Electrical muscle controller
A method of modifying the force of contraction of at least a portion of a heart chamber, including providing a subject having a heart, comprising at least a portion having an activation, and applying a non-excitatory electric field having a given duration, at a delay after the activation, to the portion, which causes the force of contraction to be increased by a least 5%.
1. Apparatus for non-excitatory modulation of activity of a heart, comprising:
an implantable housing;
a power supply within the housing;
at least one electrode coupled to said power supply and adapted to apply an electric field to a portion of a heart;
memory storing therein at least a first activation state indication of an activation state of a heart or portion thereof and an associated first timing parameter value and at least a second activation state indication of an activation state of a heart or a portion thereof and an associated second timing parameter value; and
circuitry which determines a delay using said timing parameter values in said memory and a present activation state of the heart and which controls said power supply to electrify said at least one electrode according to said delay to be within a refractory period of tissue at said portion.
2. Apparatus according to claim 1 , wherein said electric field has a timing, shape, frequency and amplitude suitable for increasing a contractility of tissue to which it is applied.
3. Apparatus according to claim 1 , wherein said delay is less than 70 msec from an expected activation time at said portion.
4. Apparatus according to claim 1 , wherein said delay is less than 150 msec from an expected activation time at said portion.
5. Apparatus according to claim 1 , wherein said circuitry determines said delay based on a time of pacing of the heart.
6. Apparatus according to claim 5 , wherein said pacing is in a different chamber of the heart than said portion.
7. Apparatus according to claim 1 , wherein said circuitry determines said delay based on a sensed activation time.
8. Apparatus according to claim 1 , wherein said circuitry determines said activation state by sensing.
9. Apparatus according to claim 1 , wherein said first activation state indication comprises an arrhythmia state indication.
10. Apparatus according to claim 1 , wherein said activation state indication distinguishes between the pacing source for the heart being natural or artificial.
11. Apparatus according to claim 1 , comprising at least one sensing circuit configured to detect a local activation.
12. Apparatus according to claim 11 , wherein said circuitry controls said power source in response to sensing of local activation at said at least one electrode.
13. Apparatus according to claim 11 , wherein said circuitry controls said power source in response to sensing of local activation at at least two temporally spaced apart electrodes.
14. Apparatus according to claim 13 , wherein said local activation is determined in a first chamber and in a second chamber in which said portion is.
15. Apparatus according to claim 1 , wherein said circuitry controls said power source in response to sensing of local activation at said at least one electrode in a same chamber as said portion.
16. Apparatus according to claim 11 , wherein said circuitry controls said power source in response to sensing of local activation, which local activation is caused by pacing of said heart.
17. A method of controlling a heart, comprising:
determining an activation profile of the heart, including if the heart is naturally or artificially paced; and
applying an electric field to a portion of said heart, during a refractory period of said portion, at a timing determined at least in part based on the identity of a pacing source of the heart.
18. A method according to claim 17 , comprising increasing a contractility of said heart by said applying.
19. A method according to claim 17 , comprising pacing said heart using a separate pacemaker and said determining is based on indication of pacing of the a present heart beat.
20. A method according to claim 17 , wherein said applying comprises using at least two of four electrodes which are positioned to apply said field to a same said portion.
21. A method according to claim 17 , wherein said timing is determined at a learning state of a controller used for said applying.