What is the Difference Between a Defibrillator & a Pacemaker?

A cardiac defibrillator treats dangerously fast heart rhythms with a strong electric shock. A pacemaker generates much smaller impulses to prevent the heart from beating too slowly.

Features

• Both devices consist of a generator and leads. The generator is a small titanium case containing a control circuit and a lithium battery. One or more insulated wires, the leads, connect the generator to your heart.

Function

• The control circuit monitors your heart and generates impulses to correct your heart rhythm. A pacemaker responds to slow rhythms with small impulses, causing your heart to beat. A defibrillator, which often includes the pacemaker function, also responds to very fast rhythms by generating a large shock. This stops your heart and allows it to resume a normal rhythm.

Size

• Each generation of devices gets smaller. However, defibrillators are typically larger. As of 2010, they range from about two to two-and-a-half inches across, with a thickness of about 0.3 to 0.6 inches.

Effects

• Once accustomed to a pacemaker, you should not notice it, though you may feel better. A defibrillator shock, however, can be painful. Ideally, your cardiac medications should prevent the need for defibrillation.

Considerations

• Precautions are the same for both devices: avoid strong electromagnetic fields and physical impacts. Your doctor can tell you which device is right for you.