METHODS AND DEVICES FOR MONITORING MYOCARDIAL MECHANICAL STABILITY

• US 20100179610A1
• Filed: 10/09/2009
• Published: 07/15/2010
• Est. Priority Date: 06/02/2006
• Status: Active Grant

• Current Assignee: Euljoon Park, Taraneh Ghaffari Farazi
• Original Assignee: Euljoon Park, Taraneh Ghaffari Farazi
• Inventors: Farazi, Taraneh Ghaffari, Park, Euljoon
• Granted Patent: US 8,606,352 B2
• Time in Patent Office: Days
• US Class Current: 607/17
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/029 Measuring or recording blood output from the heart, e.g. minute volume A61B8/065 takes precedence
• CPC Class Codes: A61B 5/0295 using plethysmography, i.e. measuring the variations in the volume of a body part as modified by the circulation of blood therethrough, e.g. impedance plethysmography
• CPC Class Codes: A61B 5/0535 Impedance plethysmography for measuring blood flow A61B5/0295
• CPC Class Codes: A61B 5/1107 Measuring contraction of parts of the body, e.g. organ, muscle apparatus for measuring work or force in general G01L
• CPC Class Codes: A61B 5/1459 invasive, e.g. introduced into the body by a catheter A61B5/1464 takes precedence
• CPC Class Codes: A61B 5/287 Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/6852 Catheters
• 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: A61B 7/023 for introduction into the body, e.g. into the oesophagus oesophageal ECG probes A61B5/285
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: A61N 1/36521 the parameter being derived from measurement of an electrical impedance
• CPC Class Codes: A61N 1/37258 Alerting the patient
• CPC Class Codes: A61N 1/39622 Pacing therapy

Abstract

Embodiments of the present invention relate to implantable systems, and methods for use therewith, for monitoring myocardial mechanical stability based on a signal that is indicative of mechanical functioning of a patient'"'"'s heart for a plurality of consecutive beats. Certain embodiments use time domain techniques, while other embodiments use frequency domain techniques, to monitor myocardial mechanical stability. In certain embodiments the patient'"'"'s heart is paced using a patterned pacing sequence that repeats every N beats. In other embodiments, the patient'"'"'s heart need not be paced. This abstract is not intended to be a complete description of, or limit the scope of, the invention.

Claims

1. In an implantable system, a method for monitoring myocardial mechanical stability based on a signal that is indicative of mechanical functioning of the patient'"'"'s heart for a plurality of consecutive beats, the method comprising:

(a) dividing the plurality of consecutive beats into a plurality of sets of N consecutive beats, where N is an integer that is at least 3;

(b) for each set of N consecutive beats, selecting 2 of the N beats to produce a sub-set of 2 beats per set of N consecutive beats;

(c) transforming time domain data, associated with the plurality of sub-sets of 2 beats, to frequency domain data; and

(d) monitoring myocardial mechanical stability based on the frequency domain data.

2. The method of claim 1, wherein the signal is obtained as the patient'"'"'s heart is paced for a period of time using a patterned pacing sequence that repeats every N beats, so that the signal that is indicative of mechanical functioning of the patient'"'"'s heart for a plurality of consecutive beats while the patient'"'"'s heart is being paced using the patterned pacing sequence that repeats every N beats.

3. The method of claim 1, wherein step (d) includes determining, based on the alternans magnitude at 0.5 cycles/beat, whether mechanical alternans are present.

4. The method of claim 1, wherein step (d) includes tracking changes in the alternans magnitude at 0.5 cycles/beat as steps (a) through (c) are repeated over time, to thereby track changes in myocardial mechanical stability.

5. The method of claim 1, wherein the selecting 2 of the N beats, for each set of N consecutive beats at step (d), comprises selecting 2 consecutive beats from each set of N beats.

6. The method of claim 5, wherein the selecting 2 of the N beats, for each set of N consecutive beats at step (c), comprises selecting the first 2 beats from each set of N beats.

7. The method of claim 1, further comprising analyzing the mechanical signal obtained at step (b) to compensate for ectopic beats prior to the dividing at step (c).

8. An implantable system for monitoring myocardial mechanical stability based on a signal that is indicative of mechanical functioning of the patient'"'"'s heart for a plurality of consecutive beats, the system comprising:

one or more sensor to obtain the signal that is indicative of mechanical functioning of the patient'"'"'s heart for a plurality of consecutive beats; and

a controller to

divide the plurality of consecutive beats into a plurality of sets of N consecutive beats, where N is an integer that is at least 3;

select 2 of the N beats to produce a sub-set of 2 beats per set of N consecutive beats, for each set of N consecutive beats;

transform time domain data, associated with the plurality of sub-sets of 2 beats, to frequency domain data; and

monitor myocardial mechanical stability based on the frequency domain data.

9. The system of claim 8, further comprising one or more pulse generator to pace the patient'"'"'s heart for a period of time using a patterned pacing sequence that repeats every N beats;

and wherein the one or more sensor obtains the signal that is indicative of mechanical functioning of the patient'"'"'s heart for a plurality of consecutive beats while the patient'"'"'s heart is being paced using the patterned pacing pattern that repeats every N beats.

10. The system of claim 8, wherein the controller determines, based on the frequency domain data, an alternans magnitude at 0.5 cycles/beat, and monitors myocardial mechanical stability based on the alternans magnitude at 0.5 cycles/beat.

11. The system of claim 10, wherein the controller monitors myocardial mechanical stability by determining, based on the alternans magnitude at 0.5 cycle/beat, whether mechanical alternans are present.

12. The system of claim 10, wherein the controller tracks changes in the alternans magnitude at 0.5 cycles/beat over time, to thereby track changes in myocardial mechanical stability.

13. The system of claim 8, wherein the controller selects 2 of the N beats, for each set of N consecutive beats, by selecting 2 consecutive beats from each set of N beats.

14. The system of claim 13, wherein the controller selects 2 of the N beats, for each set of N consecutive beats, by selecting the first 2 beats from each set of N beats.

15. The system of claim 8, wherein the controller analyzes the signal to compensate for ectopic beats prior to dividing the plurality of consecutive beats into a plurality of sets of N consecutive beats.