Apparatus and method for optimizing cardiac performance by determining the optimal timing interval from an accelerometer signal

Claim 2

A cardiac stimulating apparatus functioning in a preset pacing mode, and programmed to optimize cardiac performance of a patient's heart, comprising: a) a dual chamber cardiac pacer and leads coupled to said cardiac pacer for sensing atrial and ventricular events of a patient's heart and for stimulating preselected chambers of the heart, and further including a cardiac cycle means for identifying cardiac cycles of the patient's heart; b) a cardiac electrogram coupled to said cardiac pacer for identifying R--R intervals of the patient's heart; c) an accelerometer contained within a housing of said cardiac pacer and coupled to a microprocessor based controller of said cardiac pacer, said accelerometer having a filter wherein said accelerometer transmits to the cardiac pacer a waveform having various features associated with mechanical movement events within an atrium and mechanical movement events within a ventricle; and d) said microprocessor based controller including feature means for identifying pre-selected features of the waveform transmitted by the accelerometer, means for corresponding the R--R interval identified by the cardiac electrogram with the features identified by the feature means, and analyzing means for analyzing identified features over corresponding R--R intervals, wherein the identified features are analyzed and compared by said microprocessor over a preselected number of R--R intervals for a plurality of preselected timing intervals, said timing intervals being a time between at least one of intrinsic and paced stimulations of pre-selected chambers of the heart, to thereby determine an optimum timing interval.

Claim 3

The cardiac stimulating apparatus as recited in claim 1 wherein said pre-selected features are selected from the group consisting of an amplitude in the frequency domain of the waveform, an amplitude associated with a first heart sound and an amplitude associated with a second heart sound.

Claim 4

The cardiac stimulating apparatus as recited in claim 1, wherein said microprocessor-based controller analyzes and compares characteristic values of the identified features over the plurality of pre-selected timing intervals.

Claim 5

The cardiac stimulating apparatus as recited in claim 1, wherein said microprocessor-based controller includes a means for identifying, from the waveform transmitted by the accelerometer, a time of physical inactivity.

Claim 6

The cardiac stimulating apparatus as recited in claim 1, further including a respiratory means for identifying complete respiratory cycles and means for corresponding identified respiratory cycles with the features identified by the feature means, whereby the identified features are analyzed and compared over a plurality respiratory cycles.

Claim 7

The cardiac stimulating apparatus as recited in claim 1, wherein the dual chamber cardiac pacer functions in a pacing mode selected from the group consisting of A-V pacing, V--V pacing and A--A pacing.

Claim 8

The cardiac stimulating apparatus as recited in claim 6, wherein the A-V pacing mode is selected from the group consisting of A R -V R pacing, A R -V L pacing, A L -V R pacing, A R - V RL pacing, A L -V RL pacing, and A L -V L pacing.

Claim 9

A cardiac stimulating apparatus functioning in a rate adaptive preset pacing mode, and programmed to optimize cardiac performance of a patient's heart, comprising: a) a dual chamber cardiac pacer and leads coupled to said cardiac pacer for sensing atrial and ventricular events of a patient's heart and for stimulating preselected chambers of the heart, and further including a cardiac cycle means for identifying cardiac cycles of the patient's heart; b) a cardiac electrogram coupled to said cardiac pacer for identifying R--R intervals of the patient's heart; c) an accelerometer contained within a housing of said cardiac pacer and coupled to a microprocessor based controller of said cardiac pacer, said accelerometer having a filter wherein said accelerometer transmits to the cardiac pacer a waveform having various features associated with mechanical movement events within an atrium and mechanical movement events within a ventricle; and d) said microprocessor based controller including feature means for identifying pre-selected features of the waveform transmitted by the accelerometer, respiratory means coupled to said cardiac pacer for identifying complete respiratory cycles, means for corresponding both the R--R interval identified by the cardiac electrogram and the respiratory cycles identified by the respiratory means with the features identified by the feature means, and analyzing means for analyzing identified features over corresponding R--R intervals and respiratory cycles, wherein the identified features are analyzed and compared by said microprocessor over a preselected number of at least one of R--R intervals and respiratory cycles for a plurality of preselected timing intervals, said timing intervals being a time between at least one of intrinsic and paced stimulations of pre-selected chambers of the heart, to thereby determine an optimum timing interval.

Claim 10

A cardiac stimulating apparatus functioning in a rate adaptive preset pacing mode, and programmed to optimize cardiac performance of a patient's heart, comprising: a) a dual chamber cardiac pacer and leads coupled to said cardiac pacer for sensing atrial and ventricular events of a patient's heart and for stimulating preselected chambers of the heart, and further including a cardiac cycle means for identifying cardiac cycles of the patient's heart; b) a cardiac electrogram coupled to said cardiac pacer for identifying R--R intervals of the patient's heart; c) an accelerometer contained within a housing of said cardiac pacer and coupled to a microprocessor based controller of said cardiac pacer, said accelerometer having a filter wherein said accelerometer transmits to the cardiac pacer a waveform having various features associated with mechanical movement events within an atrium and mechanical movement events within a ventricle; and d) said microprocessor based controller including feature means for identifying pre-selected features of the waveform transmitted by the accelerometer, respiratory means coupled to said cardiac pacer for identifying complete respiratory cycles, means for corresponding both the R--R interval identified by the cardiac electrogram and the respiratory cycles identified by the respiratory means with the features identified by the feature means, and analyzing means for analyzing identified features over corresponding R--R intervals and respiratory cycles, wherein the identified features are analyzed and compared by said microprocessor over a preselected number of at least one of R--R intervals and respiratory cycles for a plurality of preselected timing intervals, said timing intervals being a time between at least one of intrinsic and paced stimulations of pre-selected chambers of the heart, to thereby determine an optimum timing interval.

Claim 11

The cardiac stimulating apparatus as recited in claim 8, wherein said pre-selected features are selected from the group consisting of an amplitude in the frequency domain of the waveform, an amplitude associated with a first heart sound and an amplitude associated with a second heart sound.

Claim 12

The cardiac stimulating apparatus as recited in claim 8, wherein said microprocessor-based controller analyzes and compares characteristic values of the identified features over the plurality of pre-selected timing intervals.

Claim 13

The cardiac stimulating apparatus as recited in claim 8, wherein said microprocessor-based controller includes a means for identifying, from the waveform transmitted by the accelerometer, a time of physical inactivity.

Claim 14

The cardiac stimulating apparatus as recited in claim 8, wherein the dual chamber cardiac pacer functions in a pacing mode selected from the group consisting of A-V pacing, V--V pacing and A--A pacing.

Claim 15

The cardiac stimulating apparatus as recited in claim 12, wherein the A-V pacing mode is selected from the group consisting of A R -V R pacing, A R -V L pacing, A L -V R pacing, A R -V RL pacing, A L -V RL pacing, and A L -V L pacing.

Claim 18

The method as in claim 14, and further including, before step b), the further step of inhibiting the steps of b)-j) if a level of physical activity of the patient determined from the signal received from the accelerometer is greater than a predetermined amount.

Claim 19

The method as in claim 14 and further including the step of waiting a predetermined amount of time between steps b) and c).

Claim 20

The method as in claim 14, further including the step of selecting a pacing mode of the implantable cardiac pacer from a group consisting of A-V pacing, V--V pacing and A--A pacing.

Claim 21

The method as recited in claim 17, further including the step of selecting the A-V pacing mode from the group consisting of A R -V R pacing, A R -V L pacing, A L -V R pacing, A R -V RL pacing, A L -V RL pacing, and A L -V L pacing.

Claim 22

The method as recited in claim 14, wherein the pre-selected features are selected from the group consisting of an amplitude in the frequency domain of the waveform, an amplitude associated with a first heart sound and an amplitude associated with a second heart sound.

Claim 23

The method as recited in claim 14, wherein the predetermined set of timing interval values comprise alternation between a baseline value and a randomly selected timing interval value.