06/06/2025
What Is a ?
A pacemaker is a small, implantable electronic device that helps regulate the heartbeat.
The heart’s rhythm is controlled by a natural pacemaker called the sinus node, which sends electrical signals to the lower chambers of the heart through a pathway called the cardiac conduction system. Damage to this system can result in slow or unreliable heartbeats, which can occur gradually with age or be caused by medical conditions such as infection, inflammatory diseases, or blockages in the arteries of the heart.
Who Needs a Pacemaker?
Pacemakers are commonly used for people who have a heart rate that is too slow (bradycardia) or who have disorders that interfere with the heart’s normal electrical pathways.1 A pacemaker prevents slow heart rates that may cause shortness of breath, fatigue, lightheadedness, or even sudden death. In some patients, damage to the heart’s conduction system causes no symptoms at first but can lead to dangerous events like fainting or even sudden death.
For patients with or at risk of heart failure, a specialized pacemaker may be used to help coordinate the heart’s contractions. This can involve placing an extra lead to pace both sides of the heart or positioning a lead deeper in the heart’s conduction system to help prevent or reverse weakening of the heart muscle.
What Does a Pacemaker Do?
A pacemaker monitors the heart’s electrical signals and sends small, painless electrical impulses to make the heart contract when needed, maintaining a steady, reliable rhythm. A conventional pacemaker consists of a battery connected to leads (wires) that attach to the heart, allowing the device to both monitor and pace the heart.
How Are Pacemakers Implanted?
Implanting a conventional pacemaker involves a minor surgery, usually done under sedation. A small incision is made under the collarbone to place the battery under the skin. Leads are then threaded through a nearby vein into the heart under x-ray guidance and connected to the battery.
Recently, “leadless” pacemakers—small, capsule-sized devices—have been developed that are inserted into the heart after being passed through a vein in the groin. These pacemakers are a good option for people with blockages in their upper body veins or in those at higher risk of infection. However, compared with standard pacemakers, leadless pacemakers have more limited programming options, and when the battery runs low, leadless pacemakers need to be replaced or a second pacemaker needs to be placed.
Living With a Pacemaker
Most people with a pacemaker can live healthy, active lives after a few weeks of limited activity to prevent lead dislodgement after implantation. Individuals with modern pacemakers can undergo magnetic resonance imaging (MRI) but should avoid deepwater diving or arc welding. Regular checkups in a pacemaker clinic can ensure a pacemaker is working well. The pacemaker battery is typically replaced every 8 to 12 years with a minor surgical procedure in which the pacemaker generator containing the battery is replaced with a new device.