Apparatus and method for spatially and temporally distributing cardiac electrical stimulation
View Patent ↗A cardiac electro-stimulatory device and method for operating same in which stimulation pulses are distributed among a plurality of electrodes fixed at different sites of the myocardium in order to reduce myocardial hypertrophy brought about by repeated pacing at a single site and/or increase myocardial contractility. In order to spatially and temporally distribute the stimulation, the pulses are delivered through a switchable pulse output configuration during a single cardiac cycle, with each configuration comprising one or more electrodes fixed to different sites in the myocardium.
1. A method for operating a cardiac pacing device, comprising:
outputting pacing pulses to a selected subset of a plurality of pacing electrodes in accordance with a programmed pacing mode, wherein the subset of electrodes to which pulses are output is defined by a pulse output configuration; and,
alternately switching between a first pulse output configuration utilized for one or more cardiac cycles and a second pulse output configuration for one or more subsequent cardiac cycles in accordance with a switching algorithm that comprises switching the pulse output configuration at specified time intervals.
2. The method of claim 1 further comprising sensing a parameter related to cardiac output and wherein the switching algorithm further comprises switching the pulse output configuration in a manner dependent upon the sensed parameter related to cardiac output.
3. The method of claim 1 further comprising outputting non-excitatory stimulation pulses to selected electrodes in conjunction with pacing pulses.
4. The method of claim 1 wherein a pulse output configuration is further defined as a temporal sequence of pulses output to a selected subset of electrodes during a cardiac cycle.
5. The method of claim 1 wherein the stimulation pulses are output to a bipolar electrode having tip and ring electrodes disposed near a heart chamber, and further comprising switching the pulse output configuration by alternating the polarity of the delivered pulses.
6. The method of claim 1 further comprising switching the pulse output configuration in accordance with the mean or minimum heart rate measured over a time interval.
7. The method of claim 1 further comprising switching the pulse output configuration in accordance with a sensed time delay of a depolarization occurring in an area of the myocardium after delivery of a pacing pulse.
8. A cardiac pacemaker, comprising:
a plurality of electrodes adapted for disposition near a heart chamber;
a plurality of defined pulse output configurations, wherein each pulse output configuration constitutes a subset of the plurality of the electrodes;
a control unit and pulse generating circuitry for outputting pacing pulses to a selected one of the plurality of pulse output configurations in accordance with a programmed mode;
wherein the control unit is programmed to alternately switch between a first pulse output configuration for one or more cardiac cycles and a second pulse output configuration for one or more cardiac cycles in accordance with a switching algorithm that comprises switching the pulse output configuration at specified time intervals.
9. The pacemaker of claim 8 further comprising a sensor for sensing a parameter related to cardiac output and wherein the switching algorithm further comprises switching the pulse output configuration in a manner dependent upon the sensed parameter related to cardiac output.
10. The pacemaker of claim 8 further comprising circuitry for outputting non-excitatory stimulation pulses to selected electrodes in conjunction with pacing pulses.
11. The pacemaker of claim 8 wherein a pulse output configuration is further defined as a temporal sequence of pulses output to a selected subset of electrodes during a cardiac cycle.
12. The pacemaker of claim 8 further comprising a bipolar electrode having tip and ring electrodes for disposition near a heart chamber, and wherein the pulse output configuration is switched by alternating the polarity of the delivered pulses.
13. The pacemaker of claim 8 wherein the switching algorithm further comprises switching the pulse output configuration in accordance with the mean or minimum heart rate measured over a time interval.
14. The pacemaker of claim 8 wherein the switching algorithm further comprises switching the pulse output configuration in accordance with a sensed time delay of a depolarization occurring in an area of the myocardium after delivery of a pacing pulse.
15. A method for operating a cardiac pacing device, comprising:
outputting pacing pulses to a selected subset of a plurality of pacing electrodes in accordance with a programmed pacing mode, wherein the subset of electrodes to which pulses are output is defined by a pulse output configuration; and,
switching the pulse output configuration utilized for one or more cardiac cycles to another pulse output configuration for one or more subsequent cardiac cycles in accordance with a switching algorithm that comprises switching the pulse output configuration after a specified number of heart beats.
16. The method of claim 15 further comprising sensing a parameter related to cardiac output and wherein the switching algorithm further comprises switching the pulse output configuration in a manner dependent upon the sensed parameter related to cardiac output.
17. A cardiac pacemaker, comprising:
a plurality of electrodes adapted for disposition near a heart chamber;
a plurality of defined pulse output configurations, wherein each pulse output configuration constitutes a subset of the plurality of the electrodes;
a control unit and pulse generating circuitry for outputting pacing pulses to a selected one of the plurality of pulse output configurations in accordance with a programmed mode;
wherein the control unit is programmed to utilize a first pulse output configuration during one or more cardiac cycles and switch to a second pulse output configuration during one or more subsequent cardiac cycles in accordance with a switching algorithm that comprises switching the pulse output configuration after a specified number of heart beats.
18. The pacemaker of claim 17 further comprising a sensor for sensing a parameter related to cardiac output and wherein the switching algorithm further comprises switching the pulse output configuration in a manner dependent upon the sensed parameter related to cardiac output.