초록 ▼

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. Act

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.

대표청구항 ▼

The invention claimed is: 1. A method for monitoring a heart, comprising: detecting a plurality of localized electrogram (EGM) 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

The invention claimed is: 1. A method for monitoring a heart, comprising: detecting a plurality of localized electrogram (EGM) 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 within a single chamber of the heart; measuring an activation time for a given cardiac cycle for each of the detected plurality of localized EGM signals; measuring a recovery time for the given cardiac cycle from each of the detected plurality of localized EGM signals; calculating an activation recovery interval as the difference between the activation time and the recovery time for each said detected plurality of localized EGM signals; and calculating at least a one of: a dispersion of activation time, a recovery time, an activation recovery interval based on the detected plurality of localized EGM signals. 2. A method according to claim 1, wherein in the event that a comparison of the value of an earlier calculated activation recovery interval with a subsequently calculated activation recovery interval reveals a temporally increasing activation recovery interval, then: declaring a worsening heart failure condition. 3. A method according to claim 1, wherein in the event that a comparison of the value of an earlier calculated activation recovery interval with a subsequently calculated activation recovery interval reveals a temporally increasing activation recovery interval, then: declaring an increased risk for arrhythmias. 4. A method according to claim 1, further comprising: delivering a cardiac pacing therapy in response to a relative increase in the activation recovery interval dispersion between a prior and a subsequent calculation of the activation recovery interval. 5. A method according to claim 1, further comprising: adjusting a cardiac pacing therapy until a relative decrease occurs in the activation recovery interval between a prior and a subsequent calculation of the activation recovery interval. 6. An apparatus for monitoring a heart, comprising: means for detecting a plurality of localized electrogram (EGM) 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 disposed within a single chamber of the heart; means for measuring an activation time for a given cardiac cycle for each of the detected plurality of localized EGM signals; means for measuring a recovery time for the given cardiac cycle from each of the detected plurality of localized EGM 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 localized EGM 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 in the event that a comparison of the value of an earlier calculated activation recovery interval with a subsequently calculated activation recovery interval reveals a temporally increasing activation recovery interval, then: means for declaring a worsening heart failure condition. 8. An apparatus according to claim 6, wherein in the event that a comparison of the value of an earlier calculated activation recovery interval with a subsequently calculated activation recovery interval reveals a temporally increasing activation recovery interval, then further comprising: means for declaring an increased risk for arrhythmias. 9. An apparatus according to claim 6, further comprising: means for delivering a cardiac pacing therapy in response to a relative increase in the activation recovery interval dispersion between a prior and a subsequent calculation of the activation recovery interval. 10. An apparatus according to claim 6, further comprising: means for adjusting a cardiac pacing therapy until a relative decrease occurs in the activation recovery interval between a prior and a subsequent calculation of the activation recovery interval. 11. An apparatus according to claim 6, further comprising: an implantable medical device (IMD) housing the apparatus; and electronic circuitry means operatively disposed within the IMD for operatively carrying out the plurality of recited functions. 12. An apparatus according to claim 11, wherein the IMD comprises therapy delivery means for delivering a therapy responsive to the calculated one of: the dispersion of activation time, the recovery time, the activation recovery interval. 13. An apparatus according to claim 12, wherein the IMD comprises one of: a drug delivery device, a spinal cord stimulation device, a dual chamber pacemaker, a cardiac resynchronization device, a cardioverter-defibrillator. 14. An apparatus according to claim 12, further comprising: means for setting a logical flag to a high-alert condition responsive to the calculated one of: the dispersion of activation time, the recovery time, the activation recovery interval. 15. An apparatus according to claim 14, wherein the logical flag comprises one of an increased-tachyarrhythmia risk condition and a worsening heart function condition. 16. A computer readable medium for storing instructions providing control signals via a computer processor, comprising: instructions for detecting a plurality of localized electrogram (EGM) 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 disposed within a single chamber of the heart; instructions for measuring an activation time for a given cardiac cycle for each of the detected plurality of localized EGM signals; instructions for measuring a recovery time for the given cardiac cycle from each of the detected plurality of localized EGM 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 localized EGM signals; and instructions for calculating at least a one of: a dispersion of activation time, a recovery time, an activation recovery interval. 17. A computer readable medium according to claim 16, wherein in the event that a comparison of the value of an earlier calculated activation recovery interval with a subsequently calculated activation recovery interval reveals a temporally increasing activation recovery interval, then: instructions for declaring a worsening heart failure condition. 18. A computer readable medium according to claim 16, wherein in the event that a comparison of the value of an earlier calculated activation recovery interval with a subsequently calculated activation recovery interval reveals a temporally increasing activation recovery interval, then further comprising: instructions for declaring an increased risk for arrhythmias. 19. A computer readable medium according to claim 16, further comprising: instructions for delivering a cardiac pacing therapy in response to a relative increase in the activation recovery interval dispersion between a prior and a subsequent calculation of the activation recovery interval. 20. A computer readable medium according to claim 16, further comprising: instructions for adjusting a cardiac pacing therapy until a relative decrease occurs in the activation recovery interval between a prior and a subsequent calculation of the activation recovery interval. 21. A computer readable medium according to claim 16, further comprising: an implantable medical device (IMD); and electronic circuitry means coupled to the computer readable medium for operatively carrying out the instructions. 22. A computer readable medium according to claim 21, wherein the IMD comprises therapy delivery means for delivering a therapy responsive to the calculated one of: the dispersion of activation time, the recovery time, the activation recovery interval. 23. A computer readable medium according to claim 22, wherein the IMD comprises one of: a drug delivery device, a spinal cord stimulation device, a dual chamber pacemaker, a cardiac resynchronization device, a cardioverter-defibrillator.