A variable rate pacemaker responsive to patient exercise senses physical activity of the patient by motion detection and generates a corresponding electrical signal. The pacemaker circuitry detects maximum and minimum values of the amplitude of the electrical signal in equal intervals of time. These...http://www.google.de/patents/US5031614?utm_source=gb-gplus-sharePatent US5031614 - Pacemaker rate control using amplitude and frequency of activity signal
