Cardiac event detection over varying time scale

• US 20090216141A1
• Filed: 02/10/2009
• Published: 08/27/2009
• Est. Priority Date: 11/26/2003
• Status: Active Grant

• Current Assignee: Angel Medical Systems, Inc.
• Original Assignee: Angel Medical Systems, Inc.
• Inventors: Fischell, David R., Fischell, Robert E., Johnson, Steven R., Harwood, Jonathan
• Granted Patent: US 8,244,338 B2
• Time in Patent Office: Days
• US Class Current: 600/509
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/02405 Determining heart rate variability
• CPC Class Codes: A61B 5/02455 provided with high/low alarm devices
• CPC Class Codes: A61B 5/29 for permanent or long-term implantation
• CPC Class Codes: A61B 5/329 Load diagnosis, e.g. cardiac stress tests
• CPC Class Codes: A61B 5/33 specially adapted for cooperation with other devices
• CPC Class Codes: A61B 5/339 Displays specially adapted therefor
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/358 Detecting ST segments
• CPC Class Codes: A61B 5/366 Detecting abnormal QRS complex, e.g. widening
• CPC Class Codes: A61B 5/413 Monitoring transplanted tissue or organ, e.g. for possible rejection reactions after a transplant
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• 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: A61N 1/025 Digital circuitry features of electrotherapy devices, e.g. memory, clocks, processors
• CPC Class Codes: A61N 1/37211 Means for communicating with stimulators
• CPC Class Codes: A61N 1/37247 User interfaces, e.g. input or presentation means

Abstract

Disclosed is a “tracker system” that includes implanted electrical leads which are part of an implanted cardiotracker plus external equipment that includes external alarm means and a physician'"'"'s programmer. The tracker system is designed to monitor the degradation of a patient'"'"'s cardiovascular condition from one or more causes. These causes include the rejection of a transplanted heart and/or the progression of a stenosis in a coronary artery. As one or more stenoses in a coronary artery become progressively more narrow thereby causing reduced blood flow to the heart muscle coronary circulation, the tracker system can alert the patient by either or both internal and/or external alarm means to take the appropriate medical action. The physician'"'"'s programmer can be used to display histograms of key heart signal parameters that are indicative of the patient'"'"'s cardiovascular condition.

Claims

1. A device for tracking the cardiovascular condition of a human patient the system including:

at least two implanted electrodes that are positioned within the human patient to sense the electrical signal from the patient'"'"'s heart, the electrical signal consisting of a multiplicity of beats;

a memory;

a processor configured to

(a) compute from the electrical signal a heart signal parameter'"'"'s average value over a time period for each of a multiplicity of heart rate ranges, thereby generating a multiplicity of average values, wherein the time period is at least 24 hours;

(b) store the multiplicity of average values in the memory according to both time period and heart rate,

(c) repeat (a) and (b) for a multiplicity of time periods, thereby generating, for each heart rate range, a time series of average values of the parameter.

2. The device of claim 1 further including a transmitter for sending to an external device the time series of average values for each heart rate bin.

3. The device of claim 1 wherein the processor is further configured to analyze at least one of the time series of average values to generate a trend curve that describes changes in the average values over time.

4. The device of claim 3 further including an alarm, and wherein the processor is further configured to generate an alarm if the trend of the average values indicates a pathological condition.

5. The device of claim 3 wherein the trend is based on a moving average of the time series of average values.

6. The device of claim 1 wherein the processor is further configured to store heart signal parameter value histograms for each of the multiplicity of heart rate ranges, and wherein each of the multiplicity of average values is determined according to data in a corresponding histogram.

7. The device of claim 1 wherein the heart signal parameter is ST segment deviation.

8. A device for tracking the cardiovascular condition of a human patient the system including:

at least two implanted electrodes that are positioned within the human patient to sense the electrical signal from the patient'"'"'s heart, the electrical signal consisting of a multiplicity of beats;

a memory;

a transceiver;

a processor configured to

(a) compute from the electrical signal a heart signal parameter'"'"'s average value over a multiplicity of time periods, thereby generating a time series of average values, wherein each of multiplicity of time periods is at least 24 hours;

(b) store the time series of average values in the memory,

(c) generating a trend curve that describes changes in the average values over time;

(d) if the trend curve meets a specified criterion, control the transceiver to send an appropriate alert to an external device.

9. The device of claim 8 wherein the trend curve is based on a moving average of the time series of average values.

10. The device of claim 8 wherein the criterion is based on the difference between a maximum value and a minimum value of the trend curve over a predetermined time.

11. The device of claim 8 wherein the multiplicity of average values are computed over a particular heart rate range.

12. A device for tracking the cardiovascular condition of a human patient the system including:

at least two implanted electrodes that are positioned within the human patient to sense the electrical signal from the patient'"'"'s heart, the electrical signal consisting of a multiplicity of beats;

a memory;

a transceiver;

a processor configured to

(a) compute from the electrical signal a heart signal parameter'"'"'s average value over a multiplicity of time periods, thereby generating a time series of average values, wherein each of the multiplicity of time periods is at least 24 hours;

(b) store the time series of average values in the memory,

(c) operative upon receipt of a request for data received through the transceiver from an external device, control the transceiver to send the time series of average values.