Faulty electrical signaling in the heart cause an arrhythmia. A pacemaker uses low-energy electrical pulses to correct faulty electrical signaling. Cardiologists implant pacemakers because they can:

• Speed up a slow heartbeat
• Help end an abnormal and fast rhythm with an implantable cardioverter defibrillator/ICD
• Make sure the ventricles contract normally if the atria are quivering instead of beating in a normal rhythm (a condition called atrial fibrillation)
• Coordinate the electrical signaling between the upper and lower chambers of the heart
• Coordinate the electrical signaling between the ventricles (cardiac resynchronization therapy used in heart failure)

Pacemakers also can monitor and record your heart's electrical activity and the rhythm of your heartbeat. Newer pacemakers can monitor your blood temperature, breathing rate, and other factors and adjust your heart rate to changes in your activity.

Cross-Section of the Chest With a Pacemaker

The illustration shows a cross-section of the chest with a pacemaker. Figure A shows the location and general size of a double chamber, or double lead, pacemaker in the upper chest. The wires with electrodes are inserted into the right atrium and ventricle of the heart through a vein in the upper chest. Figure B shows the electrode electrically stimulating the heart muscle. Figure C shows the location and general size of a single chamber, or single lead, pacemaker in the upper chest. The wire with the electrode is inserted into the right ventricle of the heart through a vein in the upper chest.

What Is a Pacemaker?

A pacemaker is a small device that cardiologists place under the skin of your chest or abdomen to help control abnormal heart rhythms. This device uses electrical pulses to prompt the heart to beat at a normal rate.

Pacemakers are used to treat heart rhythms that are too slow or irregular. These abnormal heart rhythms are called arrhythmias. Pacemakers can relieve some symptoms related to arrhythmias, such as fatigue and fainting. A pacemaker can help a person who has an abnormal heart rhythm resume a more active lifestyle.

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