System for detecting cardiac ischemia and irregular heart rhythms

• US 9,468,383 B2
• Filed: 06/25/2015
• Issued: 10/18/2016
• Est. Priority Date: 09/20/2002
• Status: Expired due to Fees

• Current Assignee: Angel Medical Systems, Inc.
• Original Assignee: Angel Medical Systems, Inc.
• Inventors: Fischell, David R., Fischell, Tim A., Harwood, Jonathan, Fischell, Robert E.
• Primary Examiner(s): EVANISKO, GEORGE ROBERT
• Application Number:
  US14/749,873
• Publication Number:
  US 20150289774A1
• Time in Patent Office: 481 Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2560/0209 adapted for power saving
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/02455 provided with high/low alarm devices
• CPC Class Codes: A61B 5/287 Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/352 Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
• CPC Class Codes: A61B 5/364 Detecting abnormal ECG interval, e.g. extrasystoles, ectopic heartbeats
• CPC Class Codes: A61B 5/366 Detecting abnormal QRS complex, e.g. widening
• CPC Class Codes: A61B 5/746 Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms alarms per se G08B
• CPC Class Codes: A61B 5/7465 Arrangements for interactive communication between patient and care services, e.g. by using a telephone network telemetry of measured physiological signal A61B5/0002

Abstract

A system for detecting acute ischemia includes at least two sensors configured for obtaining electrical signals from a patient'"'"'s heart, analog-to-digital converter circuitry for digitizing the signal to produce data segments, and a processor configured to analyze data segments to determine if they represent an abnormal heart rhythm. Certain types of abnormal rhythm segments are also checked for acute ischemia. If enough of the abnormal heart rhythm segments manifest acute ischemia, a first type of alarm event is generated. If persistent abnormal heart rhythm segments do not manifest acute ischemia, a second type of alarm event is generated.

Claims

1. A system for detecting a cardiac event in a human patient the system including:

(a) at least two sensors configured for obtaining an electrical signal from the patient'"'"'s heart,

(b) analog-to-digital converter circuitry for digitizing the signal to produce data segments having a time duration between 3 and 30 seconds;

(c) a implantable processor configured to;

(i) process the data segments to identify cardiac activity related to each heart beat, each beat being a sub-segment of the data segment having a measurable R-R interval from the preceding beat;

(ii) compute the R-R intervals of beats in each of the data segments, thereby generating a plurality of R-R intervals;

(iii) based upon the plurality of R-R intervals, categorize the rate of each of the data segments;

in each categorized data segment, determine between the segment having ST deviations above a predetermined threshold and data segments having ST deviations below a predetermined threshold;

(iv) perform ischemia detection on at least one of the data segments with the ST deviation above said predetermined threshold;

(v) based at least on the categorized rate and on the ischemia detection performed on one of the data segments with the ST deviation above said predetermined threshold, determine between ischemia being present and ischemia not being present;

(vi) operative upon determining that ischemia is present for a predetermined number of beats within the data segment, generate a first alarm event and transmit said first alarm event to an external receiver for notification of said first alarm event;

(vii) operative upon determining that ischemia is not present, generating a second different alarm event upon determining if a number of further data segments are segments with the ST deviation above said predetermined threshold for a predetermined number of beats within at least one of the further data segments.

2. The system of claim 1 wherein data segments with the ST deviation include low heart rate segments.

3. The system of claim 2 wherein data segments with the ST deviation include high heart rate segments.

4. The system of claim 3 wherein further data segments that are elevated after a detection of low heart rate data segments are checked for ischemia, but high heart rate data segments are not checked for ischemia.

5. The system of claim 1 wherein data segments with the ST deviation include unsteady heart rate segments.

6. The system of claim 1 wherein the sensors comprise electrodes.

7. The system of claim 6 wherein at least one of the electrodes is adapted for implantation within a heart.