A system for detecting cardiac activity for a heart pacemaker

摘要

A cardiac event detecting system for an implantable heart stimulator intended to be connected to the heart of a patient through at least two unipolar electrode leads or at least one bipolar electrode lead having one eletrode pole in the atrium and one electrode pole in the ventricle for sensing heart signals comprises at least two signal channels for signals sensed between the two electrode poles and between one of the electrode poles and the stimulator capsule respectively. Each signal channel comprises signal processing means (12; C10, C6 ... C0.3, C0.2, C-0.2, C-0.3 ... C-6, C-10; 14). A decision logic means is provided for comparing the signals from the two signal channels with signal criteria for detecting the occurrence of a cardiac event. A/D-converting means (C10, C6 ... C0.3, C0.2, C-0.2, C-0.3 ... C-6, C-10) are provided for converting sampled values of said sensed heart signals into digital words for each signal channel. The decision logic is adapted for comparing the digital words and their differences with the criteria for determining the occurrence of a cardiac event.