SYSTEM AND METHOD FOR HEART MONITORING

• US 20070191722A1
• Filed: 04/23/2007
• Published: 08/16/2007
• Est. Priority Date: 03/05/2004
• Status: Active Grant

• Current Assignee: Lifesciences Solutions LLC
• Original Assignee: Lifesciences Solutions LLC
• Inventors: Richardson, Charles, Kellar, Franz, Smith, Michael
• Granted Patent: US 10,499,828 B2
• Time in Patent Office: Days
• US Class Current: 600/510
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/35 by template matching
• CPC Class Codes: A61B 5/413 Monitoring transplanted tissue or organ, e.g. for possible rejection reactions after a transplant
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371
• 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
• CPC Class Codes: A61N 1/37282 characterised by communication with experts in remote locations using a network

Abstract

The present invention provides systems and methods for monitoring a heart. According to one embodiment, the system includes an implantable registering unit for registering an electrical signal from the heart. The system includes a local data unit in operable communication with registering unit. The local data unit may be placed in communication with a computer, which may be at a location remote from the local data unit. The computer is adapted to receive the data from the local data unit corresponding to the registered electrical signal and to compare the registered electrical signal to a reference electrical signal to determine whether the heart is functioning properly.

Claims

1. A method of monitoring a transplanted heart, comprising:

(a) during a first data collection session occurring at a reference time, registering an electrical signal from a patient'"'"'s heart, the electrical signal configured as a first series of waveforms;

(b) generating from the first series of waveforms, a reference waveform representative of the average characteristics of the waveforms collected during the first data collection session;

(c) during a subsequent data session occurring at a time subsequent to the reference time, registering an electrical signal from a patient'"'"'s heart, the electrical signal configured as a second series of waveforms;

(d) generating from the second series of waveforms, a registered waveform representative of the average characteristics of the waveforms collected during the subsequent data collection session; and

(e) comparing the registered waveform to the reference waveform to determine whether the heart is functioning properly.

2. The method of claim 1 in which step (e) is carried out by:

(a) measuring the difference between at least one element of the registered waveform and a corresponding element of the reference waveform; and

(b) characterizing the difference in a scale of rejection in which a greater degree of difference corresponds to a greater degree of allograft rejection.

3. The method of claim 1 further comprising repeating steps (c)-(d) at selected intervals after the reference time so as to generate a plurality of registered waveforms.

4. The method of claim 3 in which step (e) is carried out by:

(a) adding the plurality of registered waveforms to a statistical database to create a data population;

(b) determining at least one difference between the registered waveforms and the reference waveform based on a statistical analysis of a plurality of elements of the registered waveforms and corresponding elements of the reference waveform; and

(c) characterizing the difference in a scale of rejection in which a greater degree of difference corresponds to a greater degree of allograft rejection.

5. The method of claim 1 further comprising:

(f) prior to step (b), evaluating whether each of the waveforms in the first series is usable according to a predetermined standard;

(g) discarding waveforms from the first series which are not usable; and

(h) storing the remaining waveforms of the first series in a database for use in generating the reference waveform;

6. The method of claim 1 further comprising:

(f) prior to step (b), evaluating whether each of the waveforms in the subsequent series is usable according to a predetermined standard;

(g) discarding waveforms from the subsequent series which are not usable; and

(h) storing the remaining waveforms of the subsequent series in a database for use in generating the registered waveform;

7. A method of monitoring a transplanted heart, comprising:

(a) during a data collection session, registering an electrical signal from a patient'"'"'s heart, the electrical signal configured as a series of waveforms;

(b) evaluating whether each of the waveforms is usable according to a predetermined standard;

(c) discarding waveforms which are not usable;

(d) storing the remaining waveforms in a database for evaluation; and

(e) comparing the stored waveforms to a reference waveform to determine whether the heart is functioning properly.

8. The method of claim 7 further comprising:

(a) incrementing a discard counter each time a waveform is discarded;

(b) comparing the value of the discard counter to a predetermined limit; and

(c) setting an error flag if the discard counter exceeds a predetermined limit.

9. The method of claim 7 further comprising generating, from the remaining waveforms, an average waveform representative of the average characteristics of all of the waveforms collected during the data collection session.

10. The method of claim 7 further comprising:

(f) storing a first set of waveforms according to steps (a)-(d) during a first data session occurring at a reference time;

(g) generating from the remaining waveforms in the first data collection session, the reference waveform, wherein the reference waveform is representative of the average characteristics of the waveforms stored during the first data collection session;

(h) storing a subsequent set of waveforms according to steps (a)-(d) during a subsequent data collection session occurring at a time subsequent to the reference time; and

(i) generating from the remaining waveforms in the subsequent data collection session, a registered waveform representative of the average characteristics of the waveforms stored during the subsequent data collection session.

11. The method of claim 10 comprising repeating steps (h) and (i) at selected intervals after the reference time so as to generate a plurality of registered waveforms.

12. The method of claim 10 wherein the reference time is shortly after the heart is transplanted into the patient.

13. A method of processing data for monitoring a patient'"'"'s heart, comprising:

(a) during a data collection session, registering an electrical signal from a patient'"'"'s heart, the electrical signal configured as a series of waveforms, wherein each of said waveforms represents a QRS complex of a myocardial electrogram including at least one upslope element extending to a peak;

(b) establishing a minimum slope value;

(c) comparing the actual slope value of each portion of the upslope to the minimum slope value; and

(c) designating any point within the waveform in which the actual slope value is less than the minimum slope value to be a peak.

14. The method of claim 13 further comprising:

(a) establishing the time value at which the peak occurs;

(b) applying a hysteresis band with predetermined upper and lower voltage limits to the waveform of the QRS complex;

(c) calculating a voltage-time slope for a segment of the upslope immediately preceding the peak;

(d) using the calculated voltage-time slope, linearly extrapolating the upslope to a point at which a voltage value thereof intercepts the upper limit of the hysteresis band; and

(e) establishing the time value at which the interception occurs.

15. A system for monitoring a patient'"'"'s heart, comprising:

(a) a registering unit structured to be implanted into the patient'"'"'s body, the registering unit adapted to be connected in electrical communication with the patient'"'"'s heart and to register an electrical signal from the patient'"'"'s heart; and

(b) a local data unit in operable communication with the registering unit and adapted to receive data corresponding to the registered electrical signal, the local data unit adapted to transmit data over a remote communications link to a computer.

16. The system of claim 15 wherein the registering unit further comprises an RF transmitter in operable communication with the local data unit.

17. The system of claim 15 further comprising a relay unit adapted to be inductively coupled to the registering unit and to communicate with the computer, the relay unit adapted to receive data from the registering unit corresponding to the registered electrical signal and to transfer the received data to the local data unit.

18. The system of claim 15 wherein the local data unit includes a data repository for storing data corresponding to the registered electrical signal.

19. The system of claim 15 further comprising:

(a) a computer including a database, the computer programmed to receive data from the local data unit and store the data in the database; and

(b) a remote communications link interconnecting the local data unit and the computer;

(c) wherein the computer is programmed to compare the data corresponding to the registered electrical signal to a reference electrical signal to determine whether the patient'"'"'s heart is functioning properly.

20. The system of claim 19 wherein the computer is a data server situated at a location remote from the local data unit.

21. The system of claim 19 wherein the computer forms a part of the local data unit.

22. A system according to claim 19 wherein:

(a) the reference electrical signal is represented as a first waveform which is an average of a first plurality of recorded waveforms recorded at a first time; and

(b) the registered electrical signal is represented as a second waveform which is an average of a second plurality of recorded waveforms recorded at a second time after the first time.

23. The system according to claim 22 wherein the reference and registered electrical signal are QRS complexes of an intracardiac electrogram, or portions thereof.