pacemaker

A pacemaker is a small electronic device that uses electrical pulses to regulate the heart rate and rhythm when the heart's natural pacing is too slow or irregular. It is commonly used to treat bradycardia and heart block and can be part of therapy for certain forms of heart failure.

A pacemaker consists of a pulse generator (battery and electronics) and one or more leads that connect to the heart. The device senses the heart's rhythm and delivers electrical impulses as needed. Modern pacemakers may pace the atrium, the ventricle, or both, and some provide rate-responsive pacing that adjusts to activity. Some specialized devices also provide cardiac resynchronization therapy (CRT) with three leads to coordinate the ventricles in select heart failure patients.

Permanent pacemakers are implanted under the skin near the collarbone, with the leads threaded through veins into the heart. Temporary systems may be used after surgery or during acute illness. Indications include symptomatic bradycardia, atrioventricular block, sick sinus syndrome, and, in some cases, tachyarrhythmias managed with pacing.

Battery life is typically 5 to 15 years, varying with pacing needs; generators are replaced when depleted. Follow-up involves periodic clinic visits and device checks, often with remote monitoring. Risks include infection, lead problems, and procedure-related complications. Most modern devices are MRI-compatible under appropriate conditions, allowing safe imaging when indicated with proper precautions.