Method and apparatus for obtaining heartbeat measurements from a ECG waveform

• US 5,682,900 A
• Filed: 11/29/1995
• Issued: 11/04/1997
• Est. Priority Date: 11/29/1995
• Status: Expired due to Fees

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Arand, Patricia A., Post, William L.
• Primary Examiner(s): Getzow, Scott M.
• Application Number:
  US08/564,774
• Time in Patent Office: 706 Days
• Field of Search: 128/704, 128/703, 128/708, 128/702, 364/413.06
• US Class Current: 600/517
• CPC Class Codes: A61B 5/0245 by using sensing means generating electric signals, i.e. ECG signals
• CPC Class Codes: A61B 5/35 by template matching
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems

Abstract

A method and apparatus for obtaining heartbeat measurements obtains ECG data from a plurality of ECG waveforms, which are in turn obtained from signals received from a plurality of ECG electrodes. QRS detection logic detects heartbeats in the ECG data. Classification logic classifies heartbeats into categories based on shape and/or timing. Alignment logic aligns the heartbeats. Representative heartbeat creation logic creates a representative heartbeat from the aligned heartbeats. Measurement logic measures various aspects of the representative heartbeat. This logic analyzes the ECG waveforms to determine an earliest QRS onset and latest QRS offset, and uses these values to perform a variety of measurements. This results in robust measurements even in very noisy environments. The representative heartbeat is displayed, either alone or with heart rate and/or other measurement information, to the cardiologist or medical professional for diagnosis of the condition of the patient'"'"'s heart, such as a diagnosis of coronary artery disease, based on finding a depressed ST segment in the representative heartbeat of a patient undergoing a stress or exercise test.

Claims

1. A method of obtaining heartbeat measurements from an ECG waveform, said method comprising the steps of:

detecting a plurality of heartbeats in said ECG waveform;

classifying said plurality of heartbeats as dominant heartbeats and non-dominant heartbeats;

aligning said dominant heartbeats to create aligned dominant heartbeats;

creating a representative heartbeat from said plurality of aligned dominant heartbeats;

obtaining measurements for said representative heartbeat, further comprising the steps of;

obtaining a plurality of representative heartbeats corresponding to a plurality of ECG waveforms;

measuring an earliest QRS onset, responsive to said obtaining step;

measuring a latest QRS offset, responsive to said obtaining step;

for said representative heartbeat, determining a maximum R wave amplitude measurement between said earliest QRS onset and said latest QRS offset;

for said representative heartbeat, determining an average ST level measurement; and

for said representative heartbeat, determining an ST slope measurement by using a best line fit between the latest QRS offset and an ST measurement point of said representative heartbeat.

2. The method of claim 1, further comprising the step of:

for said representative heartbeat, determining an ST integral measurement by computing the sum of the negative area between said latest QRS offset and said ST measurement point of said representative heartbeat.

3. The method of claim 2, further comprising the steps of:

determining a level of confidence of said ST integral measurement; and

displaying an indication of said level of confidence.

4. The method of claim 1, further comprising the steps of:

determining a level of confidence of said ST slope measurement; and

displaying an indication of said level of confidence.

5. A method of obtaining heartbeat measurements from an ECG waveform, said method comprising the steps of:

detecting a plurality of heartbeats in said ECG waveform;

classifying said plurality of heartbeats as dominant heartbeats and non-dominant heartbeats;

aligning said dominant heartbeats to create aligned dominant heartbeats;

creating a representative heartbeat from said plurality of aligned dominant heartbeats;

obtaining measurements for said representative heartbeat, further comprising the steps of;

obtaining a plurality of representative heartbeats corresponding to a plurality of ECG waveforms;

measuring an earliest QRS onset, responsive to said obtaining step;

measuring a latest QRS offset, responsive to said obtaining step; and

for said representative heartbeat, determining a maximum R wave amplitude measurement between said earliest QRS onset and said latest QRS offset;

determining a level of confidence of said maximum R wave amplitude measurement; and

displaying an indication of said level of confidence.

6. A method of obtaining heartbeat measurements from an ECG waveform, said method comprising the steps of:

detecting a plurality of heartbeats in said ECG waveform;

classifying said plurality of heartbeats as dominant heartbeats and non-dominant heartbeats;

aligning said dominant heartbeats to create aligned dominant heartbeats;

creating a representative heartbeat from said plurality of aligned dominant heartbeats;

obtaining measurements for said representative heartbeat, further comprising the steps of;

obtaining a plurality of representative heartbeats corresponding to a plurality of ECG waveforms;

measuring an earliest QRS onset, responsive to said obtaining step;

measuring a latest QRS offset, responsive to said obtaining step; and

for said representative heartbeat, determining a maximum R wave amplitude measurement between said earliest QRS onset and said latest QRS offset;

for said representative heartbeat, determining an average ST level measurement;

determining a level of confidence of said ST level measurement; and

displaying an indication of said level of confidence.

7. A method of obtaining heartbeat measurements from an ECG waveform, said method comprising the steps of:

detecting a plurality of heartbeats in said ECG waveform;

classifying said plurality of heartbeats as dominant heartbeats and non-dominant heartbeats;

aligning said dominant heartbeats to create aligned dominant heartbeats;

creating a representative heartbeat from said plurality of aligned dominant heartbeats;

obtaining measurements for said representative heartbeat, further comprising the steps of;

obtaining a plurality of representative heartbeats corresponding to a plurality of ECG waveforms;

measuring an earliest QRS onset, responsive to said obtaining step;

measuring a latest QRS offset, responsive to said obtaining step; and

for said representative heartbeat, determining a maximum R wave amplitude measurement between said earliest QRS onset and said latest QRS offset; and

for said representative heartbeat, determining an isoelectric level by computing an average level for a predetermined amount of time prior to said earliest QRS onset.

8. The method of claim 7, further comprising the steps of:

determining a level of confidence of said isoelectric level measurement; and

displaying an indication of said level of confidence.

9. A medical device for obtaining heartbeat measurements from an ECG waveform, comprising:

detection logic for detecting a plurality of heartbeats in said ECG waveform;

classification logic for classifying said plurality of heartbeats as dominant heartbeats and non-dominant heartbeats;

alignment logic for aligning said dominant heartbeats to create aligned dominant heartbeats;

representative heartbeat creation logic for creating a representative heartbeat from said plurality of aligned dominant heartbeats;

measurement logic for obtaining measurements for said representative heartbeat, said measurement logic further comprising;

means for obtaining a plurality of representative heartbeats corresponding to a plurality of ECG waveforms;

means for measuring an earliest QRS onset, responsive to said obtaining means;

means for measuring a latest QRS offset, responsive to said obtaining means;

for said representative heartbeat, means for determining a maximum R wave amplitude measurement between said earliest QRS onset and said latest QRS offset;

for said representative heartbeat, means for determining an average ST level measurement; and

for said representative heartbeat, means for determining an ST slope measurement by using a best line fit between the latest QRS offset and an ST measurement point of said representative heartbeat.

10. The medical device of claim 9, further comprising:

for said representative heartbeat, means for determining an ST integral measurement by computing the sum of the negative area between said latest QRS offset and said ST measurement point of said representative heartbeat.

11. The medical device of claim 10, further comprising:

means for determining a level of confidence of said ST integral measurement; and

means for displaying an indication of said level of confidence.

12. The medical device of claim 9, further comprising:

means for determining a level of confidence of said ST slope measurement; and

means for displaying an indication of said level of confidence.

13. A medical device for obtaining heartbeat measurements from an ECG waveform, comprising:

detection logic for detecting a plurality of heartbeats in said ECG waveform;

classification logic for classifying said plurality of heartbeats as dominant heartbeats and non-dominant heartbeats;

alignment logic for aligning said dominant heartbeats to create aligned dominant heartbeats;

representative heartbeat creation logic for creating a representative heartbeat from said plurality of aligned dominant heartbeats;

measurement logic for obtaining measurements for said representative heartbeat, said measurement logic further comprising;

means for obtaining a plurality of representative heartbeats corresponding to a plurality of ECG waveforms;

means for measuring an earliest QRS onset, responsive to said obtaining means;

means for measuring a latest QRS offset, responsive to said obtaining means;

for said representative heartbeat, means for determining a maximum R wave amplitude measurement between said earliest QRS onset and said latest QRS offset;

means for determining a level of confidence of said maximum R wave amplitude measurement; and

means for displaying an indication of said level of confidence.

14. A medical device for obtaining heartbeat measurements from an ECG waveform, comprising:

detection logic for detecting a plurality of heartbeats in said ECG waveform;

classification logic for classifying said plurality of heartbeats as dominant heartbeats and non-dominant heartbeats;

alignment logic for aligning said dominant heartbeats to create aligned dominant heartbeats;

representative heartbeat creation logic for creating a representative heartbeat from said plurality of aligned dominant heartbeats;

measurement logic for obtaining measurements for said representative heartbeat, said measurement logic further comprising;

means for obtaining a plurality of representative heartbeats corresponding to a plurality of ECG waveforms;

means for measuring an earliest QRS onset, responsive to said obtaining means;

means for measuring a latest QRS offset, responsive to said obtaining means;

for said representative heartbeat, means for determining a maximum R wave amplitude measurement between said earliest QRS onset and said latest QRS offset;

for said representative heartbeat, means for determining an average ST level measurement;

means for determining a level of confidence of said ST level measurement; and

means for displaying an indication of said level of confidence.

15. A medical device for obtaining heartbeat measurements from an ECG waveform, comprising:

detection logic for detecting a plurality of heartbeats in said ECG waveform;

classification logic for classifying said plurality of heartbeats as dominant heartbeats and non-dominant heartbeats;

alignment logic for aligning said dominant heartbeats to create aligned dominant heartbeats;

representative heartbeat creation logic for creating a representative heartbeat from said plurality of aligned dominant heartbeats;

measurement logic for obtaining measurements for said representative heartbeat, said measurement logic further comprising;

means for obtaining a plurality of representative heartbeats corresponding to a plurality of ECG waveforms;

means for measuring an earliest QRS onset, responsive to said obtaining means;

means for measuring a latest QRS offset, responsive to said obtaining means;

for said representative heartbeat, means for determining a maximum R wave amplitude measurement between said earliest QRS onset and said latest QRS offset; and

for said representative heartbeat, means for determining an isoelectric level by computing an average level for a predetermined amount of time prior to said earliest QRS onset.

16. The medical device of claim 15, further comprising:

means for determining a level of confidence of said isoelectric level; and

means for displaying said level of confidence.