How Does a Pacemaker Work? (And Other Common Questions)

Did you know that electricity drives every beat of your heart? A bundle of nerves at the heart's top -- called the sinus (or sinoatrial) node -- is an electrical generator. Nerves, functioning as wires, transmit messages to the lower chambers of your heart, telling it when to contract. For people with heart problems, these signals sometimes go awry and alter the heart's rhythm. A computerized electrical device, called a pacemaker, can control certain types of abnormal heart rhythm.

Who Needs One?

Pacemakers are used for a variety of purposes, but most treat a condition called bradycardia -- a slow heartbeat. People with slow heart rates tire easily, become dizzy, and are even susceptible to syncope (or fainting); pacemakers treat this condition by speeding the heart's rate back to normal. They also may help with other rhythm issues and can improve coordination among the different chambers of the heart. Let's take a look at some other common reasons for using the device:

• Pacemakers balance out atrial fibrillation, which is a type of irregular heart rhythm. While the pacemaker does not treat the atrial fibrillation per se, it prevents long pauses in the heart rate, which is common in patients with atrial fibrillation. Medications or specialized procedures can treat the atrial fibrillation directly.
  
• Heart failure sometimes responds to a specialized pacemaker, called a cardiac resynchronization or biventricular pacemaker.
• Pacemakers can correct a sick sinus node that's transmitting signals improperly.
• Some heart transplant patients need them.
• People with certain congenital heart conditions cannot maintain proper heart rhythm without pacemakers.
• Temporary pacemakers are used in emergencies and for people hospitalized by a heart attack or recovering from heart surgery.

How Do Pacemakers Work?

Surgically implanted under the skin near the right or left collarbone, pacemakers consist of a generator, battery, and anywhere from one to three small wires. Electrodes at the end of the wires attach to specific areas of the heart and send data to the generator's tiny computer. It then transmits programmed signals that, among other things, tell the lower chambers of the heart when to beat. Batteries last anywhere from 5 to 12 years and require minor surgery to replace. Physicians can interpret data sent by the device remotely and make needed changes using a programmer in their office. Demand pacemakers are used for slow or missed heartbeats, while rate-responsive ones adjust the heart rate based on a person's activity.

How Will a Pacemaker Affect My Daily Life?

Getting a pacemaker implanted involves minor surgery and sometimes an overnight stay in the hospital. The surgery site requires monitoring for signs of infection, but some mild pain and swelling is normal. You can usually return to your normal daily routine in less than a week but usually must avoid more strenuous activity for a month or longer. There may also be temporary restrictions on driving, depending on the preference of your cardiologist and the reason that the pacemaker was needed.

Certain situations might affect pacemakers' functions. For example, with many pacemakers, cellphones should not be kept in the breast pocket on the same side as the pacemaker, and cellphone conversations are safer using the ear on the opposite side. There may be restrictions around high-tension electrical wires, metal detectors, and electrical generators. Although metal-detection equipment will not damage the device, you should still notify airport security that you have it. Some medical procedures, such as MRIs, disrupt certain pacemakers.

Your doctor will periodically check the device for battery status, as well as to ensure no wires are broken and the device is functioning properly. The doctor may need to make adjustments, most of which can be done non-invasively with a programmer in the office. Surgery to replace the battery, generator, or wires is often less involved than the original implantation.

Technological innovations such as pacemakers not only prolong life, but they also improve quality of life by restoring the heart's electrical messaging system. With this data, your doctor can then make adjustments that preserve your heart health.

Bottom line: If you're experiencing heart problems, be sure to speak with your doctor about whether a pacemaker is an option that might help you.