Abstract: Apparatus for analyzing ECG signals from a patient in the form of a data stream comprises a data stream monitor to locate for each heart beat a trigger point (26,37,25) having a constant temporal displacement with respect to the location of a portion of the ECG signal (31-34) which may include micropotentials. A processor (15) determines which are acceptable beats and, where a heart beat is acceptable, generates and stores an average from successive portions. The resolution at which the average is stored is such that micropotentials present are detectable. The processor is adapted to store a set of averages generated during a corresponding number of time intervals.

Abstract: An ambulatory monitor for monitoring the action of a pacemaker and the cardiac response of a patient fitted with a pacemaker. The monitor comprises a detection electrode coupled in use to the patient for detecting pacemaker pulses and cardiac responses; an analyser connected to the detection electrode fora) analysing the relationship between the detected pacemaker impulses and cardiac responses,b) analysing the shape and timing of the cardiac responses, andc) generating corresponding data signals; and a recorder for recording the data signals.