Systems and methods for sensing vector selection in an implantable medical device

Inventors

Sanghera, Rick • Allavatam, Venugopal

Assignees

Cameron Health Inc

Abstract

Methods and devices for sensing vector analysis in an implantable cardiac stimulus system. In an illustrative example, a first sensing vector is analyzed to determine whether it is suitable, within given threshold conditions, for use in cardiac event detection and analysis. If so, the first vector may be selected for detection and analysis. Otherwise, one or more additional vectors are analyzed. A detailed example illustrates methods for analyzing sensing vectors by the use of a scoring system. Devices adapted to perform these methods are also discussed, including implantable medical devices adapted to perform these methods, and systems comprising implantable medical devices and programmers adapted to communicate with implantable medical devices, the systems also being adapted to perform these methods. Another example includes a programmer configured to perform these methods including certain steps of directing operation of an associated implanted or implantable medical device.

Core Innovation

The invention relates to an implantable stimulus device having an implantable lead and operational circuitry within a housing, where the operational circuitry is coupled to a plurality of electrodes for sensing cardiac activity. The plurality of electrodes includes at least one electrode on the housing and at least one electrode on the lead, and the operational circuitry receives a signal from the electrodes to sense a plurality of detected events separated by intervals. The operational circuitry analyzes consecutive intervals defined between pairs of detected events to identify patterns in the temporal structure of the detected events.

After analyzing consecutive intervals, the operational circuitry determines that at least two consecutive intervals are equal within a predefined margin and that the at least two equal consecutive intervals are each shorter than a predefined duration. When these conditions are met, the operational circuitry marks whichever of the two detected events occurring at the start of each of the consecutive intervals is of lesser amplitude as noise and the other of the two detected events as QRS. The sensing of detected events is performed by comparing a sensing threshold set to a selected amplitude to the received signal, observing crossing to declare a detected event, applying a refractory period, and again comparing after the refractory period to sense a subsequent detected event.

In related embodiments, the QRS is used to identify and select a default sensing vector for the medical device, and the default sensing vector is then used to sense cardiac activity. The document further indicates that vector selection is grounded in analyzing detected QRS events, including an amplitude factor, and, in some embodiments, analyzing detected noise events, including a noise factor. Vectoring may be performed by the implantable device and/or an external programmer with telemetry, including optional operator input related to how selected sensing vector criteria are determined.

Claims Coverage

The document includes two independent claims directed to an implantable medical device for detecting and classifying events based on equal consecutive intervals and amplitude comparison, and a corresponding method that additionally uses QRS to select a default sensing vector for sensing cardiac activity. Across the independent claims, the core inventive features include interval-based QRS/noise classification and threshold-crossing event detection with a refractory period, with vector selection as a further inventive aspect in the method claim.

Collectively, the independent claims cover event sensing using threshold crossing with a refractory period, classification of events into noise versus QRS based on equal consecutive intervals within a margin and shorter than a predefined duration with an amplitude comparison, and, in the method, using QRS to identify and select a default sensing vector for subsequent sensing of cardiac activity.

Stated Advantages

Documented Applications

No documented applications found