Use of activation and recovery times and dispersions to monitor heart failure status and arrhythmia risk

• US 20040220635A1
• Filed: 04/29/2003
• Published: 11/04/2004
• Est. Priority Date: 04/29/2003
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Burnes, John E.
• Granted Patent: US 7,107,093 B2
• Time in Patent Office: Days
• US Class Current: 607/17
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• CPC Class Codes: A61N 1/3684 for stimulating the heart at multiple sites of the ventricle or the atrium
• CPC Class Codes: A61N 1/36842 Multi-site stimulation in the same chamber
• CPC Class Codes: A61N 1/36843 Bi-ventricular stimulation

Abstract

A system and method for monitoring electrical dispersion of the heart is provided including an implantable medical device and associated electrode system for sensing cardiac signals from a combination of two or more local and/or global EGM sensing vectors and/or subcutaneous ECG sensing vectors. Activation and recovery times and the activation-recovery intervals are measured from a selected cardiac cycle for each sensing vector. Dispersion is determined as the differences between activation times, recovery times and/or ARIs measured from each of the sensing vectors. An increase in dispersion indicates a worsening of heart failure and/or an increased risk of arrhythmias. Accordingly, a cardiac therapy may be delivered or adjusted in response to a detected increase in dispersion.

Claims

1. A method for monitoring a heart, comprising:

detecting a plurality of signals associated with electrical activity of a heart at a plurality of sensing sites, wherein a plurality of addressable electrodes produce a plurality of sensing vectors at the plurality of sensing sites;

measuring an activation time for a given cardiac cycle for each of the detected plurality of signals;

measuring a recovery time for the given cardiac cycle from each of the detected signals;

calculating an activation recovery interval as the difference between the activation time and the recovery time for each said detected plurality of signals; and

calculating at least a one of;

a dispersion of activation time, a recovery time, an activation recovery interval.

2. A method according to claim 1, wherein if a subsequent comparison of a prior dispersion of activation time, a prior recovery time, or a prior activation recovery interval reveals an increased dispersion of activation time, an increased recovery time or an increased activation-recovery interval further comprising:

declaring a worsening heart failure condition.

3. A method according to claim 1, wherein if a subsequent comparison of a prior dispersion of activation time, a prior recovery time, or a prior activation recovery interval reveals an increased dispersion of activation time, an increased recovery time or an increased activation-recovery interval further comprising:

declaring an increased risk for arrhythmias.

4. A method according to claim 1, further comprising:

delivering a cardiac pacing therapy in response to an increase in a one of;

a dispersion of activation time, a recovery time, an activation recovery interval dispersion.

5. A method according to claim 1, further comprising:

adjusting a cardiac pacing therapy until a relative decrease occurs in a one of;

a dispersion of activation time,

a recovery time,

an activation recovery interval.

6. An apparatus for monitoring a heart, comprising:

means for detecting a plurality of signals associated with electrical activity of a heart at a plurality of sensing sites, wherein a plurality of addressable electrodes produce a plurality of sensing vectors at the plurality of sensing sites;

means for measuring an activation time for a given cardiac cycle for each of the detected plurality of signals;

means for measuring a recovery time for the given cardiac cycle from each of the detected signals;

means for calculating an activation recovery interval as the difference between the activation time and the recovery time for each said detected plurality of signals; and

means for calculating at least a one of;

a dispersion of activation time, a recovery time, an activation recovery interval.

7. An apparatus according to claim 6, wherein if a subsequent comparison of a prior dispersion of activation time, a prior recovery time, or a prior activation recovery interval reveals an increased dispersion of activation time, an increased recovery time or an increased activation-recovery interval further comprising:

means for declaring a worsening heart failure condition.

8. An apparatus according to claim 6, wherein if a subsequent comparison of a prior dispersion of activation time, a prior recovery time, or a prior activation recovery interval reveals an increased dispersion of activation time, an increased recovery time or an increased activation-recovery interval further comprising:

means for declaring an increased risk for arrhythmias.

9. A method according to claim 6, further comprising:

means for delivering a cardiac pacing therapy in response to an increase in a one of;

a dispersion of activation time, a recovery time, an activation recovery interval dispersion.

10. A method according to claim 6, further comprising:

means for adjusting a cardiac pacing therapy until a relative decrease occurs in a one of;

a dispersion of activation time,

a recovery time,

an activation recovery interval.

11. A computer readable medium for storing executable instructions for performing a method for monitoring a heart, comprising:

instructions for detecting a plurality of signals associated with electrical activity of a heart at a plurality of sensing sites, wherein a plurality of addressable electrodes produce a plurality of sensing vectors at the plurality of sensing sites;

instructions for measuring an activation time for a given cardiac cycle for each of the detected plurality of signals;

instructions for measuring a recovery time for the given cardiac cycle from each of the detected signals;

instructions for calculating an activation recovery interval as the difference between the activation time and the recovery time for each said detected plurality of signals; and

instructions for calculating at least a one of;

a dispersion of activation time, a recovery time, an activation recovery interval.

12. A medium according to claim 11, wherein if a subsequent comparison of a prior dispersion of activation time, a prior recovery time, or a prior activation recovery interval reveals an increased dispersion of activation time, an increased recovery time or an increased activation-recovery interval further comprising:

instructions for declaring a worsening heart failure condition.

13. A medium according to claim 11, wherein if a subsequent comparison of a prior dispersion of activation time, a prior recovery time, or a prior activation recovery interval reveals an increased dispersion of activation time, an increased recovery time or an increased activation-recovery interval further comprising:

instructions for declaring an increased risk for arrhythmias.

14. A medium according to claim 11, further comprising:

instructions for delivering a cardiac pacing therapy in response to an increase in a one of;

a dispersion of activation time, a recovery time, an activation recovery interval dispersion.

15. A medium according to claim 11, further comprising:

instructions for adjusting a cardiac pacing therapy until a relative decrease occurs in a one of;

a dispersion of activation time,

a recovery time,

an activation recovery interval.