Systolic time intervals as a control of rate adaptive pacing

The pre-ejection period (PEP) is shown to be a suitable parameter for physiologic adaptation of a pacing rate. Technical details of an implantable multiprogrammable pacemaker using PEP are described. The control algorithm, overall system, PEP sensing circuits, and pulse generator circuits are described. Results based on clinical studies are presented. The clinical data show the feasibility of using a unipolar impedance measurement to detect PEP. The reliability of the principle, its simplicity, and the advantage of using standard pacemaker electrodes for stimulation and sensing of the cardiovascular control parameter is demonstrated