Adaptive waveform appraisal in an implantable cardiac system

摘要

Methods and implantable devices for cardiac signal analysis. The methods and devices make use of waveform appraisal techniques to distinguish event detections into categories for suspect events and waveform appraisal passing events. When adjustments are made to the data entering analysis for waveform appraisal, the waveform appraisal thresholds applied are modified as well. For example, when the data analysis window for waveform appraisal changes in length, a waveform appraisal threshold is modified. Other changes, including changes in sensing characteristics with which waveform appraisal operates may also result in changes to the waveform appraisal threshold including changes in gain, sensing vector, activation of other devices, implantee posture and other examples which are explained.

主权项

1. An implantable device (ID) comprising operational circuitry and a plurality of electrodes electrically coupled to the operational circuitry to allow observation of electrical activity by the operational circuitry when the ID is implanted in a patient, wherein the operational circuitry is configured to perform a method of detecting cardiac signals, comprising:
sensing electrical activity using the electrodes; detecting a detected event in the electrical activity; analyzing the detected event by defining an analysis window having an analysis window duration, identifying characteristic features of the electrical activity sensed during the analysis window, and counting the characteristic features that occur during the analysis window to generate a characteristic feature count for the detected event; and comparing the characteristic feature count to a predefined threshold and either rejecting the detected event as suspect or accepting the detected event as likely being of cardiac origin; wherein the operational circuitry is configured to modify the analysis window duration and the predefined threshold to maintain a desired relationship therebetween.