Cardiac rhythm management system with arrhythmia prediction and prevention

• US 6,400,982 B2
• Filed: 05/07/2001
• Issued: 06/04/2002
• Est. Priority Date: 10/01/1999
• Status: Expired due to Term

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Sweeney, Robert J., KenKnight, Bruce H.
• Primary Examiner(s): Kamm, William E
• Application Number:
  US09/850,283
• Publication Number:
  US 20010020136A1
• Time in Patent Office: 393 Days
• Field of Search: 600/510, 600/515, 600/516, 600/518
• US Class Current: 600/515
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: G16H 50/30 for calculating health indices; for individual health risk assessment
• CPC Class Codes: G16Z 99/00 Subject matter not provided for in other main groups of this subclass

Abstract

A cardiac rhythm management system predicts when an arrhythmia will occur and in one embodiment invokes a therapy to prevent or reduce the consequences of the arrhythmia. A cardiac arrhythmia trigger/marker is detected from a patient, and based on the trigger/marker, the system estimates a probability of a cardiac arrhythmia occurring during a predetermined future time interval. The system provides a list of triggers/markers, for which detection values are recurrently obtained at various predetermined time intervals. Based on detection values and conditional probabilities associated with the triggers/markers, a probability estimate of a future arrhythmia is computed. An arrhythmia prevention therapy is selected and activated based on the probability estimate of the future arrhythmia.

Claims

1. A cardiac rhythm management system, including:

a sensing module for detecting conditioning events statistically associated with occurrences of arrhythmias; and

,

an arrhythmia prediction module for predicting the occurrence of an arrhythmia within a specified prediction time period if an estimated arrhythmia probability exceeds a specified threshold value, wherein the estimated arrhythmia probability is computed from a conditional arrhythmia probability associated with the conditioning event that is derived from past observations of instances in which the conditioning event occur s alone or together with an arrhythmia within a specified time period.

2. The system of claim 1 wherein the sensing module detects conditioning events selected from a group consisting of a specific morphology of a waveform representing electrical activity of the heart, a specific pattern of activation times of different areas of the heart as sensed by a plurality of electrodes, a specific sequence pattern of heartbeats with respect to time, a value of a measured physiological variable, and a statistic based upon a history of occurrences of conditioning events.

3. The system of claim 1 wherein the sensing module detects a plurality of conditioning events statistically associated with the occurrence of an arrhythmia and further wherein the arrhythmia prediction module compares a composite estimated arrhythmia probability with the threshold value in order to predict the occurrence of an arrhythmia, the composite arrhythmia probability being a combination of the estimated arrhythmia probabilities associated with each detected conditioning event.

4. The system of claim 3 wherein the conditional arrhythmia probabilities are based upon past observations of the occurrences of events and arrhythmias taken from population data.

5. The system of claim 3 further comprising an adaptive processing module for computing conditional arrhythmia probabilities based upon past observations of the occurrences of events and arrhythmias taken in real-time from a particular patient.

6. The system of claim 5 wherein the conditional arrhythmia probabilities computed by the adaptive processing module are based initially upon past observations of the occurrences of events and arrhythmias taken from population data and each probability is subsequently updated from a previous value to a present value with observations taken in real-time from a particular patient.

7. The system of claim 6 wherein the adaptive processing module tests the amount by which the present value differs from the previous value for statistical significance before updating a conditional arrhythmia probability.

8. The system of claim 5 wherein the adaptive processing module tests the statistical association of a conditional arrhythmia probability with real-time observation data and discontinues use of a conditional arrhythmia probability in deriving a composite conditional probability if the statistical association is below a specified value.

9. The system of claim 1 further comprising a therapy module for delivering a preventive arrhythmia therapy if the estimated arrhythmia probability exceeds a therapy threshold.

10. The system of claim 9 further comprising a preventive therapy control module for selecting a particular therapy to be delivered from a group of one or more available therapy modalities.

11. The system of claim 10 wherein the group of available therapy modalities includes at least one of:

delivery of one or more of a plurality of pharmacological agents, cardiac pacing in a selected pacing mode, delivery of cardioversion/defibrillation shocks, and neural stimulation.

12. The system of claim 10 wherein the selection of a particular therapy to be delivered by the therapy control module is based upon ascertaining a physiologic state of the patient and deciding whether or not a particular available modality of therapy is appropriate for delivery to the patient in that physiologic state.

13. The system of claim 12 wherein the physiologic state ascertained for selecting a therapy modality by the therapy control module includes at least one of:

the prediction time period of the estimated arrhythmia probability, the particular conditioning events used to make the arrhythmia prediction, the presence or not of specific conditioning events within a specified prior time period, and the magnitude of a measured physiologic variable.

14. The system of claim 13 wherein the therapy control module decides whether or not to deliver a particular mode of preventive therapy by performing a matrix mapping of a list of detected conditioning events to a specific therapy or therapies considered most appropriate for preventing an arrhythmia in that physiologic state, wherein the matrix mapping is performed using a translation matrix containing information relating to the appropriateness of a particular therapy modality for a given detected conditioning event, and further wherein the mapping results in a score for each therapy modality represented in the matrix that is indicative of the appropriateness of each such therapy modality given the list of detected conditioning events, the score being evaluated by the therapy control module.

15. The system of claim 13 wherein the therapy control module decides whether or not to deliver a particular mode of preventive therapy by performing matrix mapping of a state vector representing a specific physiologic state to a specific therapy or therapies considered most appropriate for preventing an arrhythmia in that physiologic state, wherein the matrix mapping is performed using a therapy matrix containing information relating to the appropriateness of a particular therapy modality for a given physiologic state.