[Method for the direct comparison of the frequency behavior in QT- and activity-controlled pacemaker systems].

A non-invasive method of testing the suitability of an activity-controlled pacemaker system in patients with VVT-programmable systems is presented. The QT-time controlled TX-pacemaker of a 36-year-old patient was programmed into the VVT-mode. Then the activity-controlled pacemaker (Activitrax) was fixed epicutaneously above the pectoral muscles and two stimulation electrodes were applied above the implanted pacer and the tip of the implanted probe. Thus the external could be made to trigger the implanted system. The frequency profile was recorded with identical loads with QT and/or activity control. For both the frequency-adapted pacemaker systems, the direct comparison yields characteristic frequency profiles: a quick frequency increase and decrease of both Activitrax and load, but a delayed frequency profile of the QT-controlled pacer. Different frequency maxima are rendered by the two pacemakers as a function of the load.