Implantable pacemakers for cardiac tachyarrhythmias.

The vast horizons opened by the newer knowledge gained from specialized electrophysiologic studies have led to the increasing use of implanted pacemakers for the management of a variety of tachyarrhythmias which are either drug-resistant or better controlled electrically. The ideal pacemaker should be custom-made, i.e., fit to the (predetermined) patient's needs, and should be self-activated. In addition, external programmability of pacing rates and modes is a very desirable feature.