Advanced cardiovascular monitoring system with personalized st-segment thresholds

Inventors

Fischell, David R. • John, Michael Sasha • Keenan, David • Johnson, Steve • Turi, Gregg

Assignees

Avertix Medical Inc

Abstract

A device for detecting acute coronary syndrome (ACS) events, arrythmias, heart rate abnormalities, medication problems such as non-compliance or ineffective amount or type of medication, and demand/supply related cardiac ischemia is disclosed. The device may have both implanted and external components and can communicate with other user devices such as smartphones and smartwatches for monitoring and alerting in response to detected medically relevant events or states of a patient. The processor is configured to provide event detection based upon various criteria including what is found to be statistically abnormal for a patient or what has been defined by a doctor to be abnormal. A patient's cardiovascular condition can be tracked over time using histogram, trend, and summary information related to heart rate and/or cardiac features such as those measured from the S-T segment of heartbeats. Heartbeats that are elevated but which are below what is defined as high, are used to provide medically relevant detections.

Core Innovation

The invention provides an actuating alarm technique responsive to detection of excessive ST shift from a heart signal of a patient. It measures, for each beat within a data collection time period, an ST deviation defined as an ST segment average voltage minus a PQ segment average voltage within each beat derived from a PQRST representation of the heart signal, and creates and stores at least one histogram comprising bins associated with ST deviation ranges, where each bin contains a running count of beats whose ST deviation falls within that bin during the data collection time period.

The invention derives excessive ST deviation detection thresholds by operating on the histogram distribution in a positive and negative manner. It initially independently calculates either a positive or negative excessive ST deviation threshold in the histogram, and then sequentially calculates the other excessive deviation threshold, with related system embodiments computing positive and negative standard deviation by creating symmetric distributions through mirroring positive and negative ST deviation values about a central value selected from a mean, a median, and a zero ST deviation value.

Excessive ST shift detection thresholds are then normalized to a baseline heart signal amplitude captured during the data collection time period, and the patient alerting mechanism is activated when a multiplicity of beats includes an ST shift that exceeds at least one of the positive or negative excessive ST shift detection thresholds. The baseline normalization is described as being computed from an average heart signal amplitude captured during the data collection time period.

Claims Coverage

The document contains three independent claims. Collectively, they define per-beat ST deviation computation from PQRST, histogram storage of ST deviation distributions over a data collection time period, separate positive and negative threshold derivation, mirrored symmetric distributions, and patient alert activation when an ST shift exceeds the derived thresholds.

Across the independent claims, the core coverage centers on computing per-beat ST deviation from a PQRST representation, storing ST deviation distributions in histogram bins over a data collection time period, deriving separate positive and negative excessive ST deviation and excessive ST shift detection thresholds using positive and negative processing and mirrored symmetric distributions, and activating a patient alerting mechanism when sensed ST shift exceeds the derived thresholds.

Stated Advantages

Documented Applications