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Pacemaker & ICD

What is a pacemaker?

A pacemaker is a device that is implanted in the chest and supplies electrical signals that the heart needs to maintain a normal heartbeat.

There are three parts to a pacemaker:

  1. The pulse generator produces the electrical signals. It is about the size of a matchbook, and contains a battery and electronic circuitry.
  2. The leads are small wires that carry the signal from the generator to the electrodes. Where your doctor decides to place the leads depends on your particular heart problem.
  3. The electrodes are located at the end of the leads and actually deliver the signal to the heart.

How does a pacemaker work?

The circuits of the pacemaker monitor your heart's rhythm and deliver an electrical signal when it detects that the heart is beating too slow, so that your heart keeps beating at a normal rate. Many newer pacemakers have a feature that allows for temporary faster pacing during exercise -- when your heart must beat faster to meet the increased demand for blood and oxygen.

The pacemaker's leads connect the generator to the part of the heart where the electrical impulse is delivered. There are two major types of pacemakers. Single chamber pacemakers have only one wire connecting the pacemaker to one chamber of the heart (either the right atrium or the right ventricle), and dual chamber pacemakers have wires connected to both the top and bottom chambers of the heart (the right atrium and the right ventricle). Your cardiologist will determine which type is needed. At the end of the wires are electrodes that actually deliver the electrical impulse to the heart.

Some newer devices are a combination of a biventricular pacemaker and an ICD in one unit for people with moderate to severe heart failure. In a normal heart, the right and left ventricles pump together, but if you have heart failure, they do not. The left ventricle then is not able to pump enough blood to the body. This can cause symptoms such as shortness of breath, cough, swelling in the ankles or legs, weight gain, increased urination, fatigue, or rapid or irregular heartbeat. The biventricular pacemaker part of the device treats the delay in heart ventricle contractions by keeping the right and left ventricles pumping together, while the ICD part helps prevent potentially fatal arrhythmias.

Who needs a pacemaker?

About 3 million people worldwide have pacemakers.4 In 2002, pacemakers were implanted in 199,000 people in the US (half were women).2 Most pacemakers are implanted to treat bradycardia (a dangerously slow heart rate). If the heart does not beat fast enough, the brain and body don't get the blood and oxygen necessary for them to function. Symptoms of bradycardia include:

  • Fainting
  • Dizziness
  • Lack of energy or fatigue
  • Shortness of breath

Some people do not experience any symptoms at all. Bradycardia often arises from problems with the heart's natural pacemaker, known as the sinoatrial node or sinus node. These problems can be a result of older age, heart disease, or heart medications. Less often, pacemakers are implanted in people with heart block, a condition in which the heart's normal electrical signal fails to reach the ventricles (the pumping chambers of the heart), causing a slow heart beat.

How well do women do after having a pacemaker implanted?

After getting a pacemaker implanted, women appear to live longer than men with pacemakers. In one study of about 6,500 people, women lived an average of 2 years longer than men despite being older than men when they had their pacemaker implanted.5 In another study of nearly 1,600 people over age 80, women were 30% less likely to die in the years following their pacemaker implantation than men.6

Can I just take medicine instead of getting a pacemaker?

In most cases, no, because the slow rhythm is related to underlying problems with the heart's pacemaker cells or conducting system. In these cases, medications are not effective. If you are suffering from many of the symptoms of bradycardia, the best course of treatment is to have a pacemaker implanted. Some people, however, may have pacemakers implanted and also take medication.

Filed in Treatment & Recovery > Pacemaker & ICD


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