Introduction of an automatic QT interval driven rate responsive pacemaker.

QT driven rate responsive pacemakers have been implanted since 1981. The more than 6 years experience and additional knowledge gained during several clinical studies have culminated in the design of an automatic rate responsive pacemaker. The adjustment of the rate responsive function to each individual patient is carried out automatically by the pacemaker, which therefore performs several measurements both at rest and during exercise. The results of these measurements are used to adapt the rate responsive parameters in order to optimize the rate response, even under changing circumstances.