrical circuitry that controls the rate of electrical impulses sent to the heart.
  • Wires (electrodes). One to three flexible insulated wires are placed in one or more chambers of the heart, and these send electrical impulses to match the heart rate. However, some newer pacemakers do not require leads. These devices, called wireless pacemakers, are implanted directly into the heart muscle.


Complications related to surgery to implant the pacemaker or having a pacemaker are rare, but may include the following:

  • Infection near the site of the heart where the device is implanted
  • Swelling, bruising, or bleeding at the pacemaker site, especially if you take blood thinners
  • Blood clots (thromboembolism) near the site of the pacemaker
  • Damage to blood vessels or nerves near the pacemaker
  • Lung collapse (pneumothorax)
  • Blood in the space between the lung and the chest wall (hemothorax)
  • Movement (displacement) of the device or leads

How do you prepare?

Before your doctor decides if you need a pacemaker, you'll have several tests to find the cause of your irregular heart rhythm. Tests done before a pacemaker is placed may include:

  • Electrocardiogram. This quick and painless test measures the electrical activity of the heart. Adhesive patches (electrodes) are placed on the chest and sometimes on the arms and legs. They have wires that connect the electrodes to a computer that displays the results. A electrocardiogram It can show if your heart is beating too fast, too slow, or not at all.
  • Holter monitoring. A Holter monitor is a small, portable device that keeps track of your heart rhythm. Your doctor may ask you to wear a Holter monitor for 1 to 2 days. During that time, the device records every heartbeat. Holter monitoring is especially helpful in diagnosing heartbeat-related problems that occur at unpredictable times. Some personal devices, such as smartwatches, offer electrocardiogram monitoring. Ask your doctor if this is an option for you.
  • Echocardiogram. This noninvasive test uses sound waves to produce images of the size, structure, and motion of the heart.
  • Stress test. Some heart problems appear only during exercise. For a stress test, an electrocardiogram is taken before and immediately after you walk on a treadmill or ride a stationary bike. Sometimes a stress test is done along with an echocardiogram or nuclear medicine imaging.

Before the procedure

You will probably be awake during the surgery to implant the pacemaker, which usually takes a few hours. The specialist will insert an IV into your forearm or hand and give you a medicine called a sedative, which will help you relax. The chest is cleaned with a special soap.

Most pacemaker implants are done using local anesthesia to numb the area of ​​the incisions. However, the amount of sedation needed for the procedure depends on what conditions you have. You may be fully awake or lightly sedated, or given general anesthesia (fully asleep).

during the procedure

One or more wires are inserted into a major vein below or near the clavicle and guided to the heart using X-ray imaging. One end of each wire is fixed in place in the heart, while the other end is connected to the pulse generator, which is usually implanted under the skin near the clavicle.

The leadless pacemaker is smaller and generally requires less invasive surgery to implant. The pulse generator and other parts of the pacemaker are contained within a single capsule. The doctor inserts a flexible sheath (catheter) into a vein in the groin and then guides the unique component of the pacemaker through the catheter to the indicated position in the heart.

After the procedure

You will probably stay in the hospital for a day after you have a pacemaker implanted. The pacemaker will be programmed to match your heart rate needs. You will need to arrange for someone to drive you home from the hospital.

Your doctor may recommend that you avoid strenuous exercise or heavy lifting for about a month. Avoid putting pressure on the area where the pacemaker was implanted. If you feel pain in that area, ask your doctor if you can take over-the-counter medications such as acetaminophen (Tylenol or others) or ibuprofen (Advil, Motrin IB, or others).

special precautions

It is unlikely that your pacemaker will stop working properly due to electrical interference. Despite that, you should take some precautions:

  • Mobile phones. It is safe to talk on a cell phone, but you must keep it at least 6 inches (15 centimeters) away from your pacemaker. Don't keep your phone in your shirt pocket. When you talk on the phone, hold it to the ear opposite the side where your pacemaker was implanted.
  • Security systems. Going through a metal detector at the airport will not interfere with your pacemaker, although the metal inside your pacemaker could set off the alarm. However, avoid standing close to or leaning against a metal detection system.

    To avoid potential problems, carry an identification card that says you have a pacemaker.

  • Medical equipments. Make sure all your doctors and dentists know that you have a pacemaker. Certain medical procedures, such as MRIs, CT scans , radiation therapy for cancer, electrocautery to control bleeding during surgery, and shock wave lithotripsy to break up large kidney stones or gallstones may interfere with the pacemaker.
  • Power generating equipment. Stay at least 2 feet (61 cm) from welding equipment, high voltage transformers, or motor generator systems. If you work around such equipment, ask your doctor to arrange a test at your workplace to determine if the equipment affects your pacemaker.

Devices that are unlikely to interfere with your pacemaker include microwave ovens, televisions and remote controls, radios, toasters, electric blankets, electric shavers, and electric drills.


A pacemaker should improve symptoms caused by a slow heartbeat, such as fatigue, lightheadedness, and fainting. Since most of today's pacemakers automatically adjust your heart rate according to your level of physical activity, they can allow you to return to a more active lifestyle.

Your doctor should check your pacemaker every 3 to 6 months. Tell your doctor if you gain weight, if your legs or ankles swell, or if you faint or feel dizzy.

Your doctor can check most pacemakers remotely, which means you don't have to come to the office. The pacemaker sends information to the doctor, such as heart rate and rhythm, pacemaker function, and battery life.

Your pacemaker battery should last between 5 and 15 years. When the battery dies, you will have to have surgery to replace it. The procedure to change the pacemaker battery is usually faster and requires less recovery time than the procedure to implant the pacemaker.

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