Pacemaker Indications

Excerpt

Pacemakers are electronic devices that stimulate the heart with electrical impulses to maintain or restore a normal heartbeat. In 1952, Zoll described an effective means of supporting the patients with intrinsic cardiac pacemaker activity and/or conducting tissue by an artificial, electric, external pacemaker. The pacing of the heart was accomplished by subcutaneous electrodes but could be maintained only for a short period. In 1957, complete heart block was treated using electrodes directly attached to the heart. These early observations instilled the idea that cardiac electrical failure can be controlled. It ultimately led to the development of totally implantable pacemaker by Chardack, Gage, and Greatbatch. Since then, there have been several advancements in the pacemakers, and the modern-day permanent pacemaker is subcutaneously placed device.There are 3 types of artificial pacemakers:

1. Implantable pulse generators with endocardial or myocardial electrodes

2. External, miniaturized, patient portable, battery-powered, pulse generators with exteriorized electrodes for temporary transvenous endocardial or transthoracic myocardial pacing

3. Console battery or AC-powered cardioverters or monitors with high-current external transcutaneous or low-current endocardial or myocardial circuits for temporary pacing in asynchronous or demand modes, with manual or triggered initiation of pacing

All cardiac pacemakers consist of 2 components: a pulse generator which provides the electrical impulse for myocardial stimulation and 1 or more electrodes or leads which deliver the electrical impulse from the generator to the myocardium. This discussion focuses on the indications of pacemaker placement.