Cardiac pacemaker

A cardiac pacemaker with its lead wires.

A cardiac pacemaker (KAR-dee-ak PAYS-may-ker) is an electronic medical device designed to regulate the heart's rhythm and rate. By delivering electrical impulses to the heart muscle, it aids the heart in maintaining a normal rhythm, especially when the heart's natural pacemaking capabilities are compromised. Also known as an artificial pacemaker or simply pacemaker, this device has revolutionized the treatment of certain cardiac arrhythmias.

Structure and Function

• Battery: The power source of the pacemaker, designed to last several years depending on usage and type.
• Pulse Generator: Produces the electrical impulses that stimulate the heart.
• Leads: Long, thin wires that connect the pulse generator to specific regions of the heart. They transmit the electrical impulses and also detect the heart's own electrical activity.

Diagram showing the placement of pacemaker leads within the heart.

Indications for Use

Cardiac pacemakers are typically recommended for patients who have:

• Bradycardia: An abnormally slow heart rate.
• Heart block: An interruption in the electrical pathways of the heart.
• Certain types of arrhythmias: Irregular heart rhythms that can be life-threatening or cause significant symptoms.

Implantation

The pacemaker implantation procedure is generally a minimally invasive surgery, often performed under local anesthesia. A small incision is made, usually in the chest area, through which the pacemaker is inserted and the leads are guided to the heart using fluoroscopic guidance. Once in place, the device is tested to ensure proper function, and the incision is closed.

Monitoring and Maintenance

Post-implantation, routine follow-up appointments are crucial:

• Device checks: To monitor battery life and ensure the pacemaker is functioning correctly.
• Lead assessments: To ensure the leads remain in the proper position and are effectively transmitting signals.
• Adjustments: The pacemaker settings might be adjusted depending on the patient's needs.

Patients are also educated on recognizing signs of potential complications and the importance of avoiding strong electromagnetic fields which might interfere with the device's function.

Advancements

Modern pacemakers have evolved to incorporate features like MRI compatibility, rate-responsive pacing (where the device adjusts the pacing rate based on the body's activity level), and dual-chamber pacing (which can pace both the atrium and ventricle of the heart).

See Also

• Defibrillator
• Cardiac arrhythmia
• Cardiac ablation
• Electrocardiogram (ECG)

References

• Pacemakers. American Heart Association. [1].
• Cardiac Pacemakers: From the Patient's Perspective. Circulation Journal. [2].