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Heart Disease Health Center

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Heart Disease and Pacemakers

The normal, healthy heart has its own pacemaker that regulates the rate at which the heart beats.

However, some hearts don't beat regularly. Often, a pacemaker device can correct the problem. A pacemaker is a small device that sends electrical impulses to the heart muscle to maintain a suitable heart rate and rhythm. A pacemaker may also be used to treat fainting spells (syncope), congestive heart failure, and, rarely, hypertrophic cardiomyopathy.

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It is implanted just under the skin of the chest during minor surgery.

The pacemaker has two parts: the leads and a pulse generator. The pulse generator houses the battery and a tiny computer, and resides just under the skin of the chest. The leads are wires that are threaded through the veins into the heart and implanted into the heart muscle. They send impulses from the pulse generator to the heart muscle, as well as sense the heart's electrical activity.

Each impulse causes the heart to contract. The pacemaker may have one to three leads, depending on the type of pacemaker needed to treat your heart problem.

There are different types of pacemakers:

  • Single chamber pacemakers use one lead in the upper chambers (atria) or lower chambers (ventricles) of the heart.
  • Dual chamber pacemakers use one lead in the atria and one lead in the ventricles of your heart.
  • Biventricular pacemaker uses three leads: one placed in the right atrium, one placed in the right ventricle, and one placed near the left ventricle.

Your doctor will decide what type of pacemaker you need based on your heart condition.

The doctor programs the minimum heart rate. When your heart rate drops below that set rate, your pacemaker generates (fires) an electrical impulse that passes through the lead to the heart muscle. This causes the heart muscle to contract, creating a heartbeat.

Pacemakers are usually used to treat the following:

  • Bradyarrythmias, slow heart rhythms that may arise from disease in the heart's electrical conduction system (such as the SA node, AV node or HIS-Purkinje system).
  • Heart failure. This device is called cardiac resynchronization therapy (CRT) or biventricular pacing.

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